Xen devel - Mar 2013 - [PATCH] Provide support for multiple frame buffers in Xen

Support is provided for both shadow and hardware assisted paging (HAP)
modes. This code bookkeeps the set of video frame buffers (vram),
detects when the guest has modified any of those buffers and, upon request,
returns a bitmap of the modified pages.
This lets other software components re-paint the portions of the monitor
(or monitors) that have changed.
Each monitor has a frame buffer of some size at some position
in guest physical memory.
The set of frame buffers being tracked can change over time as monitors
are plugged and unplugged.

This is the 9th version of this patch.
Signed-Off-By: Robert Phillips <robert.phillips@citrix.com>
---
 tools/libxc/xenctrl.h            |   20 +-
 xen/arch/x86/hvm/hvm.c           |    8 +-
 xen/arch/x86/mm/Makefile         |    1 +
 xen/arch/x86/mm/dirty_vram.c     |  951 ++++++++++++++++++++++++++++++++++++++
 xen/arch/x86/mm/hap/hap.c        |  111 -----
 xen/arch/x86/mm/p2m.c            |   11 +-
 xen/arch/x86/mm/paging.c         |   57 ++-
 xen/arch/x86/mm/shadow/common.c  |  353 +++++++-------
 xen/arch/x86/mm/shadow/multi.c   |  174 ++++---
 xen/arch/x86/mm/shadow/multi.h   |    7 +-
 xen/arch/x86/mm/shadow/types.h   |    1 +
 xen/include/asm-x86/dirty_vram.h |  227 +++++++++
 xen/include/asm-x86/hap.h        |    4 -
 xen/include/asm-x86/hvm/domain.h |    2 +-
 xen/include/asm-x86/paging.h     |   15 +-
 xen/include/asm-x86/shadow.h     |    6 -
 16 files changed, 1535 insertions(+), 413 deletions(-)
 create mode 100644 xen/arch/x86/mm/dirty_vram.c
 create mode 100644 xen/include/asm-x86/dirty_vram.h

diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 32122fd..cd4e1ef 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -1563,15 +1563,23 @@ int xc_hvm_inject_msi(
     xc_interface *xch, domid_t dom, uint64_t addr, uint32_t data);
 
 /*
- * Track dirty bit changes in the VRAM area
+ * Track dirty bit changes in a VRAM region defined by
+ * [ first_pfn : first_pfn + nr - 1 ]
  *
  * All of this is done atomically:
- * - get the dirty bitmap since the last call
- * - set up dirty tracking area for period up to the next call
- * - clear the dirty tracking area.
+ * - gets the dirty bitmap since the last call, all zeroes for
+ *   the first call with some new region
+ * - sets up a dirty tracking region for period up to the next call
+ * - clears the specified dirty tracking region.
  *
- * Returns -ENODATA and does not fill bitmap if the area has changed since the
- * last call.
+ * Creating a new region causes any existing regions that it overlaps
+ * to be discarded.
+ *
+ * Specifying nr == 0 causes all regions to be discarded and
+ * disables dirty bit tracking.
+ *
+ * If nr is not a multiple of 64, only the first nr bits of bitmap
+ * are well defined.
  */
 int xc_hvm_track_dirty_vram(
     xc_interface *xch, domid_t dom,
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index fcea52c..5a97ad3 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -57,6 +57,7 @@
 #include <asm/hvm/cacheattr.h>
 #include <asm/hvm/trace.h>
 #include <asm/hvm/nestedhvm.h>
+#include <asm/dirty_vram.h>
 #include <asm/mtrr.h>
 #include <asm/apic.h>
 #include <public/sched.h>
@@ -1447,8 +1448,11 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
          */
         if ( access_w )
         {
-            paging_mark_dirty(v->domain, mfn_x(mfn));
-            p2m_change_type(v->domain, gfn, p2m_ram_logdirty, p2m_ram_rw);
+            if ( p2m_change_type(v->domain, gfn, p2m_ram_logdirty,
+                                 p2m_ram_rw) == p2m_ram_logdirty )
+            {
+                paging_mark_dirty_gpfn(v->domain, gfn);
+            }
         }
         rc = 1;
         goto out_put_gfn;
diff --git a/xen/arch/x86/mm/Makefile b/xen/arch/x86/mm/Makefile
index 73dcdf4..becd0c9 100644
--- a/xen/arch/x86/mm/Makefile
+++ b/xen/arch/x86/mm/Makefile
@@ -5,6 +5,7 @@ obj-y += paging.o
 obj-y += p2m.o p2m-pt.o p2m-ept.o p2m-pod.o
 obj-y += guest_walk_2.o
 obj-y += guest_walk_3.o
+obj-y += dirty_vram.o
 obj-$(x86_64) += guest_walk_4.o
 obj-$(x86_64) += mem_event.o
 obj-$(x86_64) += mem_paging.o
diff --git a/xen/arch/x86/mm/dirty_vram.c b/xen/arch/x86/mm/dirty_vram.c
new file mode 100644
index 0000000..4f599ed
--- /dev/null
+++ b/xen/arch/x86/mm/dirty_vram.c
@@ -0,0 +1,951 @@
+/*
+ * arch/x86/mm/dirty_vram.c: Bookkeep/query dirty VRAM pages
+ * with support for multiple frame buffers.
+ *
+ * Copyright (c) 2012, Citrix Systems, Inc. (Robert Phillips)
+ * Parts of this code are Copyright (c) 2007 Advanced Micro Devices (Wei Huang)
+ * Parts of this code are Copyright (c) 2007 XenSource Inc.
+ * Parts of this code are Copyright (c) 2006 by Michael A Fetterman
+ * Parts based on earlier work by Michael A Fetterman, Ian Pratt et al.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+
+#include <xen/types.h>
+#include <xen/sched.h>
+#include <xen/guest_access.h>
+#include <asm/shadow.h>
+#include <asm/dirty_vram.h>
+#include <asm/hap.h>
+#include <asm/config.h>
+#include "mm-locks.h"
+
+#define DEBUG_stop_tracking_all_vram          0
+#define DEBUG_allocating_dirty_vram_range     0
+#define DEBUG_high_water_mark_for_vram_ranges 0
+#define DEBUG_freeing_dirty_vram_range        0
+#define DEBUG_allocate_paddr_links_page       0
+#define DEBUG_update_vram_mapping             0
+#define DEBUG_alloc_paddr_inject_fault        0
+#define DEBUG_link_limit_exceeded             0
+
+
+/* Allocates domain''s dirty_vram structure */
+dv_dirty_vram_t *
+dirty_vram_alloc(struct domain *d)
+{
+    dv_dirty_vram_t *dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    dirty_vram = d->arch.hvm_domain.dirty_vram = xzalloc(dv_dirty_vram_t);
+    if ( dirty_vram )
+    {
+        INIT_LIST_HEAD(&dirty_vram->range_head);
+        dirty_vram->ext_head = INVALID_PADDR;
+        dirty_vram->pl_free = INVALID_PADDR;
+    }
+    return dirty_vram;
+}
+
+/*
+ * Returns domain''s dirty_vram structure,
+ * allocating it if necessary
+ */
+dv_dirty_vram_t *
+dirty_vram_find_or_alloc(struct domain *d)
+{
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    if ( !dirty_vram )
+        dirty_vram = dirty_vram_alloc(d);
+    return dirty_vram;
+}
+
+
+/* Free domain''s dirty_vram structure */
+void dirty_vram_free(struct domain *d)
+{
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    if ( dirty_vram )
+    {
+        struct list_head *curr, *next;
+        dv_paddr_link_ext_t *ext;
+        
+        /* Free all the ranges */
+        list_for_each_safe(curr, next, &dirty_vram->range_head)
+        {
+            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
+#if DEBUG_stop_tracking_all_vram
+            gdprintk(XENLOG_DEBUG, "[%05lx:%05lx] stop tracking all
vram\n",
+                     range->begin_pfn, range->end_pfn);
+#endif
+            xfree(range->pl_tab);
+            xfree(range);
+        }
+        /* Free all the extension pages */
+        
+        ext = remap_maddr(NULL, dirty_vram->ext_head);
+        while ( ext ) {
+            struct page_info *pg = virt_to_page(ext);
+            ext = remap_maddr(ext, ext->ext_link);
+            d->arch.paging.free_page(d, pg);
+        }
+
+        xfree(dirty_vram);
+        d->arch.hvm_domain.dirty_vram = NULL;
+    }
+}
+
+/* Returns dirty vram range containing gfn, NULL if none */
+struct dv_range *
+dirty_vram_range_find_gfn(struct domain *d,
+                          unsigned long gfn)
+{
+    struct dv_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    if ( dirty_vram )
+    {
+        struct list_head *curr;
+        list_for_each(curr, &dirty_vram->range_head)
+        {
+            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
+            if ( gfn >= range->begin_pfn &&
+                 gfn <  range->end_pfn )
+                return range;
+        }
+    }
+    return NULL;
+}
+
+/*
+ * Returns pointer to dirty vram range matching [begin_pfn .. end_pfn ),
+ * NULL if none.
+ */
+dv_range_t *
+dirty_vram_range_find(struct domain *d,
+                      unsigned long begin_pfn,
+                      unsigned long nr)
+{
+    unsigned long end_pfn = begin_pfn + nr;
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    if ( dirty_vram )
+    {
+        struct list_head *curr;
+        list_for_each(curr, &dirty_vram->range_head)
+        {
+            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
+            if ( begin_pfn == range->begin_pfn &&
+                 end_pfn   == range->end_pfn )
+                return range;
+        }
+    }
+    return NULL;
+}
+
+/* Allocate specified dirty_vram range */
+static dv_range_t *
+_dirty_vram_range_alloc(struct domain *d,
+                        unsigned long begin_pfn,
+                        unsigned long nr)
+{
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    dv_range_t *range = NULL;
+    unsigned long end_pfn = begin_pfn + nr;
+    dv_pl_entry_t *pl_tab = NULL;
+    int i;
+
+    ASSERT( paging_locked_by_me(d) );
+    ASSERT( dirty_vram != NULL );
+
+#if DEBUG_allocating_dirty_vram_range
+    gdprintk(XENLOG_DEBUG,
+             "[%05lx:%05lx] Allocating dirty vram range hap:%d\n",
+             begin_pfn, end_pfn,
+             d->arch.hvm_domain.hap_enabled);
+#endif
+
+    range = xzalloc(dv_range_t);
+    if ( range == NULL )
+        goto err_out;
+
+    INIT_LIST_HEAD(&range->range_link);
+
+    range->begin_pfn = begin_pfn;
+    range->end_pfn = end_pfn;
+
+    if ( !hap_enabled(d) )
+    {
+        if ( (pl_tab = xzalloc_array(dv_pl_entry_t, nr)) == NULL )
+            goto err_out;
+
+        for ( i = 0; i != nr; i++ )
+        {
+            pl_tab[i].mapping.sl1ma = INVALID_PADDR;
+            pl_tab[i].mapping.pl_next = INVALID_PADDR;
+        }
+    }
+
+    range->pl_tab = pl_tab;
+    range->mappings_hwm = 1;
+
+    list_add(&range->range_link, &dirty_vram->range_head);
+    if ( ++dirty_vram->nr_ranges > dirty_vram->ranges_hwm )
+    {
+        dirty_vram->ranges_hwm = dirty_vram->nr_ranges;
+#if DEBUG_high_water_mark_for_vram_ranges
+        gdprintk(XENLOG_DEBUG,
+                 "High water mark for number of vram ranges is
now:%d\n",
+                 dirty_vram->ranges_hwm);
+#endif
+    }
+    return range;
+
+ err_out:
+    xfree(pl_tab);
+    xfree(range);
+    return NULL;
+}
+
+/* Frees specified dirty_vram range */
+void dirty_vram_range_free(struct domain *d,
+                           dv_range_t *range)
+{
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    ASSERT( paging_locked_by_me(d) );
+    if ( dirty_vram )
+    {
+        int i, nr = range->end_pfn - range->begin_pfn;
+
+#if DEBUG_freeing_dirty_vram_range
+        gdprintk(XENLOG_DEBUG,
+                 "[%05lx:%05lx] Freeing dirty vram range\n",
+                 range->begin_pfn, range->end_pfn);
+#endif
+
+        if ( range->pl_tab )
+        {
+            for ( i = 0; i != nr; i++ )
+            {
+                dv_paddr_link_t *plx;
+                
+                plx = remap_maddr(NULL, range->pl_tab[i].mapping.pl_next);
+
+                /* Does current FB page have multiple mappings? */
+                if ( plx ) /* Yes */
+                {
+                    /* Find the last element in singly-linked list */
+                    while ( plx->pl_next != INVALID_PADDR ) {
+                        plx = remap_maddr(plx, plx->pl_next);
+                    }
+                    
+                    /* Prepend whole list to the free list */
+                    plx->pl_next = dirty_vram->pl_free;
+                    dirty_vram->pl_free =
range->pl_tab[i].mapping.pl_next;
+                }
+                /* Unmap plx. */
+                remap_vaddr(plx, NULL);
+            }
+            xfree(range->pl_tab);
+            range->pl_tab = NULL;
+        }
+        /* Remove range from the linked list, free it, and adjust count*/
+        list_del(&range->range_link);
+        xfree(range);
+        dirty_vram->nr_ranges--;
+    }
+}
+
+/*
+ * dirty_vram_range_alloc()
+ * This function ensures that the new range does not overlap any existing
+ * ranges -- deleting them if necessary -- and then calls
+ * _dirty_vram_range_alloc to actually allocate the new range.
+ */
+dv_range_t *
+dirty_vram_range_alloc(struct domain *d,
+                        unsigned long begin_pfn,
+                        unsigned long nr)
+{
+    unsigned long end_pfn = begin_pfn + nr;
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    dv_range_t *range;
+    struct list_head *curr, *next;
+
+    ASSERT( paging_locked_by_me(d) );
+    ASSERT( dirty_vram != NULL );
+
+    /*
+     * Ranges cannot overlap so
+     * free any range that overlaps [ begin_pfn .. end_pfn ).
+     */
+    list_for_each_safe(curr, next, &dirty_vram->range_head)
+    {
+        dv_range_t *rng = list_entry(curr, dv_range_t, range_link);
+        if ( ( ( rng->begin_pfn <= begin_pfn ) &&
+               ( begin_pfn <  rng->end_pfn   )
+                 ) ||
+             ( ( begin_pfn <= rng->begin_pfn ) &&
+               ( rng->begin_pfn < end_pfn    )
+                 ) )
+        {
+            /* Different tracking, tear the previous down. */
+            dirty_vram_range_free(d, rng);
+        }
+    }
+
+    range = _dirty_vram_range_alloc(d, begin_pfn, nr);
+    if ( !range )
+        goto out;
+
+ out:
+    return range;
+}
+
+/*
+ * dirty_vram_range_find_or_alloc()
+ * Find the range for [begin_pfn:begin_pfn+nr).
+ * If it doesn''t exists, create it.
+ */
+dv_range_t *
+dirty_vram_range_find_or_alloc(struct domain *d,
+                                unsigned long begin_pfn,
+                                unsigned long nr)
+{
+    dv_range_t *range;
+    ASSERT( paging_locked_by_me(d) );
+    range = dirty_vram_range_find(d, begin_pfn, nr);
+    if ( !range )
+        range = dirty_vram_range_alloc(d, begin_pfn, nr);
+    
+    return range;
+}
+
+
+static paddr_t
+domain_page_map_to_maddr(void *va)
+{
+    if ( va )
+        return (domain_page_map_to_mfn(va) << PAGE_SHIFT) +
+            (((unsigned long)va) & ~PAGE_MASK);
+    else
+        return INVALID_PADDR;
+}
+
+void *
+remap_maddr(void *old_va, paddr_t new_ma)
+{
+    if ( old_va )
+        unmap_domain_page(old_va);
+    
+    if ( new_ma != INVALID_PADDR )
+        return map_domain_page(new_ma >> PAGE_SHIFT) + (new_ma &
~PAGE_MASK);
+    else
+        return NULL;
+}
+
+void *
+remap_vaddr(void *old_va, void *new_va)
+{
+    if ( old_va )
+        unmap_domain_page(old_va);
+    
+    if ( new_va )
+        /* Map page now in anticipation of future matching unmap */
+        map_domain_page(domain_page_map_to_mfn(new_va));
+
+    return new_va;
+}
+
+
+/* Allocate a dv_paddr_link struct */
+static dv_paddr_link_t *
+alloc_paddr_link(struct domain *d)
+{
+    dv_paddr_link_t *pl = NULL;
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    dv_paddr_link_ext_t *ext = NULL;
+    
+
+    ASSERT( paging_locked_by_me(d) );
+    BUILD_BUG_ON(sizeof(dv_paddr_link_ext_t) > PAGE_SIZE);
+    /* Is the list of free pl''s empty? */
+    if ( dirty_vram->pl_free == INVALID_PADDR ) /* Yes. */
+    {
+        /*
+         * Allocate another page of pl''s.
+         * Link them all together and point the free list head at them
+         */
+        int i;
+        struct page_info *pg = d->arch.paging.alloc_page(d);
+        if ( pg == NULL )
+            goto out;
+
+        ext = __map_domain_page(pg);
+        if ( ext == NULL )
+        {
+            d->arch.paging.free_page(d, pg);
+            goto out;
+        }
+
+#if DEBUG_allocate_paddr_links_page
+        gdprintk(XENLOG_DEBUG, "Allocated another page of
paddr_links\n");
+#endif
+        /* Prepend new extension page to dirty_vram''s list of same. */
+        ext->ext_link = dirty_vram->ext_head;
+        dirty_vram->ext_head = domain_page_map_to_maddr(ext);
+
+        /* Initialize and link together the new pl entries. */
+        for ( i = 0; i != ARRAY_SIZE(ext->entries); i++ )
+        {
+            ext->entries[i].sl1ma = INVALID_PADDR;
+            ext->entries[i].pl_next +               
domain_page_map_to_maddr(&ext->entries[i+1]);
+        }
+        /* Mark the last entry''s next pointer as "null". */
+        ext->entries[ARRAY_SIZE(ext->entries) - 1].pl_next =
INVALID_PADDR;
+
+        /* Set the dirty_vram''s free list pointer to the first entry.
*/
+        dirty_vram->pl_free =
domain_page_map_to_maddr(&ext->entries[0]);
+    }
+    pl = remap_maddr(NULL, dirty_vram->pl_free);
+    dirty_vram->pl_free = pl->pl_next;
+
+    pl->sl1ma = INVALID_PADDR;
+    pl->pl_next = INVALID_PADDR;
+ out:
+    if ( ext )
+        unmap_domain_page(ext);
+    return pl;
+}
+
+
+/*
+ * Free a paddr_link struct.
+ *
+ * The caller has walked the singly-linked list of elements
+ * that have, as their head, an element in a pl_tab cell.
+ * The list walk has reached the element to be freed.
+ * (Each element is a dv_paddr_link_t struct.)
+ *
+ * @pl points to the element to be freed.
+ * @ppl points to its predecessor''s next member.
+ *
+ * After linking the predecessor to the element''s successor,
+ * we can free @pl by prepending it to the list of free
+ * elements.
+ *
+ * As a boundary case (which happens to be the common case),
+ * @pl points to a cell in the pl_tab rather than to some
+ * extension element danging from that cell.
+ * We recognize this case because @ppl is NULL.
+ * In that case we promote the first extension element by
+ * copying it into the pl_tab cell and freeing it.
+ *
+ * Returns a pointer to @pl''s successor.  This is where
+ * any iterative processing will resume.
+ */
+
+dv_paddr_link_t *
+free_paddr_link(struct domain *d,
+                paddr_t *ppl,
+                dv_paddr_link_t *pl)
+{
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    dv_paddr_link_t *npl; /* Next pl. */
+
+    ASSERT( paging_locked_by_me(d) );
+    /* Extension mapping? */
+    if ( ppl ) /* Yes, relink around it. */
+    {
+        /* When done, resume processing at pl''s successor. */
+        npl = remap_maddr(NULL, pl->pl_next);
+        (*ppl) = domain_page_map_to_maddr(npl);
+    }
+    else  /* pl points to entry in the main table. */
+    {
+        /*
+         * Move 2nd mapping to main table
+         * and free 2nd mapping.
+         */
+        dv_paddr_link_t *spl; /* 2nd mapping */
+        spl = remap_maddr(NULL, pl->pl_next);
+        /* Is there a 2nd mapping? */
+        if ( spl == NULL ) /* No. */
+        {
+            /* Invalidate the main table entry. */
+            pl->sl1ma = INVALID_PADDR;
+            return pl;
+        }
+        /* Copy 2nd mapping into main table. */
+        pl->sl1ma = spl->sl1ma;
+        pl->pl_next = spl->pl_next;
+        npl = pl; /* Reprocess main table entry again. */
+        pl = spl; /* Prepare to free 2nd mapping. */
+    }
+
+    /* Prepare entry for prepending to the free list */
+    pl->sl1ma = INVALID_PADDR;
+    pl->pl_next = dirty_vram->pl_free;
+    dirty_vram->pl_free = domain_page_map_to_maddr(pl);
+    remap_vaddr(pl, NULL); /* Unmap pl. */
+
+    return npl;
+}
+
+
+/*
+ * dirty_vram_range_update()
+ *
+ * This is called whenever a level 1 page table entry is modified.
+ * If the L1PTE is being cleared, the function removes any paddr_links
+ * that refer to it.
+ * If the L1PTE is being set to a frame buffer page, a paddr_link is
+ * created for that page''s entry in pl_tab.
+ * Returns 1 iff entry found and set or cleared.
+ */
+int dirty_vram_range_update(struct domain *d,
+                            unsigned long gfn,
+                            paddr_t sl1ma,
+                            int set)
+{
+    int effective = 0;
+    dv_range_t *range;
+    unsigned long i;
+    dv_paddr_link_t *pl;
+    paddr_t *ppl;
+    int len = 0;
+
+    ASSERT(paging_locked_by_me(d));
+    range = dirty_vram_range_find_gfn(d, gfn);
+    if ( !range )
+        return effective;
+
+    
+    i = gfn - range->begin_pfn;
+    pl = remap_vaddr(NULL, &range->pl_tab[ i ].mapping);
+    ppl = NULL;
+    /*
+     * Find matching entry (pl), if any, and its predecessor (ppl)
+     * in linked list.
+     */
+    while ( pl != NULL )
+    {
+        if ( pl->sl1ma == sl1ma || pl->sl1ma == INVALID_PADDR )
+            break;
+
+        ppl = remap_vaddr(ppl, &pl->pl_next);
+        pl =  remap_maddr(pl, (*ppl));
+        len++;
+    }
+    
+    if ( set )
+    {
+        /* Did we find sl1ma in either the main table or the linked list? */
+        if ( pl == NULL ) /* No, so we''ll need to alloc a link. */
+        {
+            ASSERT(ppl != NULL); /* ppl points to predecessor''s next
link. */
+            
+#if DEBUG_alloc_paddr_inject_fault
+            {
+                static int counter;
+                
+                /* Test stuck_dirty logic for some cases */
+                if ( (++counter) % 4 == 0 )
+                {
+                    /* Simply mark the frame buffer page as always dirty */
+                    range->pl_tab[ i ].stuck_dirty = 1;
+                    gdprintk(XENLOG_DEBUG,
+                             "[%lx] inject stuck dirty fault\n",
+                             gfn );
+                    goto out;
+                }
+            }
+#endif
+            /*
+             * Have we reached the limit of mappings we''re willing
+             * to bookkeep?
+             */
+            if ( len > DV_ADDR_LINK_LIST_LIMIT ) /* Yes. */
+            {
+#if DEBUG_link_limit_exceeded
+                if ( !range->pl_tab[ i ].stuck_dirty )
+                    gdprintk(XENLOG_DEBUG,
+                             "[%lx] link limit exceeded\n",
+                             gfn );
+#endif            
+                /* Simply mark the frame buffer page as always dirty */
+                range->pl_tab[ i ].stuck_dirty = 1;
+                goto out;
+            }
+
+            /* Alloc new link */
+            pl = alloc_paddr_link(d);
+            /* Were we able to allocate a link? */
+            if ( pl == NULL ) /* No. */
+            {
+                /* Simply mark the frame buffer page as always dirty */
+                range->pl_tab[ i ].stuck_dirty = 1;
+                
+                gdprintk(XENLOG_DEBUG,
+                         "[%lx] alloc failure\n",
+                         gfn );
+                
+                goto out;
+            }
+            /* Append new link to the list */
+            (*ppl) = domain_page_map_to_maddr(pl);
+        }
+
+        /* Did we find an entry for sl1ma? */
+        if ( pl->sl1ma != sl1ma ) /* No. */
+        {
+            /* pl must point to either a previously unused entry in the
+             * main table, or to a newly allocated link.
+             * In either case, the link''s sl1ma should be
''null''.
+             */
+            ASSERT(pl->sl1ma == INVALID_PADDR);
+            pl->sl1ma = sl1ma;
+        }
+        effective = 1; /* Take note that we''re going to set an entry.
*/
+        if ( len > range->mappings_hwm )
+        {
+            /* Bookkeep the high water mark. */
+            range->mappings_hwm = len;
+#if DEBUG_update_vram_mapping
+            gdprintk(XENLOG_DEBUG,
+                     "[%lx] set      sl1ma:%lx hwm:%d "
+                     "free_pages:%d\n",
+                     gfn, sl1ma,
+                     range->mappings_hwm,
+                     d->arch.paging.shadow.free_pages);
+#endif
+        }
+    }
+    else /* Clear */
+    {
+        if ( pl && pl->sl1ma == sl1ma )
+        {
+#if DEBUG_update_vram_mapping
+            gdprintk(XENLOG_DEBUG,
+                     "[%lx] clear    sl1ma:%lx\n",
+                     gfn, sl1ma);
+#endif
+            pl = free_paddr_link(d, ppl, pl);
+            effective = 1; /* Take note that we''re clearing an entry.
*/
+        }
+    }
+ out:
+    remap_vaddr(pl,  NULL);
+    remap_vaddr(ppl, NULL);
+    return effective;
+}
+
+
+/*
+ * shadow_scan_dirty_flags()
+ * This produces a dirty bitmap for the range by examining every
+ * L1PTE referenced by some dv_paddr_link in the range''s pl_tab table.
+ * It tests and clears each such L1PTE''s dirty flag.
+ */
+static int 
+shadow_scan_dirty_flags(struct domain *d,
+                        dv_range_t *range,
+                        uint8_t *dirty_bitmap)
+{
+    int flush_tlb = 0;
+    unsigned long i;
+    unsigned long nr = range->end_pfn - range->begin_pfn;
+    l1_pgentry_t *sl1e = NULL;
+
+    ASSERT( paging_locked_by_me(d) );
+    /* Iterate over VRAM to track dirty bits. */
+    for ( i = 0; i < nr; i++ )
+    {
+        int dirty = 0;
+        
+        /* Does the frame buffer have an incomplete set of mappings? */
+        if ( unlikely(range->pl_tab[i].stuck_dirty) ) /* Yes. */
+            dirty = 1; /* Then always assume the page is dirty. */
+        else { /* The frame buffer''s set of mappings is complete. 
Scan it. */
+            paddr_t next = range->pl_tab[i].mapping.pl_next;
+            paddr_t sl1ma = range->pl_tab[i].mapping.sl1ma;
+            dv_paddr_link_t *pl = NULL;
+            for (;;)
+            {
+                if ( sl1ma == INVALID_PADDR )
+                    /* End of list or frame buffer page is unmapped. */
+                    break;
+
+                if ( sl1e ) /* Cleanup from previous iteration. */
+                    unmap_domain_page(sl1e);
+
+                sl1e = map_domain_page(sl1ma >> PAGE_SHIFT) +
+                    (sl1ma & ~PAGE_MASK);
+                if ( l1e_get_flags(*sl1e) & _PAGE_DIRTY )
+                {
+                    dirty = 1;
+                    /* Clear dirty so we can detect if page gets re-dirtied.
+                     * Note: this is atomic, so we may clear a
+                     * _PAGE_ACCESSED set by another processor.
+                     */
+                    l1e_remove_flags(*sl1e, _PAGE_DIRTY);
+                    flush_tlb = 1;
+                    /* Even though we now know the frame buffer page is dirty,
+                     * keep iterating to clear the dirty flag in all other
+                     * mappings. 
+                     */
+                }
+                
+                pl = remap_maddr(pl, next);
+                if ( !pl )
+                    break;
+                
+                next = pl->pl_next;
+                sl1ma = pl->sl1ma;
+            } /* for */
+
+            /* Unmap pl. */
+            remap_vaddr(NULL, pl);
+        }
+        if ( dirty )
+            /* Set the i''th bit in the output dirty_bitmap */
+            dirty_bitmap[i >> 3] |= (1 << (i & 7));
+
+    }
+    
+    if ( sl1e )
+        unmap_domain_page(sl1e);
+
+    return flush_tlb;
+}
+
+
+/*
+ * shadow_track_dirty_vram()
+ * This is the API called by the guest to determine which pages in the range
+ * from [begin_pfn:begin_pfn+nr) have been dirtied since the last call.
+ * It creates the domain''s dv_dirty_vram on demand.
+ * It creates ranges on demand when some [begin_pfn:nr) is first encountered.
+ * To collect the dirty bitmask it calls shadow_scan_dirty_flags().
+ * It copies the dirty bitmask into guest storage.
+ */
+int shadow_track_dirty_vram(struct domain *d,
+                            unsigned long begin_pfn,
+                            unsigned long nr,
+                            XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
+{
+    int rc = 0;
+    unsigned long end_pfn = begin_pfn + nr;
+    int flush_tlb = 0;
+    dv_range_t *range;
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+    uint8_t *dirty_bitmap = NULL;
+
+    /*
+     * This range test is tricky.
+     *
+     * The range [begin_pfn..end_pfn) is an open interval, so end_pfn
+     * is a pfn beyond the end of the range.
+     *
+     * p2m->max_mapped_pfn is a valid PFN so p2m->max_mapped_pfn + 1 is
an
+     * invalid PFN.
+     *
+     * If end_pfn is beyond *that* then the range is invalid.
+     */
+    if ( end_pfn < begin_pfn
+         || begin_pfn > p2m->max_mapped_pfn
+         || end_pfn > p2m->max_mapped_pfn + 1 )
+        return -EINVAL;
+
+    paging_lock(d);
+
+    if ( !nr )
+    {
+        dirty_vram_free(d);
+        goto out;
+    }
+
+    if ( guest_handle_is_null(guest_dirty_bitmap) )
+        goto out;
+
+    if ( !dirty_vram_find_or_alloc(d) )
+    {
+        rc = -ENOMEM;
+        goto out;
+    }
+
+    range = dirty_vram_range_find(d, begin_pfn, nr);
+    if ( !range )
+    {
+        range = dirty_vram_range_alloc(d, begin_pfn, nr);
+        if ( range )
+            sh_find_all_vram_mappings(d->vcpu[0], range);
+    }
+    if ( range )
+    {
+        int size = ( nr + BITS_PER_BYTE - 1 ) / BITS_PER_BYTE;
+        
+        rc = -ENOMEM;
+        dirty_bitmap = xzalloc_bytes( size );
+        if ( !dirty_bitmap )
+            goto out;
+
+        flush_tlb |= shadow_scan_dirty_flags(d, range, dirty_bitmap);
+
+        rc = -EFAULT;
+        if ( copy_to_guest(guest_dirty_bitmap,
+                           dirty_bitmap,
+                           size) == 0 )
+            rc = 0;
+    }
+    
+    if ( flush_tlb )
+        flush_tlb_mask(d->domain_dirty_cpumask);
+
+out:
+    paging_unlock(d);
+    
+    if ( dirty_bitmap )
+        xfree(dirty_bitmap);
+    return rc;
+}
+
+
+/************************************************/
+/*          HAP VRAM TRACKING SUPPORT           */
+/************************************************/
+
+/*
+ * hap_track_dirty_vram()
+ * Create the domain''s dv_dirty_vram struct on demand.
+ * Create a dirty vram range on demand when some [begin_pfn:begin_pfn+nr] is
+ * first encountered.
+ * Collect the guest_dirty bitmask, a bit mask of the dirty vram pages, by
+ * calling paging_log_dirty_range(), which interrogates each vram
+ * page''s p2m type looking for pages that have been made writable.
+ */
+int hap_track_dirty_vram(struct domain *d,
+                         unsigned long begin_pfn,
+                         unsigned long nr,
+                         XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
+{
+    long rc = 0;
+    dv_dirty_vram_t *dirty_vram;
+    uint8_t *dirty_bitmap = NULL;
+
+    if ( nr )
+    {
+        dv_range_t *range = NULL;
+        int size = ( nr + BITS_PER_BYTE - 1 ) / BITS_PER_BYTE;
+        
+        if ( !paging_mode_log_dirty(d) )
+        {
+            hap_logdirty_init(d);
+            rc = paging_log_dirty_enable(d);
+            if ( rc )
+                goto out;
+        }
+
+        rc = -ENOMEM;
+        dirty_bitmap = xzalloc_bytes( size );
+        if ( !dirty_bitmap )
+            goto out;
+        
+        paging_lock(d);
+        
+        dirty_vram = d->arch.hvm_domain.dirty_vram;
+        if ( !dirty_vram ) 
+        {
+            rc = -ENOMEM;
+            if ( !(dirty_vram = dirty_vram_alloc(d)) )
+            {
+                paging_unlock(d);
+                goto out;
+            }
+        }
+        
+        range = dirty_vram_range_find(d, begin_pfn, nr);
+        if ( !range )
+        {
+            rc = -ENOMEM;
+            if ( !(range = dirty_vram_range_alloc(d, begin_pfn, nr)) )
+            {
+                paging_unlock(d);
+                goto out;
+            }
+            
+            paging_unlock(d);
+            
+            /* Set l1e entries of range within P2M table to be read-only. */
+            p2m_change_type_range(d, begin_pfn, begin_pfn + nr,
+                                  p2m_ram_rw, p2m_ram_logdirty);
+            
+            flush_tlb_mask(d->domain_dirty_cpumask);
+            
+            memset(dirty_bitmap, 0xff, size); /* Consider all pages dirty. */
+        }
+        else
+        {
+            paging_unlock(d);
+            
+            domain_pause(d);
+            
+            /* Get the bitmap. */
+            paging_log_dirty_range(d, begin_pfn, nr, dirty_bitmap);
+            
+            domain_unpause(d);
+        }
+        
+        
+        rc = -EFAULT;
+        if ( copy_to_guest(guest_dirty_bitmap,
+                           dirty_bitmap,
+                           size) == 0 )
+        {
+            rc = 0;
+        }
+    }
+    else {
+        paging_lock(d);
+        
+        dirty_vram = d->arch.hvm_domain.dirty_vram;
+        if ( dirty_vram )
+        {
+            /*
+             * If zero pages specified while tracking dirty vram
+             * then stop tracking
+             */
+            dirty_vram_free(d);
+        
+        }
+        
+        paging_unlock(d);
+    }
+out:
+    if ( dirty_bitmap )
+        xfree(dirty_bitmap);
+    
+    return rc;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index f353d3a..3ac54c9 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -53,117 +53,6 @@
 #define page_to_mfn(_pg) _mfn(__page_to_mfn(_pg))
 
 /************************************************/
-/*          HAP VRAM TRACKING SUPPORT           */
-/************************************************/
-
-/*
- * hap_track_dirty_vram()
- * Create the domain''s dv_dirty_vram struct on demand.
- * Create a dirty vram range on demand when some [begin_pfn:begin_pfn+nr] is
- * first encountered.
- * Collect the guest_dirty bitmask, a bit mask of the dirty vram pages, by
- * calling paging_log_dirty_range(), which interrogates each vram
- * page''s p2m type looking for pages that have been made writable.
- */
-
-int hap_track_dirty_vram(struct domain *d,
-                         unsigned long begin_pfn,
-                         unsigned long nr,
-                         XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
-{
-    long rc = 0;
-    struct sh_dirty_vram *dirty_vram;
-    uint8_t *dirty_bitmap = NULL;
-
-    if ( nr )
-    {
-        int size = (nr + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
-
-        if ( !paging_mode_log_dirty(d) )
-        {
-            hap_logdirty_init(d);
-            rc = paging_log_dirty_enable(d);
-            if ( rc )
-                goto out;
-        }
-
-        rc = -ENOMEM;
-        dirty_bitmap = xzalloc_bytes(size);
-        if ( !dirty_bitmap )
-            goto out;
-
-        paging_lock(d);
-
-        dirty_vram = d->arch.hvm_domain.dirty_vram;
-        if ( !dirty_vram )
-        {
-            rc = -ENOMEM;
-            if ( (dirty_vram = xzalloc(struct sh_dirty_vram)) == NULL )
-            {
-                paging_unlock(d);
-                goto out;
-            }
-
-            d->arch.hvm_domain.dirty_vram = dirty_vram;
-        }
-
-        if ( begin_pfn != dirty_vram->begin_pfn ||
-             begin_pfn + nr != dirty_vram->end_pfn )
-        {
-            dirty_vram->begin_pfn = begin_pfn;
-            dirty_vram->end_pfn = begin_pfn + nr;
-
-            paging_unlock(d);
-
-            /* set l1e entries of range within P2M table to be read-only. */
-            p2m_change_type_range(d, begin_pfn, begin_pfn + nr,
-                                  p2m_ram_rw, p2m_ram_logdirty);
-
-            flush_tlb_mask(d->domain_dirty_cpumask);
-
-            memset(dirty_bitmap, 0xff, size); /* consider all pages dirty */
-        }
-        else
-        {
-            paging_unlock(d);
-
-            domain_pause(d);
-
-            /* get the bitmap */
-            paging_log_dirty_range(d, begin_pfn, nr, dirty_bitmap);
-
-            domain_unpause(d);
-        }
-
-        rc = -EFAULT;
-        if ( copy_to_guest(guest_dirty_bitmap, dirty_bitmap, size) == 0 )
-            rc = 0;
-    }
-    else
-    {
-        paging_lock(d);
-
-        dirty_vram = d->arch.hvm_domain.dirty_vram;
-        if ( dirty_vram )
-        {
-            /*
-             * If zero pages specified while tracking dirty vram
-             * then stop tracking
-             */
-            xfree(dirty_vram);
-            d->arch.hvm_domain.dirty_vram = NULL;
-        }
-
-        paging_unlock(d);
-    }
-out:
-    if ( dirty_bitmap )
-        xfree(dirty_bitmap);
-
-    return rc;
-}
-
-/************************************************/
 /*            HAP LOG DIRTY SUPPORT             */
 /************************************************/
 
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index de1dd82..6f638a2 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -741,20 +741,23 @@ void p2m_change_type_range(struct domain *d,
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
 
     BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
-
     p2m_lock(p2m);
-    p2m->defer_nested_flush = 1;
 
+    p2m->defer_nested_flush = 1;
+    
     for ( gfn = start; gfn < end; gfn++ )
     {
         mfn = p2m->get_entry(p2m, gfn, &pt, &a, 0, NULL);
         if ( pt == ot )
-            set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, nt,
p2m->default_access);
+            set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, nt,
+                          p2m->default_access);
     }
-
+    
     p2m->defer_nested_flush = 0;
+
     if ( nestedhvm_enabled(d) )
         p2m_flush_nestedp2m(d);
+
     p2m_unlock(p2m);
 }
 
diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index ac9bb1a..d59e8d6 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -27,6 +27,7 @@
 #include <asm/p2m.h>
 #include <asm/hap.h>
 #include <asm/hvm/nestedhvm.h>
+#include <asm/dirty_vram.h>
 #include <xen/numa.h>
 #include <xsm/xsm.h>
 
@@ -192,15 +193,11 @@ int paging_log_dirty_disable(struct domain *d)
     return ret;
 }
 
-/* Mark a page as dirty */
+/* Given a guest mfn, mark a page as dirty */
 void paging_mark_dirty(struct domain *d, unsigned long guest_mfn)
 {
     unsigned long pfn;
     mfn_t gmfn;
-    int changed;
-    mfn_t mfn, *l4, *l3, *l2;
-    unsigned long *l1;
-    int i1, i2, i3, i4;
 
     gmfn = _mfn(guest_mfn);
 
@@ -210,6 +207,19 @@ void paging_mark_dirty(struct domain *d, unsigned long
guest_mfn)
 
     /* We /really/ mean PFN here, even for non-translated guests. */
     pfn = get_gpfn_from_mfn(mfn_x(gmfn));
+    paging_mark_dirty_gpfn(d, pfn);
+}
+
+
+/* Given a guest pfn, mark a page as dirty */
+void paging_mark_dirty_gpfn(struct domain *d, unsigned long pfn)
+{
+    int changed;
+    mfn_t mfn, *l4, *l3, *l2;
+    unsigned long *l1;
+    int i1, i2, i3, i4;
+    dv_range_t *range;
+    
     /* Shared MFNs should NEVER be marked dirty */
     BUG_ON(SHARED_M2P(pfn));
 
@@ -229,6 +239,11 @@ void paging_mark_dirty(struct domain *d, unsigned long
guest_mfn)
     /* Recursive: this is called from inside the shadow code */
     paging_lock_recursive(d);
 
+    d->arch.paging.log_dirty.dirty_count++;
+    range = dirty_vram_range_find_gfn(d, pfn);
+    if ( range )
+        range->dirty_count++;
+
     if ( unlikely(!mfn_valid(d->arch.paging.log_dirty.top)) ) 
     {
          d->arch.paging.log_dirty.top = paging_new_log_dirty_node(d);
@@ -445,7 +460,31 @@ void paging_log_dirty_range(struct domain *d,
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
     int i;
     unsigned long pfn;
+    dv_range_t *range;
+    unsigned int range_dirty_count;
 
+    paging_lock(d);
+    range = dirty_vram_range_find_gfn(d, begin_pfn);
+    if ( !range )
+    {
+        paging_unlock(d);
+        goto out;
+    }
+    
+    range_dirty_count = range->dirty_count;
+    range->dirty_count = 0;
+
+    paging_unlock(d);
+    
+    if ( !range_dirty_count)
+        goto out;
+
+    PAGING_DEBUG(LOGDIRTY,
+                 "log-dirty-range: dom %u [%05lx:%05lx]
range_dirty=%u\n",
+                 d->domain_id,
+                 begin_pfn,
+                 begin_pfn + nr,
+                 range_dirty_count);
     /*
      * Set l1e entries of P2M table to be read-only.
      *
@@ -460,15 +499,17 @@ void paging_log_dirty_range(struct domain *d,
 
     for ( i = 0, pfn = begin_pfn; pfn < begin_pfn + nr; i++, pfn++ )
     {
-        p2m_type_t pt;
-        pt = p2m_change_type(d, pfn, p2m_ram_rw, p2m_ram_logdirty);
-        if ( pt == p2m_ram_rw )
+        if ( p2m_change_type(d, pfn, p2m_ram_rw, p2m_ram_logdirty) =+          
p2m_ram_rw )
             dirty_bitmap[i >> 3] |= (1 << (i & 7));
     }
 
     p2m_unlock(p2m);
 
     flush_tlb_mask(d->domain_dirty_cpumask);
+
+ out:
+    return;
 }
 
 /* Note that this function takes three function pointers. Callers must supply
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 292c1f7..b72a6bb 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -36,6 +36,7 @@
 #include <asm/current.h>
 #include <asm/flushtlb.h>
 #include <asm/shadow.h>
+#include <asm/dirty_vram.h>
 #include <xen/numa.h>
 #include "private.h"
 
@@ -3121,12 +3122,7 @@ void shadow_teardown(struct domain *d)
      * calls now that we''ve torn down the bitmap */
     d->arch.paging.mode &= ~PG_log_dirty;
 
-    if (d->arch.hvm_domain.dirty_vram) {
-        xfree(d->arch.hvm_domain.dirty_vram->sl1ma);
-        xfree(d->arch.hvm_domain.dirty_vram->dirty_bitmap);
-        xfree(d->arch.hvm_domain.dirty_vram);
-        d->arch.hvm_domain.dirty_vram = NULL;
-    }
+    dirty_vram_free(d);
 
     paging_unlock(d);
 
@@ -3464,194 +3460,219 @@ void shadow_clean_dirty_bitmap(struct domain *d)
 
 /**************************************************************************/
 /* VRAM dirty tracking support */
-int shadow_track_dirty_vram(struct domain *d,
-                            unsigned long begin_pfn,
-                            unsigned long nr,
-                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap)
-{
-    int rc;
-    unsigned long end_pfn = begin_pfn + nr;
-    unsigned long dirty_size = (nr + 7) / 8;
-    int flush_tlb = 0;
-    unsigned long i;
-    p2m_type_t t;
-    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
-    struct p2m_domain *p2m = p2m_get_hostp2m(d);
 
-    if (end_pfn < begin_pfn
-            || begin_pfn > p2m->max_mapped_pfn
-            || end_pfn >= p2m->max_mapped_pfn)
-        return -EINVAL;
 
-    /* We perform p2m lookups, so lock the p2m upfront to avoid deadlock */
-    p2m_lock(p2m_get_hostp2m(d));
-    paging_lock(d);
+/* Support functions for shadow-based dirty VRAM code */
 
-    if ( dirty_vram && (!nr ||
-             ( begin_pfn != dirty_vram->begin_pfn
-            || end_pfn   != dirty_vram->end_pfn )) )
-    {
-        /* Different tracking, tear the previous down. */
-        gdprintk(XENLOG_INFO, "stopping tracking VRAM %lx - %lx\n",
dirty_vram->begin_pfn, dirty_vram->end_pfn);
-        xfree(dirty_vram->sl1ma);
-        xfree(dirty_vram->dirty_bitmap);
-        xfree(dirty_vram);
-        dirty_vram = d->arch.hvm_domain.dirty_vram = NULL;
-    }
+#define DEBUG_unshadow_sl1ma                  0          
+#define DEBUG_unshadow_sl1ma_detail           0
+#define DEBUG_count_initial_mappings          0
 
-    if ( !nr )
+/* smfn is no longer a shadow page.  Remove it from any
+ * dirty vram range mapping. */
+void
+dirty_vram_delete_shadow(struct vcpu *v,
+                         unsigned long gfn,
+                         unsigned int shadow_type, 
+                         mfn_t smfn)
+{
+    static unsigned int l1_shadow_mask = 
+          1 << SH_type_l1_32_shadow
+        | 1 << SH_type_fl1_32_shadow
+        | 1 << SH_type_l1_pae_shadow
+        | 1 << SH_type_fl1_pae_shadow
+        | 1 << SH_type_l1_64_shadow
+        | 1 << SH_type_fl1_64_shadow
+        ;
+    struct domain *d = v->domain;
+    dv_dirty_vram_t *dirty_vram;
+    struct list_head *curr, *next;
+    dv_paddr_link_t *pl = NULL;
+    paddr_t *ppl = NULL;
+    
+    ASSERT(paging_locked_by_me(d));
+    /* Ignore all but level 1 shadows */
+    
+    if ( (l1_shadow_mask & (1 << shadow_type)) == 0 )
     {
-        rc = 0;
         goto out;
     }
 
-    /* This should happen seldomly (Video mode change),
-     * no need to be careful. */
+    dirty_vram = d->arch.hvm_domain.dirty_vram;
     if ( !dirty_vram )
     {
-        /* Throw away all the shadows rather than walking through them 
-         * up to nr times getting rid of mappings of each pfn */
-        shadow_blow_tables(d);
-
-        gdprintk(XENLOG_INFO, "tracking VRAM %lx - %lx\n", begin_pfn,
end_pfn);
-
-        rc = -ENOMEM;
-        if ( (dirty_vram = xmalloc(struct sh_dirty_vram)) == NULL )
-            goto out;
-        dirty_vram->begin_pfn = begin_pfn;
-        dirty_vram->end_pfn = end_pfn;
-        d->arch.hvm_domain.dirty_vram = dirty_vram;
-
-        if ( (dirty_vram->sl1ma = xmalloc_array(paddr_t, nr)) == NULL )
-            goto out_dirty_vram;
-        memset(dirty_vram->sl1ma, ~0, sizeof(paddr_t) * nr);
-
-        if ( (dirty_vram->dirty_bitmap = xzalloc_array(uint8_t, dirty_size))
== NULL )
-            goto out_sl1ma;
-
-        dirty_vram->last_dirty = NOW();
-
-        /* Tell the caller that this time we could not track dirty bits. */
-        rc = -ENODATA;
-    }
-    else if (dirty_vram->last_dirty == -1)
-    {
-        /* still completely clean, just copy our empty bitmap */
-        rc = -EFAULT;
-        if ( copy_to_guest(dirty_bitmap, dirty_vram->dirty_bitmap,
dirty_size) == 0 )
-            rc = 0;
+        goto out;
     }
-    else
+        
+    list_for_each_safe(curr, next, &dirty_vram->range_head)
     {
-        unsigned long map_mfn = INVALID_MFN;
-        void *map_sl1p = NULL;
-
-        /* Iterate over VRAM to track dirty bits. */
-        for ( i = 0; i < nr; i++ ) {
-            mfn_t mfn = get_gfn_query_unlocked(d, begin_pfn + i, &t);
-            struct page_info *page;
-            int dirty = 0;
-            paddr_t sl1ma = dirty_vram->sl1ma[i];
+        dv_range_t *range = list_entry(curr, dv_range_t, range_link);
+        unsigned long i;
+        int max_mappings = 1, mappings = 0;
+        int unshadowed = 0;
+        for ( i = 0; i != range->end_pfn - range->begin_pfn; i++ )
+        {
+            
+            pl = remap_vaddr(pl, &range->pl_tab[ i ].mapping);
+            /* clean up from previous iteration */
+            ppl = remap_vaddr(ppl, NULL); /* unmap ppl */
 
-            if (mfn_x(mfn) == INVALID_MFN)
-            {
-                dirty = 1;
-            }
-            else
+            mappings = 0;
+            
+            while ( pl != NULL )
             {
-                page = mfn_to_page(mfn);
-                switch (page->u.inuse.type_info & PGT_count_mask)
-                {
-                case 0:
-                    /* No guest reference, nothing to track. */
-                    break;
-                case 1:
-                    /* One guest reference. */
-                    if ( sl1ma == INVALID_PADDR )
-                    {
-                        /* We don''t know which sl1e points to this,
too bad. */
-                        dirty = 1;
-                        /* TODO: Heuristics for finding the single mapping of
-                         * this gmfn */
-                        flush_tlb |= sh_remove_all_mappings(d->vcpu[0],
mfn);
-                    }
-                    else
-                    {
-                        /* Hopefully the most common case: only one mapping,
-                         * whose dirty bit we can use. */
-                        l1_pgentry_t *sl1e;
-                        unsigned long sl1mfn = paddr_to_pfn(sl1ma);
-
-                        if ( sl1mfn != map_mfn )
-                        {
-                            if ( map_sl1p )
-                                sh_unmap_domain_page(map_sl1p);
-                            map_sl1p = sh_map_domain_page(_mfn(sl1mfn));
-                            map_mfn = sl1mfn;
-                        }
-                        sl1e = map_sl1p + (sl1ma & ~PAGE_MASK);
-
-                        if ( l1e_get_flags(*sl1e) & _PAGE_DIRTY )
-                        {
-                            dirty = 1;
-                            /* Note: this is atomic, so we may clear a
-                             * _PAGE_ACCESSED set by another processor. */
-                            l1e_remove_flags(*sl1e, _PAGE_DIRTY);
-                            flush_tlb = 1;
-                        }
-                    }
-                    break;
-                default:
-                    /* More than one guest reference,
-                     * we don''t afford tracking that. */
-                    dirty = 1;
+                paddr_t sl1ma = pl->sl1ma;
+                unsigned long sl1mn;
+               
+                if ( sl1ma == INVALID_PADDR )
                     break;
+                
+                sl1mn = sl1ma >> PAGE_SHIFT;
+                if ( sl1mn == mfn_x(smfn) ) {
+#if DEBUG_unshadow_sl1ma_detail
+                    gdprintk(XENLOG_DEBUG,
+                             "[%lx] gfn[%lx] unshadow sl1ma:%lx\n",
+                             mfn_x(smfn),
+                             range->begin_pfn + i,
+                             sl1ma);
+#endif
+                    unshadowed++;
+                    pl = free_paddr_link(d, ppl, pl);
+                    /* ppl remains unchanged. */
+                }
+                else
+                {
+                    ppl = remap_vaddr(ppl, &pl->pl_next);
+                    pl =  remap_maddr(pl, (*ppl));
+                    mappings++;
                 }
-            }
-
-            if ( dirty )
-            {
-                dirty_vram->dirty_bitmap[i / 8] |= 1 << (i % 8);
-                dirty_vram->last_dirty = NOW();
             }
         }
+        if ( mappings > max_mappings )
+            max_mappings = mappings;
+        
+        if ( unshadowed ) {
+#if DEBUG_unshadow_sl1ma
+            gdprintk(XENLOG_DEBUG,
+                     "[%lx] gfn[%05lx:%05lx] unshadowed:%d mappings:0x%x
"
+                     "max_mappings:%d\n",
+                     mfn_x(smfn),
+                     range->begin_pfn, range->end_pfn,
+                     unshadowed, range->nr_mappings, max_mappings);
+#endif
+        }
+    }
+ out:
+    remap_vaddr(pl,  NULL); /* unmap pl */
+    remap_vaddr(ppl, NULL); /* unmap ppl */
+    return;
+}
+
 
-        if ( map_sl1p )
-            sh_unmap_domain_page(map_sl1p);
+typedef int (*hash_pfn_callback_t)(struct vcpu *v,
+                                   mfn_t smfn,
+                                   unsigned long begin_pfn,
+                                   unsigned long end_pfn,
+                                   int *removed);
 
-        rc = -EFAULT;
-        if ( copy_to_guest(dirty_bitmap, dirty_vram->dirty_bitmap,
dirty_size) == 0 ) {
-            memset(dirty_vram->dirty_bitmap, 0, dirty_size);
-            if (dirty_vram->last_dirty + SECONDS(2) < NOW())
+static int hash_pfn_foreach(struct vcpu *v, 
+                            unsigned int callback_mask, 
+                            hash_pfn_callback_t callbacks[], 
+                            unsigned long begin_pfn,
+                            unsigned long end_pfn)
+/* Walk the hash table looking at the types of the entries and 
+ * calling the appropriate callback function for each entry. 
+ * The mask determines which shadow types we call back for, and the array
+ * of callbacks tells us which function to call.
+ * Any callback may return non-zero to let us skip the rest of the scan. 
+ *
+ * WARNING: Callbacks MUST NOT add or remove hash entries unless they 
+ * then return non-zero to terminate the scan. */
+{
+    int i, done = 0, removed = 0;
+    struct domain *d = v->domain;
+    struct page_info *x;
+
+    /* Say we''re here, to stop hash-lookups reordering the chains */
+    ASSERT(paging_locked_by_me(d));
+    ASSERT(d->arch.paging.shadow.hash_walking == 0);
+    d->arch.paging.shadow.hash_walking = 1;
+
+    for ( i = 0; i < SHADOW_HASH_BUCKETS; i++ ) 
+    {
+        /* WARNING: This is not safe against changes to the hash table.
+         * The callback *must* return non-zero if it has inserted or
+         * deleted anything from the hash (lookups are OK, though). */
+        for ( x = d->arch.paging.shadow.hash_table[i];
+              x;
+              x = next_shadow(x) )
+        {
+            if ( callback_mask & (1 << x->u.sh.type) )
             {
-                /* was clean for more than two seconds, try to disable guest
-                 * write access */
-                for ( i = begin_pfn; i < end_pfn; i++ ) {
-                    mfn_t mfn = get_gfn_query_unlocked(d, i, &t);
-                    if (mfn_x(mfn) != INVALID_MFN)
-                        flush_tlb |= sh_remove_write_access(d->vcpu[0], mfn,
1, 0);
-                }
-                dirty_vram->last_dirty = -1;
+                ASSERT(x->u.sh.type <= 15);
+                ASSERT(callbacks[x->u.sh.type] != NULL);
+                done = callbacks[x->u.sh.type](v, page_to_mfn(x), 
+                                               begin_pfn, end_pfn,
+                                               &removed);
+                if ( done ) break;
             }
-            rc = 0;
         }
+        if ( done ) break; 
     }
-    if ( flush_tlb )
-        flush_tlb_mask(d->domain_dirty_cpumask);
-    goto out;
+    d->arch.paging.shadow.hash_walking = 0;
+    return removed;
+}
+
+void sh_find_all_vram_mappings(struct vcpu *v,
+                               dv_range_t *range)
+{
+    /* Dispatch table for getting per-type functions */
+    static hash_pfn_callback_t callbacks[SH_type_unused] = {
+        NULL, /* none    */
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 2), /* l1_32   */
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 2), /* fl1_32  */
+        NULL, /* l2_32   */
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 3), /* l1_pae  */
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 3), /* fl1_pae */
+        NULL, /* l2_pae  */
+        NULL, /* l2h_pae */
+#if CONFIG_PAGING_LEVELS >= 4
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 4), /* l1_64   */
+        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 4), /* fl1_64  */
+#else
+        NULL, /* l1_64   */
+        NULL, /* fl1_64  */
+#endif
+        NULL, /* l2_64   */
+        NULL, /* l2h_64  */
+        NULL, /* l3_64   */
+        NULL, /* l4_64   */
+        NULL, /* p2m     */
+        NULL  /* unused  */
+    };
 
-out_sl1ma:
-    xfree(dirty_vram->sl1ma);
-out_dirty_vram:
-    xfree(dirty_vram);
-    dirty_vram = d->arch.hvm_domain.dirty_vram = NULL;
+    static unsigned int callback_mask = 
+          1 << SH_type_l1_32_shadow
+        | 1 << SH_type_fl1_32_shadow
+        | 1 << SH_type_l1_pae_shadow
+        | 1 << SH_type_fl1_pae_shadow
+        | 1 << SH_type_l1_64_shadow
+        | 1 << SH_type_fl1_64_shadow
+        ;
 
-out:
-    paging_unlock(d);
-    p2m_unlock(p2m_get_hostp2m(d));
-    return rc;
+    perfc_incr(shadow_mappings);
+
+    hash_pfn_foreach(v, callback_mask, callbacks,
+                     range->begin_pfn,
+                     range->end_pfn);
+
+#if DEBUG_count_initial_mappings
+    gdprintk(XENLOG_DEBUG, "[%05lx:%05lx] count of initial\n",
+             range->begin_pfn, range->end_pfn
+#endif
 }
 
+
 /**************************************************************************/
 /* Shadow-control XEN_DOMCTL dispatcher */
 
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index b79cd6c..922e01a 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -35,6 +35,7 @@
 #include <asm/flushtlb.h>
 #include <asm/hvm/hvm.h>
 #include <asm/hvm/cacheattr.h>
+#include <asm/dirty_vram.h>
 #include <asm/mtrr.h>
 #include <asm/guest_pt.h>
 #include <public/sched.h>
@@ -149,6 +150,10 @@ delete_fl1_shadow_status(struct vcpu *v, gfn_t gfn, mfn_t
smfn)
     SHADOW_PRINTK("gfn=%"SH_PRI_gfn", type=%08x,
smfn=%05lx\n",
                    gfn_x(gfn), SH_type_fl1_shadow, mfn_x(smfn));
     ASSERT(mfn_to_page(smfn)->u.sh.head);
+
+    /* Removing any dv_paddr_links to the erstwhile shadow page */
+    dirty_vram_delete_shadow(v, gfn_x(gfn), SH_type_fl1_shadow, smfn);
+    
     shadow_hash_delete(v, gfn_x(gfn), SH_type_fl1_shadow, smfn);
 }
 
@@ -160,6 +165,10 @@ delete_shadow_status(struct vcpu *v, mfn_t gmfn, u32
shadow_type, mfn_t smfn)
                    v->domain->domain_id, v->vcpu_id,
                    mfn_x(gmfn), shadow_type, mfn_x(smfn));
     ASSERT(mfn_to_page(smfn)->u.sh.head);
+    
+    /* Removing any dv_paddr_links to the erstwhile shadow page */
+    dirty_vram_delete_shadow(v, mfn_x(gmfn), shadow_type, smfn);
+    
     shadow_hash_delete(v, mfn_x(gmfn), shadow_type, smfn);
     /* 32-on-64 PV guests don''t own their l4 pages; see
set_shadow_status */
     if ( !is_pv_32on64_vcpu(v) || shadow_type != SH_type_l4_64_shadow )
@@ -516,7 +525,6 @@ _sh_propagate(struct vcpu *v,
     guest_l1e_t guest_entry = { guest_intpte };
     shadow_l1e_t *sp = shadow_entry_ptr;
     struct domain *d = v->domain;
-    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
     gfn_t target_gfn = guest_l1e_get_gfn(guest_entry);
     u32 pass_thru_flags;
     u32 gflags, sflags;
@@ -663,17 +671,6 @@ _sh_propagate(struct vcpu *v,
         }
     }
 
-    if ( unlikely((level == 1) && dirty_vram
-            && dirty_vram->last_dirty == -1
-            && gfn_x(target_gfn) >= dirty_vram->begin_pfn
-            && gfn_x(target_gfn) < dirty_vram->end_pfn) )
-    {
-        if ( ft & FETCH_TYPE_WRITE )
-            dirty_vram->last_dirty = NOW();
-        else
-            sflags &= ~_PAGE_RW;
-    }
-
     /* Read-only memory */
     if ( p2m_is_readonly(p2mt) ||
          (p2mt == p2m_mmio_direct &&
@@ -1072,101 +1069,60 @@ static int shadow_set_l2e(struct vcpu *v,
     return flags;
 }
 
-static inline void shadow_vram_get_l1e(shadow_l1e_t new_sl1e,
+/* shadow_vram_fix_l1e()
+ *
+ * Tests L1PTEs as they are modified, looking for when they start to (or
+ * cease to) point to frame buffer pages.  If the old and new gfns differ,
+ * calls dirty_vram_range_update() to updates the dirty_vram structures.
+ */
+static inline void shadow_vram_fix_l1e(shadow_l1e_t old_sl1e,
+                                       shadow_l1e_t new_sl1e,
                                        shadow_l1e_t *sl1e,
                                        mfn_t sl1mfn,
                                        struct domain *d)
 { 
-    mfn_t mfn = shadow_l1e_get_mfn(new_sl1e);
-    int flags = shadow_l1e_get_flags(new_sl1e);
-    unsigned long gfn;
-    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
+    mfn_t new_mfn, old_mfn;
+    unsigned long new_gfn = INVALID_M2P_ENTRY, old_gfn = INVALID_M2P_ENTRY;
+    paddr_t sl1ma;
+    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
 
-    if ( !dirty_vram         /* tracking disabled? */
-         || !(flags & _PAGE_RW) /* read-only mapping? */
-         || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
+    if ( !dirty_vram )
         return;
 
-    gfn = mfn_to_gfn(d, mfn);
-    /* Page sharing not supported on shadow PTs */
-    BUG_ON(SHARED_M2P(gfn));
+    sl1ma = pfn_to_paddr(mfn_x(sl1mfn)) | ((unsigned long)sl1e &
~PAGE_MASK);
 
-    if ( (gfn >= dirty_vram->begin_pfn) && (gfn <
dirty_vram->end_pfn) )
+    old_mfn = shadow_l1e_get_mfn(old_sl1e);
+
+    if ( !sh_l1e_is_magic(old_sl1e) &&
+         (l1e_get_flags(old_sl1e) & _PAGE_PRESENT) &&
+         mfn_valid(old_mfn))
     {
-        unsigned long i = gfn - dirty_vram->begin_pfn;
-        struct page_info *page = mfn_to_page(mfn);
-        
-        if ( (page->u.inuse.type_info & PGT_count_mask) == 1 )
-            /* Initial guest reference, record it */
-            dirty_vram->sl1ma[i] = pfn_to_paddr(mfn_x(sl1mfn))
-                | ((unsigned long)sl1e & ~PAGE_MASK);
+        old_gfn = mfn_to_gfn(d, old_mfn);
     }
-}
-
-static inline void shadow_vram_put_l1e(shadow_l1e_t old_sl1e,
-                                       shadow_l1e_t *sl1e,
-                                       mfn_t sl1mfn,
-                                       struct domain *d)
-{
-    mfn_t mfn = shadow_l1e_get_mfn(old_sl1e);
-    int flags = shadow_l1e_get_flags(old_sl1e);
-    unsigned long gfn;
-    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
-
-    if ( !dirty_vram         /* tracking disabled? */
-         || !(flags & _PAGE_RW) /* read-only mapping? */
-         || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
-        return;
-
-    gfn = mfn_to_gfn(d, mfn);
-    /* Page sharing not supported on shadow PTs */
-    BUG_ON(SHARED_M2P(gfn));
-
-    if ( (gfn >= dirty_vram->begin_pfn) && (gfn <
dirty_vram->end_pfn) )
+    
+    new_mfn = shadow_l1e_get_mfn(new_sl1e);
+    if ( !sh_l1e_is_magic(new_sl1e) &&
+         (l1e_get_flags(new_sl1e) & _PAGE_PRESENT) &&
+         mfn_valid(new_mfn))
     {
-        unsigned long i = gfn - dirty_vram->begin_pfn;
-        struct page_info *page = mfn_to_page(mfn);
-        int dirty = 0;
-        paddr_t sl1ma = pfn_to_paddr(mfn_x(sl1mfn))
-            | ((unsigned long)sl1e & ~PAGE_MASK);
+        new_gfn = mfn_to_gfn(d, new_mfn);
+    }
 
-        if ( (page->u.inuse.type_info & PGT_count_mask) == 1 )
-        {
-            /* Last reference */
-            if ( dirty_vram->sl1ma[i] == INVALID_PADDR ) {
-                /* We didn''t know it was that one, let''s say
it is dirty */
-                dirty = 1;
-            }
-            else
-            {
-                ASSERT(dirty_vram->sl1ma[i] == sl1ma);
-                dirty_vram->sl1ma[i] = INVALID_PADDR;
-                if ( flags & _PAGE_DIRTY )
-                    dirty = 1;
-            }
-        }
-        else
+    if ( old_gfn == new_gfn ) return;
+
+    if ( VALID_M2P(old_gfn) )
+        if ( dirty_vram_range_update(d, old_gfn, sl1ma, 0/*clear*/) )
         {
-            /* We had more than one reference, just consider the page dirty. */
-            dirty = 1;
-            /* Check that it''s not the one we recorded. */
-            if ( dirty_vram->sl1ma[i] == sl1ma )
-            {
-                /* Too bad, we remembered the wrong one... */
-                dirty_vram->sl1ma[i] = INVALID_PADDR;
-            }
-            else
-            {
-                /* Ok, our recorded sl1e is still pointing to this page,
let''s
-                 * just hope it will remain. */
-            }
+            SHADOW_PRINTK("gfn %lx (mfn %lx) cleared vram pte\n",
+                          old_gfn, mfn_x(old_mfn));
         }
-        if ( dirty )
+
+    if ( VALID_M2P(new_gfn) )
+        if ( dirty_vram_range_update(d, new_gfn, sl1ma, 1/*set*/) )
         {
-            dirty_vram->dirty_bitmap[i / 8] |= 1 << (i % 8);
-            dirty_vram->last_dirty = NOW();
+            SHADOW_PRINTK("gfn %lx (mfn %lx) set vram pte\n",
+                          new_gfn, mfn_x(new_mfn));
         }
-    }
 }
 
 static int shadow_set_l1e(struct vcpu *v, 
@@ -1211,12 +1167,13 @@ static int shadow_set_l1e(struct vcpu *v,
                 shadow_l1e_remove_flags(new_sl1e, _PAGE_RW);
                 /* fall through */
             case 0:
-                shadow_vram_get_l1e(new_sl1e, sl1e, sl1mfn, d);
                 break;
             }
         }
     } 
 
+    shadow_vram_fix_l1e(old_sl1e, new_sl1e, sl1e, sl1mfn, d);
+
     /* Write the new entry */
     shadow_write_entries(sl1e, &new_sl1e, 1, sl1mfn);
     flags |= SHADOW_SET_CHANGED;
@@ -1231,7 +1188,6 @@ static int shadow_set_l1e(struct vcpu *v,
          * trigger a flush later. */
         if ( shadow_mode_refcounts(d) ) 
         {
-            shadow_vram_put_l1e(old_sl1e, sl1e, sl1mfn, d);
             shadow_put_page_from_l1e(old_sl1e, d);
             TRACE_SHADOW_PATH_FLAG(TRCE_SFLAG_SHADOW_L1_PUT_REF);
         } 
@@ -2018,7 +1974,6 @@ void sh_destroy_l1_shadow(struct vcpu *v, mfn_t smfn)
         SHADOW_FOREACH_L1E(sl1mfn, sl1e, 0, 0, {
             if ( (shadow_l1e_get_flags(*sl1e) & _PAGE_PRESENT)
                  && !sh_l1e_is_magic(*sl1e) ) {
-                shadow_vram_put_l1e(*sl1e, sl1e, sl1mfn, d);
                 shadow_put_page_from_l1e(*sl1e, d);
             }
         });
@@ -4336,6 +4291,37 @@ int sh_rm_mappings_from_l1(struct vcpu *v, mfn_t sl1mfn,
mfn_t target_mfn)
     return done;
 }
 
+
+int sh_find_vram_mappings_in_l1(struct vcpu *v,
+                                mfn_t sl1mfn,
+                                unsigned long begin_pfn,
+                                unsigned long end_pfn,
+                                int *removed)
+/* Find all VRAM mappings in this shadow l1 table */
+{
+    struct domain *d = v->domain;
+    shadow_l1e_t *sl1e;
+    int done = 0;
+
+    /* only returns _PAGE_PRESENT entries */
+    SHADOW_FOREACH_L1E(sl1mfn, sl1e, 0, done, 
+    {
+        unsigned long gfn;
+        mfn_t gmfn = shadow_l1e_get_mfn(*sl1e);
+        if ( !mfn_valid(gmfn) )
+            continue;
+        gfn = mfn_to_gfn(d, gmfn);
+        if ( VALID_M2P(gfn) && (begin_pfn <= gfn) && (gfn
< end_pfn) )
+        {
+            paddr_t sl1ma +                pfn_to_paddr(mfn_x(sl1mfn)) |
+                ( (unsigned long)sl1e & ~PAGE_MASK );
+            dirty_vram_range_update(v->domain, gfn, sl1ma, 1/*set*/);
+        }
+    });
+    return 0;
+}
+
 /**************************************************************************/
 /* Functions to excise all pointers to shadows from higher-level shadows. */
 
diff --git a/xen/arch/x86/mm/shadow/multi.h b/xen/arch/x86/mm/shadow/multi.h
index 835121e..436a4ac 100644
--- a/xen/arch/x86/mm/shadow/multi.h
+++ b/xen/arch/x86/mm/shadow/multi.h
@@ -66,7 +66,12 @@ SHADOW_INTERNAL_NAME(sh_rm_write_access_from_l1,
GUEST_LEVELS)
 extern int
 SHADOW_INTERNAL_NAME(sh_rm_mappings_from_l1, GUEST_LEVELS)
     (struct vcpu *v, mfn_t sl1mfn, mfn_t target_mfn);
-
+extern int
+SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, GUEST_LEVELS)
+     (struct vcpu *v, mfn_t sl1mfn, 
+      unsigned long begin_pfn,
+      unsigned long end_pfn,
+      int *removed);
 extern void
 SHADOW_INTERNAL_NAME(sh_clear_shadow_entry, GUEST_LEVELS)
     (struct vcpu *v, void *ep, mfn_t smfn);
diff --git a/xen/arch/x86/mm/shadow/types.h b/xen/arch/x86/mm/shadow/types.h
index 43ce1db..5b0f9f7 100644
--- a/xen/arch/x86/mm/shadow/types.h
+++ b/xen/arch/x86/mm/shadow/types.h
@@ -229,6 +229,7 @@ static inline shadow_l4e_t shadow_l4e_from_mfn(mfn_t mfn,
u32 flags)
 #define sh_update_cr3              INTERNAL_NAME(sh_update_cr3)
 #define sh_rm_write_access_from_l1 INTERNAL_NAME(sh_rm_write_access_from_l1)
 #define sh_rm_mappings_from_l1     INTERNAL_NAME(sh_rm_mappings_from_l1)
+#define sh_find_vram_mappings_in_l1 INTERNAL_NAME(sh_find_vram_mappings_in_l1)
 #define sh_remove_l1_shadow        INTERNAL_NAME(sh_remove_l1_shadow)
 #define sh_remove_l2_shadow        INTERNAL_NAME(sh_remove_l2_shadow)
 #define sh_remove_l3_shadow        INTERNAL_NAME(sh_remove_l3_shadow)
diff --git a/xen/include/asm-x86/dirty_vram.h b/xen/include/asm-x86/dirty_vram.h
new file mode 100644
index 0000000..727af05
--- /dev/null
+++ b/xen/include/asm-x86/dirty_vram.h
@@ -0,0 +1,227 @@
+/****************************************************************************
+ * include/asm-x86/dirty_vram.h
+ *
+ * Interface for tracking dirty VRAM pages
+ *
+ * Copyright (c) 2012 Citrix Systems, Inc. (Robert Phillips)
+ * Parts of this code are Copyright (c) 2007 Advanced Micro Devices (Wei Huang)
+ * Parts of this code are Copyright (c) 2006 by XenSource Inc.
+ * Parts of this code are Copyright (c) 2006 by Michael A Fetterman
+ * Parts based on earlier work by Michael A Fetterman, Ian Pratt et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _DIRTY_VRAM_H
+#define _DIRTY_VRAM_H
+
+/*
+ * In shadow mode we need to bookkeep all the L1 page table entries that
+ * map a frame buffer page.  Struct dv_paddr_link does this by
+ * recording the address of a L1 page table entry for some frame buffer page.
+ * Also has a link to additional pl entries if the frame buffer page
+ * has multiple mappings.
+ * In practice very few pages have multiple mappings.
+ * But to rule out some pathological situation, we limit the number of
+ * mappings we''re willing to bookkeep.
+ */
+
+#define DV_ADDR_LINK_LIST_LIMIT 64
+
+typedef struct dv_paddr_link {
+    paddr_t sl1ma;
+    paddr_t pl_next;
+} dv_paddr_link_t;
+
+typedef struct dv_pl_entry {
+    dv_paddr_link_t mapping;
+    bool_t stuck_dirty;
+} dv_pl_entry_t;
+
+/*
+ * This defines an extension page of pl entries for FB pages with multiple
+ * mappings. All such pages (of a domain) are linked together.
+ */
+typedef struct dv_paddr_link_ext {
+    paddr_t ext_link;
+    dv_paddr_link_t entries[ ( PAGE_SIZE - sizeof( paddr_t ) ) /
+                             sizeof( dv_paddr_link_t ) ];
+} dv_paddr_link_ext_t;
+
+/*
+ * This defines a single frame buffer range.  It bookkeeps all the
+ * level 1 PTEs that map guest pages within that range.
+ * All such ranges (of a domain) are linked together.
+ */
+typedef struct dv_range {
+    struct list_head range_link; /* the several ranges form a linked list */
+    unsigned long begin_pfn;
+    unsigned long end_pfn;
+    dv_pl_entry_t *pl_tab; /* table has 1 pl entry per pfn in range */
+    int mappings_hwm; /* high water mark of max mapping count */
+    unsigned int dirty_count;
+} dv_range_t;
+
+/*
+ * This contains all the data structures required by a domain to
+ * bookkeep the dirty pages within its frame buffers.
+ */
+typedef struct dv_dirty_vram {
+    struct list_head range_head; /* head of the linked list of ranges */
+    paddr_t ext_head;/* head of list of extension pages */
+    paddr_t pl_free; /* free list of pl''s within extension pages */
+    int nr_ranges;   /* bookkeeps number of ranges */
+    int ranges_hwm;  /* high water mark of max number of ranges */
+} dv_dirty_vram_t;
+
+/* Allocates domain''s dirty_vram structure */
+dv_dirty_vram_t *
+dirty_vram_alloc(struct domain *d);
+
+/*
+ * Returns domain''s dirty_vram structure,
+ * allocating it if necessary
+ */
+dv_dirty_vram_t *
+dirty_vram_find_or_alloc(struct domain *d);
+
+/* Frees domain''s dirty_vram structure */
+void dirty_vram_free(struct domain *d);
+
+/* Returns dirty vram range containing gfn, NULL if none */
+struct dv_range *
+dirty_vram_range_find_gfn(struct domain *d,
+                          unsigned long gfn);
+
+/*
+ * Returns dirty vram range matching [ begin_pfn .. begin_pfn+nr ),
+ * NULL if none
+ */
+dv_range_t *
+dirty_vram_range_find(struct domain *d,
+                      unsigned long begin_pfn,
+                      unsigned long nr);
+
+/*
+ * Allocate dirty vram range containing [ begin_pfn .. begin_pfn+nr ),
+ * freeing any existing range that overlaps the new range.
+ */
+dv_range_t *
+dirty_vram_range_alloc(struct domain *d,
+                       unsigned long begin_pfn,
+                       unsigned long nr);
+
+/*
+ * Returns dirty vram range matching [ begin_pfn .. begin_pfn+nr ),
+ * creating a range if none already exists and
+ * freeing any existing range that overlaps the new range.
+ */
+dv_range_t *
+dirty_vram_range_find_or_alloc(struct domain *d,
+                               unsigned long begin_pfn,
+                               unsigned long nr);
+
+void dirty_vram_range_free(struct domain *d,
+                           dv_range_t *range);
+
+/* Bookkeep PTE address of a frame buffer page */
+int dirty_vram_range_update(struct domain *d,
+                            unsigned long gfn,
+                            paddr_t sl1ma,
+                            int set);
+
+/*
+ * smfn is no longer a shadow page.  Remove it from any
+ * dirty vram range mapping.
+ */
+void
+dirty_vram_delete_shadow(struct vcpu *v,
+                         unsigned long gfn,
+                         unsigned int shadow_type,
+                         mfn_t smfn);
+
+
+/*
+ * Scan all the L1 tables looking for VRAM mappings.
+ * Record them in the domain''s dv_dirty_vram structure
+ */
+void sh_find_all_vram_mappings(struct vcpu *v,
+                               dv_range_t *range);
+
+/*
+ * Free a paddr_link struct, given address of its
+ * predecessor in singly-linked list
+ */
+dv_paddr_link_t *
+free_paddr_link(struct domain *d,
+                paddr_t* ppl,
+                dv_paddr_link_t *pl);
+
+
+/* Enable VRAM dirty tracking. */
+int
+shadow_track_dirty_vram(struct domain *d,
+                        unsigned long first_pfn,
+                        unsigned long nr,
+                        XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
+
+int
+hap_track_dirty_vram(struct domain *d,
+                     unsigned long begin_pfn,
+                     unsigned long nr,
+                     XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
+
+void
+hap_clean_vram_tracking_range(struct domain *d,
+                              unsigned long begin_pfn,
+                              unsigned long nr,
+                              uint8_t *dirty_bitmap);
+
+/* Unmap a va and map a ma.
+ * This is used when walking a linked list in which
+ * the links are stored as ma''s rather than va''s.
+ * Each step in the walk unmaps the va returned
+ * by the previous iteration and maps the next link.
+ *
+ * Unmaps @old_va if not NULL.
+ *
+ * If @new_va is not INVALID_PADDR, maps it and returns the resulting
+ * va (which must be subsequently unmapped.) Else returns NULL.
+ */
+void *
+remap_maddr(void *old_va, paddr_t new_ma);
+
+
+/* Like the above but it acquires a mapping
+ * (possibly an additional mapping) on @new_va.
+ *
+ * Returns @new_va.
+ *
+ * Does no unmapping if @old_va is NULL.
+ * Does no mapping if @new_va is NULL.
+ */
+void *
+remap_vaddr(void *old_va, void *new_va);
+
+#endif /* _DIRTY_VRAM_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-x86/hap.h b/xen/include/asm-x86/hap.h
index 916a35b..3e3a1f5 100644
--- a/xen/include/asm-x86/hap.h
+++ b/xen/include/asm-x86/hap.h
@@ -57,10 +57,6 @@ void  hap_final_teardown(struct domain *d);
 void  hap_teardown(struct domain *d);
 void  hap_vcpu_init(struct vcpu *v);
 void  hap_logdirty_init(struct domain *d);
-int   hap_track_dirty_vram(struct domain *d,
-                           unsigned long begin_pfn,
-                           unsigned long nr,
-                           XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
 
 extern const struct paging_mode *hap_paging_get_mode(struct vcpu *);
 
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 27b3de5..0cc7b05 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -74,7 +74,7 @@ struct hvm_domain {
     struct list_head       pinned_cacheattr_ranges;
 
     /* VRAM dirty support. */
-    struct sh_dirty_vram *dirty_vram;
+    struct dv_dirty_vram  *dirty_vram;
 
     /* If one of vcpus of this domain is in no_fill_mode or
      * mtrr/pat between vcpus is not the same, set is_in_uc_mode
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index c3a8848..e22df38 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -154,9 +154,13 @@ void paging_log_dirty_init(struct domain *d,
                            int  (*disable_log_dirty)(struct domain *d),
                            void (*clean_dirty_bitmap)(struct domain *d));
 
-/* mark a page as dirty */
+/* mark a gmfn as dirty, a wrapper around marking a gpfn as dirty */
 void paging_mark_dirty(struct domain *d, unsigned long guest_mfn);
 
+/* mark a gpfn as dirty */
+void paging_mark_dirty_gpfn(struct domain *d, unsigned long gpfn);
+
+
 /* is this guest page dirty? 
  * This is called from inside paging code, with the paging lock held. */
 int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
@@ -183,15 +187,6 @@ int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
 #define L4_LOGDIRTY_IDX(pfn) 0
 #endif
 
-/* VRAM dirty tracking support */
-struct sh_dirty_vram {
-    unsigned long begin_pfn;
-    unsigned long end_pfn;
-    paddr_t *sl1ma;
-    uint8_t *dirty_bitmap;
-    s_time_t last_dirty;
-};
-
 /*****************************************************************************
  * Entry points into the paging-assistance code */
 
diff --git a/xen/include/asm-x86/shadow.h b/xen/include/asm-x86/shadow.h
index 2eb6efc..940d7fd 100644
--- a/xen/include/asm-x86/shadow.h
+++ b/xen/include/asm-x86/shadow.h
@@ -62,12 +62,6 @@ void shadow_vcpu_init(struct vcpu *v);
 /* Enable an arbitrary shadow mode.  Call once at domain creation. */
 int shadow_enable(struct domain *d, u32 mode);
 
-/* Enable VRAM dirty bit tracking. */
-int shadow_track_dirty_vram(struct domain *d,
-                            unsigned long first_pfn,
-                            unsigned long nr,
-                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
-
 /* Handler for shadow control ops: operations from user-space to enable
  * and disable ephemeral shadow modes (test mode and log-dirty mode) and
  * manipulate the log-dirty bitmap. */
-- 
1.7.9.5

On Fri, Mar 01, 2013 at 03:48:57PM -0500, Robert Phillips
wrote:
> Support is provided for both shadow and hardware assisted paging (HAP)
> modes. This code bookkeeps the set of video frame buffers (vram),
> detects when the guest has modified any of those buffers and, upon request,
> returns a bitmap of the modified pages.
> This lets other software components re-paint the portions of the monitor
> (or monitors) that have changed.
> Each monitor has a frame buffer of some size at some position
> in guest physical memory.
> The set of frame buffers being tracked can change over time as monitors
> are plugged and unplugged.
> 
> This is the 9th version of this patch.
>
It''d be nice to have it in the subject of the email aswell..

-- Pasi
> Signed-Off-By: Robert Phillips <robert.phillips@citrix.com>
> ---
>  tools/libxc/xenctrl.h            |   20 +-
>  xen/arch/x86/hvm/hvm.c           |    8 +-
>  xen/arch/x86/mm/Makefile         |    1 +
>  xen/arch/x86/mm/dirty_vram.c     |  951
++++++++++++++++++++++++++++++++++++++
>  xen/arch/x86/mm/hap/hap.c        |  111 -----
>  xen/arch/x86/mm/p2m.c            |   11 +-
>  xen/arch/x86/mm/paging.c         |   57 ++-
>  xen/arch/x86/mm/shadow/common.c  |  353 +++++++-------
>  xen/arch/x86/mm/shadow/multi.c   |  174 ++++---
>  xen/arch/x86/mm/shadow/multi.h   |    7 +-
>  xen/arch/x86/mm/shadow/types.h   |    1 +
>  xen/include/asm-x86/dirty_vram.h |  227 +++++++++
>  xen/include/asm-x86/hap.h        |    4 -
>  xen/include/asm-x86/hvm/domain.h |    2 +-
>  xen/include/asm-x86/paging.h     |   15 +-
>  xen/include/asm-x86/shadow.h     |    6 -
>  16 files changed, 1535 insertions(+), 413 deletions(-)
>  create mode 100644 xen/arch/x86/mm/dirty_vram.c
>  create mode 100644 xen/include/asm-x86/dirty_vram.h
> 
> diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
> index 32122fd..cd4e1ef 100644
> --- a/tools/libxc/xenctrl.h
> +++ b/tools/libxc/xenctrl.h
> @@ -1563,15 +1563,23 @@ int xc_hvm_inject_msi(
>      xc_interface *xch, domid_t dom, uint64_t addr, uint32_t data);
>  
>  /*
> - * Track dirty bit changes in the VRAM area
> + * Track dirty bit changes in a VRAM region defined by
> + * [ first_pfn : first_pfn + nr - 1 ]
>   *
>   * All of this is done atomically:
> - * - get the dirty bitmap since the last call
> - * - set up dirty tracking area for period up to the next call
> - * - clear the dirty tracking area.
> + * - gets the dirty bitmap since the last call, all zeroes for
> + *   the first call with some new region
> + * - sets up a dirty tracking region for period up to the next call
> + * - clears the specified dirty tracking region.
>   *
> - * Returns -ENODATA and does not fill bitmap if the area has changed since
the
> - * last call.
> + * Creating a new region causes any existing regions that it overlaps
> + * to be discarded.
> + *
> + * Specifying nr == 0 causes all regions to be discarded and
> + * disables dirty bit tracking.
> + *
> + * If nr is not a multiple of 64, only the first nr bits of bitmap
> + * are well defined.
>   */
>  int xc_hvm_track_dirty_vram(
>      xc_interface *xch, domid_t dom,
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index fcea52c..5a97ad3 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -57,6 +57,7 @@
>  #include <asm/hvm/cacheattr.h>
>  #include <asm/hvm/trace.h>
>  #include <asm/hvm/nestedhvm.h>
> +#include <asm/dirty_vram.h>
>  #include <asm/mtrr.h>
>  #include <asm/apic.h>
>  #include <public/sched.h>
> @@ -1447,8 +1448,11 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
>           */
>          if ( access_w )
>          {
> -            paging_mark_dirty(v->domain, mfn_x(mfn));
> -            p2m_change_type(v->domain, gfn, p2m_ram_logdirty,
p2m_ram_rw);
> +            if ( p2m_change_type(v->domain, gfn, p2m_ram_logdirty,
> +                                 p2m_ram_rw) == p2m_ram_logdirty )
> +            {
> +                paging_mark_dirty_gpfn(v->domain, gfn);
> +            }
>          }
>          rc = 1;
>          goto out_put_gfn;
> diff --git a/xen/arch/x86/mm/Makefile b/xen/arch/x86/mm/Makefile
> index 73dcdf4..becd0c9 100644
> --- a/xen/arch/x86/mm/Makefile
> +++ b/xen/arch/x86/mm/Makefile
> @@ -5,6 +5,7 @@ obj-y += paging.o
>  obj-y += p2m.o p2m-pt.o p2m-ept.o p2m-pod.o
>  obj-y += guest_walk_2.o
>  obj-y += guest_walk_3.o
> +obj-y += dirty_vram.o
>  obj-$(x86_64) += guest_walk_4.o
>  obj-$(x86_64) += mem_event.o
>  obj-$(x86_64) += mem_paging.o
> diff --git a/xen/arch/x86/mm/dirty_vram.c b/xen/arch/x86/mm/dirty_vram.c
> new file mode 100644
> index 0000000..4f599ed
> --- /dev/null
> +++ b/xen/arch/x86/mm/dirty_vram.c
> @@ -0,0 +1,951 @@
> +/*
> + * arch/x86/mm/dirty_vram.c: Bookkeep/query dirty VRAM pages
> + * with support for multiple frame buffers.
> + *
> + * Copyright (c) 2012, Citrix Systems, Inc. (Robert Phillips)
> + * Parts of this code are Copyright (c) 2007 Advanced Micro Devices (Wei
Huang)
> + * Parts of this code are Copyright (c) 2007 XenSource Inc.
> + * Parts of this code are Copyright (c) 2006 by Michael A Fetterman
> + * Parts based on earlier work by Michael A Fetterman, Ian Pratt et al.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along
with
> + * this program; if not, write to the Free Software Foundation, Inc., 59
Temple
> + * Place - Suite 330, Boston, MA 02111-1307 USA.
> + */
> +
> +
> +#include <xen/types.h>
> +#include <xen/sched.h>
> +#include <xen/guest_access.h>
> +#include <asm/shadow.h>
> +#include <asm/dirty_vram.h>
> +#include <asm/hap.h>
> +#include <asm/config.h>
> +#include "mm-locks.h"
> +
> +#define DEBUG_stop_tracking_all_vram          0
> +#define DEBUG_allocating_dirty_vram_range     0
> +#define DEBUG_high_water_mark_for_vram_ranges 0
> +#define DEBUG_freeing_dirty_vram_range        0
> +#define DEBUG_allocate_paddr_links_page       0
> +#define DEBUG_update_vram_mapping             0
> +#define DEBUG_alloc_paddr_inject_fault        0
> +#define DEBUG_link_limit_exceeded             0
> +
> +
> +/* Allocates domain''s dirty_vram structure */
> +dv_dirty_vram_t *
> +dirty_vram_alloc(struct domain *d)
> +{
> +    dv_dirty_vram_t *dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    dirty_vram = d->arch.hvm_domain.dirty_vram =
xzalloc(dv_dirty_vram_t);
> +    if ( dirty_vram )
> +    {
> +        INIT_LIST_HEAD(&dirty_vram->range_head);
> +        dirty_vram->ext_head = INVALID_PADDR;
> +        dirty_vram->pl_free = INVALID_PADDR;
> +    }
> +    return dirty_vram;
> +}
> +
> +/*
> + * Returns domain''s dirty_vram structure,
> + * allocating it if necessary
> + */
> +dv_dirty_vram_t *
> +dirty_vram_find_or_alloc(struct domain *d)
> +{
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    if ( !dirty_vram )
> +        dirty_vram = dirty_vram_alloc(d);
> +    return dirty_vram;
> +}
> +
> +
> +/* Free domain''s dirty_vram structure */
> +void dirty_vram_free(struct domain *d)
> +{
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    if ( dirty_vram )
> +    {
> +        struct list_head *curr, *next;
> +        dv_paddr_link_ext_t *ext;
> +        
> +        /* Free all the ranges */
> +        list_for_each_safe(curr, next, &dirty_vram->range_head)
> +        {
> +            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
> +#if DEBUG_stop_tracking_all_vram
> +            gdprintk(XENLOG_DEBUG, "[%05lx:%05lx] stop tracking all
vram\n",
> +                     range->begin_pfn, range->end_pfn);
> +#endif
> +            xfree(range->pl_tab);
> +            xfree(range);
> +        }
> +        /* Free all the extension pages */
> +        
> +        ext = remap_maddr(NULL, dirty_vram->ext_head);
> +        while ( ext ) {
> +            struct page_info *pg = virt_to_page(ext);
> +            ext = remap_maddr(ext, ext->ext_link);
> +            d->arch.paging.free_page(d, pg);
> +        }
> +
> +        xfree(dirty_vram);
> +        d->arch.hvm_domain.dirty_vram = NULL;
> +    }
> +}
> +
> +/* Returns dirty vram range containing gfn, NULL if none */
> +struct dv_range *
> +dirty_vram_range_find_gfn(struct domain *d,
> +                          unsigned long gfn)
> +{
> +    struct dv_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    if ( dirty_vram )
> +    {
> +        struct list_head *curr;
> +        list_for_each(curr, &dirty_vram->range_head)
> +        {
> +            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
> +            if ( gfn >= range->begin_pfn &&
> +                 gfn <  range->end_pfn )
> +                return range;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +/*
> + * Returns pointer to dirty vram range matching [begin_pfn .. end_pfn ),
> + * NULL if none.
> + */
> +dv_range_t *
> +dirty_vram_range_find(struct domain *d,
> +                      unsigned long begin_pfn,
> +                      unsigned long nr)
> +{
> +    unsigned long end_pfn = begin_pfn + nr;
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    if ( dirty_vram )
> +    {
> +        struct list_head *curr;
> +        list_for_each(curr, &dirty_vram->range_head)
> +        {
> +            dv_range_t *range = list_entry(curr, dv_range_t, range_link);
> +            if ( begin_pfn == range->begin_pfn &&
> +                 end_pfn   == range->end_pfn )
> +                return range;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +/* Allocate specified dirty_vram range */
> +static dv_range_t *
> +_dirty_vram_range_alloc(struct domain *d,
> +                        unsigned long begin_pfn,
> +                        unsigned long nr)
> +{
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    dv_range_t *range = NULL;
> +    unsigned long end_pfn = begin_pfn + nr;
> +    dv_pl_entry_t *pl_tab = NULL;
> +    int i;
> +
> +    ASSERT( paging_locked_by_me(d) );
> +    ASSERT( dirty_vram != NULL );
> +
> +#if DEBUG_allocating_dirty_vram_range
> +    gdprintk(XENLOG_DEBUG,
> +             "[%05lx:%05lx] Allocating dirty vram range
hap:%d\n",
> +             begin_pfn, end_pfn,
> +             d->arch.hvm_domain.hap_enabled);
> +#endif
> +
> +    range = xzalloc(dv_range_t);
> +    if ( range == NULL )
> +        goto err_out;
> +
> +    INIT_LIST_HEAD(&range->range_link);
> +
> +    range->begin_pfn = begin_pfn;
> +    range->end_pfn = end_pfn;
> +
> +    if ( !hap_enabled(d) )
> +    {
> +        if ( (pl_tab = xzalloc_array(dv_pl_entry_t, nr)) == NULL )
> +            goto err_out;
> +
> +        for ( i = 0; i != nr; i++ )
> +        {
> +            pl_tab[i].mapping.sl1ma = INVALID_PADDR;
> +            pl_tab[i].mapping.pl_next = INVALID_PADDR;
> +        }
> +    }
> +
> +    range->pl_tab = pl_tab;
> +    range->mappings_hwm = 1;
> +
> +    list_add(&range->range_link, &dirty_vram->range_head);
> +    if ( ++dirty_vram->nr_ranges > dirty_vram->ranges_hwm )
> +    {
> +        dirty_vram->ranges_hwm = dirty_vram->nr_ranges;
> +#if DEBUG_high_water_mark_for_vram_ranges
> +        gdprintk(XENLOG_DEBUG,
> +                 "High water mark for number of vram ranges is
now:%d\n",
> +                 dirty_vram->ranges_hwm);
> +#endif
> +    }
> +    return range;
> +
> + err_out:
> +    xfree(pl_tab);
> +    xfree(range);
> +    return NULL;
> +}
> +
> +/* Frees specified dirty_vram range */
> +void dirty_vram_range_free(struct domain *d,
> +                           dv_range_t *range)
> +{
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    ASSERT( paging_locked_by_me(d) );
> +    if ( dirty_vram )
> +    {
> +        int i, nr = range->end_pfn - range->begin_pfn;
> +
> +#if DEBUG_freeing_dirty_vram_range
> +        gdprintk(XENLOG_DEBUG,
> +                 "[%05lx:%05lx] Freeing dirty vram range\n",
> +                 range->begin_pfn, range->end_pfn);
> +#endif
> +
> +        if ( range->pl_tab )
> +        {
> +            for ( i = 0; i != nr; i++ )
> +            {
> +                dv_paddr_link_t *plx;
> +                
> +                plx = remap_maddr(NULL,
range->pl_tab[i].mapping.pl_next);
> +
> +                /* Does current FB page have multiple mappings? */
> +                if ( plx ) /* Yes */
> +                {
> +                    /* Find the last element in singly-linked list */
> +                    while ( plx->pl_next != INVALID_PADDR ) {
> +                        plx = remap_maddr(plx, plx->pl_next);
> +                    }
> +                    
> +                    /* Prepend whole list to the free list */
> +                    plx->pl_next = dirty_vram->pl_free;
> +                    dirty_vram->pl_free =
range->pl_tab[i].mapping.pl_next;
> +                }
> +                /* Unmap plx. */
> +                remap_vaddr(plx, NULL);
> +            }
> +            xfree(range->pl_tab);
> +            range->pl_tab = NULL;
> +        }
> +        /* Remove range from the linked list, free it, and adjust count*/
> +        list_del(&range->range_link);
> +        xfree(range);
> +        dirty_vram->nr_ranges--;
> +    }
> +}
> +
> +/*
> + * dirty_vram_range_alloc()
> + * This function ensures that the new range does not overlap any existing
> + * ranges -- deleting them if necessary -- and then calls
> + * _dirty_vram_range_alloc to actually allocate the new range.
> + */
> +dv_range_t *
> +dirty_vram_range_alloc(struct domain *d,
> +                        unsigned long begin_pfn,
> +                        unsigned long nr)
> +{
> +    unsigned long end_pfn = begin_pfn + nr;
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    dv_range_t *range;
> +    struct list_head *curr, *next;
> +
> +    ASSERT( paging_locked_by_me(d) );
> +    ASSERT( dirty_vram != NULL );
> +
> +    /*
> +     * Ranges cannot overlap so
> +     * free any range that overlaps [ begin_pfn .. end_pfn ).
> +     */
> +    list_for_each_safe(curr, next, &dirty_vram->range_head)
> +    {
> +        dv_range_t *rng = list_entry(curr, dv_range_t, range_link);
> +        if ( ( ( rng->begin_pfn <= begin_pfn ) &&
> +               ( begin_pfn <  rng->end_pfn   )
> +                 ) ||
> +             ( ( begin_pfn <= rng->begin_pfn ) &&
> +               ( rng->begin_pfn < end_pfn    )
> +                 ) )
> +        {
> +            /* Different tracking, tear the previous down. */
> +            dirty_vram_range_free(d, rng);
> +        }
> +    }
> +
> +    range = _dirty_vram_range_alloc(d, begin_pfn, nr);
> +    if ( !range )
> +        goto out;
> +
> + out:
> +    return range;
> +}
> +
> +/*
> + * dirty_vram_range_find_or_alloc()
> + * Find the range for [begin_pfn:begin_pfn+nr).
> + * If it doesn''t exists, create it.
> + */
> +dv_range_t *
> +dirty_vram_range_find_or_alloc(struct domain *d,
> +                                unsigned long begin_pfn,
> +                                unsigned long nr)
> +{
> +    dv_range_t *range;
> +    ASSERT( paging_locked_by_me(d) );
> +    range = dirty_vram_range_find(d, begin_pfn, nr);
> +    if ( !range )
> +        range = dirty_vram_range_alloc(d, begin_pfn, nr);
> +    
> +    return range;
> +}
> +
> +
> +static paddr_t
> +domain_page_map_to_maddr(void *va)
> +{
> +    if ( va )
> +        return (domain_page_map_to_mfn(va) << PAGE_SHIFT) +
> +            (((unsigned long)va) & ~PAGE_MASK);
> +    else
> +        return INVALID_PADDR;
> +}
> +
> +void *
> +remap_maddr(void *old_va, paddr_t new_ma)
> +{
> +    if ( old_va )
> +        unmap_domain_page(old_va);
> +    
> +    if ( new_ma != INVALID_PADDR )
> +        return map_domain_page(new_ma >> PAGE_SHIFT) + (new_ma &
~PAGE_MASK);
> +    else
> +        return NULL;
> +}
> +
> +void *
> +remap_vaddr(void *old_va, void *new_va)
> +{
> +    if ( old_va )
> +        unmap_domain_page(old_va);
> +    
> +    if ( new_va )
> +        /* Map page now in anticipation of future matching unmap */
> +        map_domain_page(domain_page_map_to_mfn(new_va));
> +
> +    return new_va;
> +}
> +
> +
> +/* Allocate a dv_paddr_link struct */
> +static dv_paddr_link_t *
> +alloc_paddr_link(struct domain *d)
> +{
> +    dv_paddr_link_t *pl = NULL;
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    dv_paddr_link_ext_t *ext = NULL;
> +    
> +
> +    ASSERT( paging_locked_by_me(d) );
> +    BUILD_BUG_ON(sizeof(dv_paddr_link_ext_t) > PAGE_SIZE);
> +    /* Is the list of free pl''s empty? */
> +    if ( dirty_vram->pl_free == INVALID_PADDR ) /* Yes. */
> +    {
> +        /*
> +         * Allocate another page of pl''s.
> +         * Link them all together and point the free list head at them
> +         */
> +        int i;
> +        struct page_info *pg = d->arch.paging.alloc_page(d);
> +        if ( pg == NULL )
> +            goto out;
> +
> +        ext = __map_domain_page(pg);
> +        if ( ext == NULL )
> +        {
> +            d->arch.paging.free_page(d, pg);
> +            goto out;
> +        }
> +
> +#if DEBUG_allocate_paddr_links_page
> +        gdprintk(XENLOG_DEBUG, "Allocated another page of
paddr_links\n");
> +#endif
> +        /* Prepend new extension page to dirty_vram''s list of
same. */
> +        ext->ext_link = dirty_vram->ext_head;
> +        dirty_vram->ext_head = domain_page_map_to_maddr(ext);
> +
> +        /* Initialize and link together the new pl entries. */
> +        for ( i = 0; i != ARRAY_SIZE(ext->entries); i++ )
> +        {
> +            ext->entries[i].sl1ma = INVALID_PADDR;
> +            ext->entries[i].pl_next > +               
domain_page_map_to_maddr(&ext->entries[i+1]);
> +        }
> +        /* Mark the last entry''s next pointer as
"null". */
> +        ext->entries[ARRAY_SIZE(ext->entries) - 1].pl_next =
INVALID_PADDR;
> +
> +        /* Set the dirty_vram''s free list pointer to the first
entry. */
> +        dirty_vram->pl_free =
domain_page_map_to_maddr(&ext->entries[0]);
> +    }
> +    pl = remap_maddr(NULL, dirty_vram->pl_free);
> +    dirty_vram->pl_free = pl->pl_next;
> +
> +    pl->sl1ma = INVALID_PADDR;
> +    pl->pl_next = INVALID_PADDR;
> + out:
> +    if ( ext )
> +        unmap_domain_page(ext);
> +    return pl;
> +}
> +
> +
> +/*
> + * Free a paddr_link struct.
> + *
> + * The caller has walked the singly-linked list of elements
> + * that have, as their head, an element in a pl_tab cell.
> + * The list walk has reached the element to be freed.
> + * (Each element is a dv_paddr_link_t struct.)
> + *
> + * @pl points to the element to be freed.
> + * @ppl points to its predecessor''s next member.
> + *
> + * After linking the predecessor to the element''s successor,
> + * we can free @pl by prepending it to the list of free
> + * elements.
> + *
> + * As a boundary case (which happens to be the common case),
> + * @pl points to a cell in the pl_tab rather than to some
> + * extension element danging from that cell.
> + * We recognize this case because @ppl is NULL.
> + * In that case we promote the first extension element by
> + * copying it into the pl_tab cell and freeing it.
> + *
> + * Returns a pointer to @pl''s successor.  This is where
> + * any iterative processing will resume.
> + */
> +
> +dv_paddr_link_t *
> +free_paddr_link(struct domain *d,
> +                paddr_t *ppl,
> +                dv_paddr_link_t *pl)
> +{
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    dv_paddr_link_t *npl; /* Next pl. */
> +
> +    ASSERT( paging_locked_by_me(d) );
> +    /* Extension mapping? */
> +    if ( ppl ) /* Yes, relink around it. */
> +    {
> +        /* When done, resume processing at pl''s successor. */
> +        npl = remap_maddr(NULL, pl->pl_next);
> +        (*ppl) = domain_page_map_to_maddr(npl);
> +    }
> +    else  /* pl points to entry in the main table. */
> +    {
> +        /*
> +         * Move 2nd mapping to main table
> +         * and free 2nd mapping.
> +         */
> +        dv_paddr_link_t *spl; /* 2nd mapping */
> +        spl = remap_maddr(NULL, pl->pl_next);
> +        /* Is there a 2nd mapping? */
> +        if ( spl == NULL ) /* No. */
> +        {
> +            /* Invalidate the main table entry. */
> +            pl->sl1ma = INVALID_PADDR;
> +            return pl;
> +        }
> +        /* Copy 2nd mapping into main table. */
> +        pl->sl1ma = spl->sl1ma;
> +        pl->pl_next = spl->pl_next;
> +        npl = pl; /* Reprocess main table entry again. */
> +        pl = spl; /* Prepare to free 2nd mapping. */
> +    }
> +
> +    /* Prepare entry for prepending to the free list */
> +    pl->sl1ma = INVALID_PADDR;
> +    pl->pl_next = dirty_vram->pl_free;
> +    dirty_vram->pl_free = domain_page_map_to_maddr(pl);
> +    remap_vaddr(pl, NULL); /* Unmap pl. */
> +
> +    return npl;
> +}
> +
> +
> +/*
> + * dirty_vram_range_update()
> + *
> + * This is called whenever a level 1 page table entry is modified.
> + * If the L1PTE is being cleared, the function removes any paddr_links
> + * that refer to it.
> + * If the L1PTE is being set to a frame buffer page, a paddr_link is
> + * created for that page''s entry in pl_tab.
> + * Returns 1 iff entry found and set or cleared.
> + */
> +int dirty_vram_range_update(struct domain *d,
> +                            unsigned long gfn,
> +                            paddr_t sl1ma,
> +                            int set)
> +{
> +    int effective = 0;
> +    dv_range_t *range;
> +    unsigned long i;
> +    dv_paddr_link_t *pl;
> +    paddr_t *ppl;
> +    int len = 0;
> +
> +    ASSERT(paging_locked_by_me(d));
> +    range = dirty_vram_range_find_gfn(d, gfn);
> +    if ( !range )
> +        return effective;
> +
> +    
> +    i = gfn - range->begin_pfn;
> +    pl = remap_vaddr(NULL, &range->pl_tab[ i ].mapping);
> +    ppl = NULL;
> +    /*
> +     * Find matching entry (pl), if any, and its predecessor (ppl)
> +     * in linked list.
> +     */
> +    while ( pl != NULL )
> +    {
> +        if ( pl->sl1ma == sl1ma || pl->sl1ma == INVALID_PADDR )
> +            break;
> +
> +        ppl = remap_vaddr(ppl, &pl->pl_next);
> +        pl =  remap_maddr(pl, (*ppl));
> +        len++;
> +    }
> +    
> +    if ( set )
> +    {
> +        /* Did we find sl1ma in either the main table or the linked list?
*/
> +        if ( pl == NULL ) /* No, so we''ll need to alloc a link.
*/
> +        {
> +            ASSERT(ppl != NULL); /* ppl points to predecessor''s
next link. */
> +            
> +#if DEBUG_alloc_paddr_inject_fault
> +            {
> +                static int counter;
> +                
> +                /* Test stuck_dirty logic for some cases */
> +                if ( (++counter) % 4 == 0 )
> +                {
> +                    /* Simply mark the frame buffer page as always dirty
*/
> +                    range->pl_tab[ i ].stuck_dirty = 1;
> +                    gdprintk(XENLOG_DEBUG,
> +                             "[%lx] inject stuck dirty fault\n",
> +                             gfn );
> +                    goto out;
> +                }
> +            }
> +#endif
> +            /*
> +             * Have we reached the limit of mappings we''re
willing
> +             * to bookkeep?
> +             */
> +            if ( len > DV_ADDR_LINK_LIST_LIMIT ) /* Yes. */
> +            {
> +#if DEBUG_link_limit_exceeded
> +                if ( !range->pl_tab[ i ].stuck_dirty )
> +                    gdprintk(XENLOG_DEBUG,
> +                             "[%lx] link limit exceeded\n",
> +                             gfn );
> +#endif            
> +                /* Simply mark the frame buffer page as always dirty */
> +                range->pl_tab[ i ].stuck_dirty = 1;
> +                goto out;
> +            }
> +
> +            /* Alloc new link */
> +            pl = alloc_paddr_link(d);
> +            /* Were we able to allocate a link? */
> +            if ( pl == NULL ) /* No. */
> +            {
> +                /* Simply mark the frame buffer page as always dirty */
> +                range->pl_tab[ i ].stuck_dirty = 1;
> +                
> +                gdprintk(XENLOG_DEBUG,
> +                         "[%lx] alloc failure\n",
> +                         gfn );
> +                
> +                goto out;
> +            }
> +            /* Append new link to the list */
> +            (*ppl) = domain_page_map_to_maddr(pl);
> +        }
> +
> +        /* Did we find an entry for sl1ma? */
> +        if ( pl->sl1ma != sl1ma ) /* No. */
> +        {
> +            /* pl must point to either a previously unused entry in the
> +             * main table, or to a newly allocated link.
> +             * In either case, the link''s sl1ma should be
''null''.
> +             */
> +            ASSERT(pl->sl1ma == INVALID_PADDR);
> +            pl->sl1ma = sl1ma;
> +        }
> +        effective = 1; /* Take note that we''re going to set an
entry. */
> +        if ( len > range->mappings_hwm )
> +        {
> +            /* Bookkeep the high water mark. */
> +            range->mappings_hwm = len;
> +#if DEBUG_update_vram_mapping
> +            gdprintk(XENLOG_DEBUG,
> +                     "[%lx] set      sl1ma:%lx hwm:%d "
> +                     "free_pages:%d\n",
> +                     gfn, sl1ma,
> +                     range->mappings_hwm,
> +                     d->arch.paging.shadow.free_pages);
> +#endif
> +        }
> +    }
> +    else /* Clear */
> +    {
> +        if ( pl && pl->sl1ma == sl1ma )
> +        {
> +#if DEBUG_update_vram_mapping
> +            gdprintk(XENLOG_DEBUG,
> +                     "[%lx] clear    sl1ma:%lx\n",
> +                     gfn, sl1ma);
> +#endif
> +            pl = free_paddr_link(d, ppl, pl);
> +            effective = 1; /* Take note that we''re clearing an
entry. */
> +        }
> +    }
> + out:
> +    remap_vaddr(pl,  NULL);
> +    remap_vaddr(ppl, NULL);
> +    return effective;
> +}
> +
> +
> +/*
> + * shadow_scan_dirty_flags()
> + * This produces a dirty bitmap for the range by examining every
> + * L1PTE referenced by some dv_paddr_link in the range''s pl_tab
table.
> + * It tests and clears each such L1PTE''s dirty flag.
> + */
> +static int 
> +shadow_scan_dirty_flags(struct domain *d,
> +                        dv_range_t *range,
> +                        uint8_t *dirty_bitmap)
> +{
> +    int flush_tlb = 0;
> +    unsigned long i;
> +    unsigned long nr = range->end_pfn - range->begin_pfn;
> +    l1_pgentry_t *sl1e = NULL;
> +
> +    ASSERT( paging_locked_by_me(d) );
> +    /* Iterate over VRAM to track dirty bits. */
> +    for ( i = 0; i < nr; i++ )
> +    {
> +        int dirty = 0;
> +        
> +        /* Does the frame buffer have an incomplete set of mappings? */
> +        if ( unlikely(range->pl_tab[i].stuck_dirty) ) /* Yes. */
> +            dirty = 1; /* Then always assume the page is dirty. */
> +        else { /* The frame buffer''s set of mappings is complete.
Scan it. */
> +            paddr_t next = range->pl_tab[i].mapping.pl_next;
> +            paddr_t sl1ma = range->pl_tab[i].mapping.sl1ma;
> +            dv_paddr_link_t *pl = NULL;
> +            for (;;)
> +            {
> +                if ( sl1ma == INVALID_PADDR )
> +                    /* End of list or frame buffer page is unmapped. */
> +                    break;
> +
> +                if ( sl1e ) /* Cleanup from previous iteration. */
> +                    unmap_domain_page(sl1e);
> +
> +                sl1e = map_domain_page(sl1ma >> PAGE_SHIFT) +
> +                    (sl1ma & ~PAGE_MASK);
> +                if ( l1e_get_flags(*sl1e) & _PAGE_DIRTY )
> +                {
> +                    dirty = 1;
> +                    /* Clear dirty so we can detect if page gets
re-dirtied.
> +                     * Note: this is atomic, so we may clear a
> +                     * _PAGE_ACCESSED set by another processor.
> +                     */
> +                    l1e_remove_flags(*sl1e, _PAGE_DIRTY);
> +                    flush_tlb = 1;
> +                    /* Even though we now know the frame buffer page is
dirty,
> +                     * keep iterating to clear the dirty flag in all other
> +                     * mappings. 
> +                     */
> +                }
> +                
> +                pl = remap_maddr(pl, next);
> +                if ( !pl )
> +                    break;
> +                
> +                next = pl->pl_next;
> +                sl1ma = pl->sl1ma;
> +            } /* for */
> +
> +            /* Unmap pl. */
> +            remap_vaddr(NULL, pl);
> +        }
> +        if ( dirty )
> +            /* Set the i''th bit in the output dirty_bitmap */
> +            dirty_bitmap[i >> 3] |= (1 << (i & 7));
> +
> +    }
> +    
> +    if ( sl1e )
> +        unmap_domain_page(sl1e);
> +
> +    return flush_tlb;
> +}
> +
> +
> +/*
> + * shadow_track_dirty_vram()
> + * This is the API called by the guest to determine which pages in the
range
> + * from [begin_pfn:begin_pfn+nr) have been dirtied since the last call.
> + * It creates the domain''s dv_dirty_vram on demand.
> + * It creates ranges on demand when some [begin_pfn:nr) is first
encountered.
> + * To collect the dirty bitmask it calls shadow_scan_dirty_flags().
> + * It copies the dirty bitmask into guest storage.
> + */
> +int shadow_track_dirty_vram(struct domain *d,
> +                            unsigned long begin_pfn,
> +                            unsigned long nr,
> +                            XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
> +{
> +    int rc = 0;
> +    unsigned long end_pfn = begin_pfn + nr;
> +    int flush_tlb = 0;
> +    dv_range_t *range;
> +    struct p2m_domain *p2m = p2m_get_hostp2m(d);
> +    uint8_t *dirty_bitmap = NULL;
> +
> +    /*
> +     * This range test is tricky.
> +     *
> +     * The range [begin_pfn..end_pfn) is an open interval, so end_pfn
> +     * is a pfn beyond the end of the range.
> +     *
> +     * p2m->max_mapped_pfn is a valid PFN so p2m->max_mapped_pfn + 1
is an
> +     * invalid PFN.
> +     *
> +     * If end_pfn is beyond *that* then the range is invalid.
> +     */
> +    if ( end_pfn < begin_pfn
> +         || begin_pfn > p2m->max_mapped_pfn
> +         || end_pfn > p2m->max_mapped_pfn + 1 )
> +        return -EINVAL;
> +
> +    paging_lock(d);
> +
> +    if ( !nr )
> +    {
> +        dirty_vram_free(d);
> +        goto out;
> +    }
> +
> +    if ( guest_handle_is_null(guest_dirty_bitmap) )
> +        goto out;
> +
> +    if ( !dirty_vram_find_or_alloc(d) )
> +    {
> +        rc = -ENOMEM;
> +        goto out;
> +    }
> +
> +    range = dirty_vram_range_find(d, begin_pfn, nr);
> +    if ( !range )
> +    {
> +        range = dirty_vram_range_alloc(d, begin_pfn, nr);
> +        if ( range )
> +            sh_find_all_vram_mappings(d->vcpu[0], range);
> +    }
> +    if ( range )
> +    {
> +        int size = ( nr + BITS_PER_BYTE - 1 ) / BITS_PER_BYTE;
> +        
> +        rc = -ENOMEM;
> +        dirty_bitmap = xzalloc_bytes( size );
> +        if ( !dirty_bitmap )
> +            goto out;
> +
> +        flush_tlb |= shadow_scan_dirty_flags(d, range, dirty_bitmap);
> +
> +        rc = -EFAULT;
> +        if ( copy_to_guest(guest_dirty_bitmap,
> +                           dirty_bitmap,
> +                           size) == 0 )
> +            rc = 0;
> +    }
> +    
> +    if ( flush_tlb )
> +        flush_tlb_mask(d->domain_dirty_cpumask);
> +
> +out:
> +    paging_unlock(d);
> +    
> +    if ( dirty_bitmap )
> +        xfree(dirty_bitmap);
> +    return rc;
> +}
> +
> +
> +/************************************************/
> +/*          HAP VRAM TRACKING SUPPORT           */
> +/************************************************/
> +
> +/*
> + * hap_track_dirty_vram()
> + * Create the domain''s dv_dirty_vram struct on demand.
> + * Create a dirty vram range on demand when some [begin_pfn:begin_pfn+nr]
is
> + * first encountered.
> + * Collect the guest_dirty bitmask, a bit mask of the dirty vram pages, by
> + * calling paging_log_dirty_range(), which interrogates each vram
> + * page''s p2m type looking for pages that have been made
writable.
> + */
> +int hap_track_dirty_vram(struct domain *d,
> +                         unsigned long begin_pfn,
> +                         unsigned long nr,
> +                         XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
> +{
> +    long rc = 0;
> +    dv_dirty_vram_t *dirty_vram;
> +    uint8_t *dirty_bitmap = NULL;
> +
> +    if ( nr )
> +    {
> +        dv_range_t *range = NULL;
> +        int size = ( nr + BITS_PER_BYTE - 1 ) / BITS_PER_BYTE;
> +        
> +        if ( !paging_mode_log_dirty(d) )
> +        {
> +            hap_logdirty_init(d);
> +            rc = paging_log_dirty_enable(d);
> +            if ( rc )
> +                goto out;
> +        }
> +
> +        rc = -ENOMEM;
> +        dirty_bitmap = xzalloc_bytes( size );
> +        if ( !dirty_bitmap )
> +            goto out;
> +        
> +        paging_lock(d);
> +        
> +        dirty_vram = d->arch.hvm_domain.dirty_vram;
> +        if ( !dirty_vram ) 
> +        {
> +            rc = -ENOMEM;
> +            if ( !(dirty_vram = dirty_vram_alloc(d)) )
> +            {
> +                paging_unlock(d);
> +                goto out;
> +            }
> +        }
> +        
> +        range = dirty_vram_range_find(d, begin_pfn, nr);
> +        if ( !range )
> +        {
> +            rc = -ENOMEM;
> +            if ( !(range = dirty_vram_range_alloc(d, begin_pfn, nr)) )
> +            {
> +                paging_unlock(d);
> +                goto out;
> +            }
> +            
> +            paging_unlock(d);
> +            
> +            /* Set l1e entries of range within P2M table to be read-only.
*/
> +            p2m_change_type_range(d, begin_pfn, begin_pfn + nr,
> +                                  p2m_ram_rw, p2m_ram_logdirty);
> +            
> +            flush_tlb_mask(d->domain_dirty_cpumask);
> +            
> +            memset(dirty_bitmap, 0xff, size); /* Consider all pages dirty.
*/
> +        }
> +        else
> +        {
> +            paging_unlock(d);
> +            
> +            domain_pause(d);
> +            
> +            /* Get the bitmap. */
> +            paging_log_dirty_range(d, begin_pfn, nr, dirty_bitmap);
> +            
> +            domain_unpause(d);
> +        }
> +        
> +        
> +        rc = -EFAULT;
> +        if ( copy_to_guest(guest_dirty_bitmap,
> +                           dirty_bitmap,
> +                           size) == 0 )
> +        {
> +            rc = 0;
> +        }
> +    }
> +    else {
> +        paging_lock(d);
> +        
> +        dirty_vram = d->arch.hvm_domain.dirty_vram;
> +        if ( dirty_vram )
> +        {
> +            /*
> +             * If zero pages specified while tracking dirty vram
> +             * then stop tracking
> +             */
> +            dirty_vram_free(d);
> +        
> +        }
> +        
> +        paging_unlock(d);
> +    }
> +out:
> +    if ( dirty_bitmap )
> +        xfree(dirty_bitmap);
> +    
> +    return rc;
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
> index f353d3a..3ac54c9 100644
> --- a/xen/arch/x86/mm/hap/hap.c
> +++ b/xen/arch/x86/mm/hap/hap.c
> @@ -53,117 +53,6 @@
>  #define page_to_mfn(_pg) _mfn(__page_to_mfn(_pg))
>  
>  /************************************************/
> -/*          HAP VRAM TRACKING SUPPORT           */
> -/************************************************/
> -
> -/*
> - * hap_track_dirty_vram()
> - * Create the domain''s dv_dirty_vram struct on demand.
> - * Create a dirty vram range on demand when some [begin_pfn:begin_pfn+nr]
is
> - * first encountered.
> - * Collect the guest_dirty bitmask, a bit mask of the dirty vram pages, by
> - * calling paging_log_dirty_range(), which interrogates each vram
> - * page''s p2m type looking for pages that have been made
writable.
> - */
> -
> -int hap_track_dirty_vram(struct domain *d,
> -                         unsigned long begin_pfn,
> -                         unsigned long nr,
> -                         XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
> -{
> -    long rc = 0;
> -    struct sh_dirty_vram *dirty_vram;
> -    uint8_t *dirty_bitmap = NULL;
> -
> -    if ( nr )
> -    {
> -        int size = (nr + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
> -
> -        if ( !paging_mode_log_dirty(d) )
> -        {
> -            hap_logdirty_init(d);
> -            rc = paging_log_dirty_enable(d);
> -            if ( rc )
> -                goto out;
> -        }
> -
> -        rc = -ENOMEM;
> -        dirty_bitmap = xzalloc_bytes(size);
> -        if ( !dirty_bitmap )
> -            goto out;
> -
> -        paging_lock(d);
> -
> -        dirty_vram = d->arch.hvm_domain.dirty_vram;
> -        if ( !dirty_vram )
> -        {
> -            rc = -ENOMEM;
> -            if ( (dirty_vram = xzalloc(struct sh_dirty_vram)) == NULL )
> -            {
> -                paging_unlock(d);
> -                goto out;
> -            }
> -
> -            d->arch.hvm_domain.dirty_vram = dirty_vram;
> -        }
> -
> -        if ( begin_pfn != dirty_vram->begin_pfn ||
> -             begin_pfn + nr != dirty_vram->end_pfn )
> -        {
> -            dirty_vram->begin_pfn = begin_pfn;
> -            dirty_vram->end_pfn = begin_pfn + nr;
> -
> -            paging_unlock(d);
> -
> -            /* set l1e entries of range within P2M table to be read-only.
*/
> -            p2m_change_type_range(d, begin_pfn, begin_pfn + nr,
> -                                  p2m_ram_rw, p2m_ram_logdirty);
> -
> -            flush_tlb_mask(d->domain_dirty_cpumask);
> -
> -            memset(dirty_bitmap, 0xff, size); /* consider all pages dirty
*/
> -        }
> -        else
> -        {
> -            paging_unlock(d);
> -
> -            domain_pause(d);
> -
> -            /* get the bitmap */
> -            paging_log_dirty_range(d, begin_pfn, nr, dirty_bitmap);
> -
> -            domain_unpause(d);
> -        }
> -
> -        rc = -EFAULT;
> -        if ( copy_to_guest(guest_dirty_bitmap, dirty_bitmap, size) == 0 )
> -            rc = 0;
> -    }
> -    else
> -    {
> -        paging_lock(d);
> -
> -        dirty_vram = d->arch.hvm_domain.dirty_vram;
> -        if ( dirty_vram )
> -        {
> -            /*
> -             * If zero pages specified while tracking dirty vram
> -             * then stop tracking
> -             */
> -            xfree(dirty_vram);
> -            d->arch.hvm_domain.dirty_vram = NULL;
> -        }
> -
> -        paging_unlock(d);
> -    }
> -out:
> -    if ( dirty_bitmap )
> -        xfree(dirty_bitmap);
> -
> -    return rc;
> -}
> -
> -/************************************************/
>  /*            HAP LOG DIRTY SUPPORT             */
>  /************************************************/
>  
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index de1dd82..6f638a2 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -741,20 +741,23 @@ void p2m_change_type_range(struct domain *d,
>      struct p2m_domain *p2m = p2m_get_hostp2m(d);
>  
>      BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
> -
>      p2m_lock(p2m);
> -    p2m->defer_nested_flush = 1;
>  
> +    p2m->defer_nested_flush = 1;
> +    
>      for ( gfn = start; gfn < end; gfn++ )
>      {
>          mfn = p2m->get_entry(p2m, gfn, &pt, &a, 0, NULL);
>          if ( pt == ot )
> -            set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, nt,
p2m->default_access);
> +            set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, nt,
> +                          p2m->default_access);
>      }
> -
> +    
>      p2m->defer_nested_flush = 0;
> +
>      if ( nestedhvm_enabled(d) )
>          p2m_flush_nestedp2m(d);
> +
>      p2m_unlock(p2m);
>  }
>  
> diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
> index ac9bb1a..d59e8d6 100644
> --- a/xen/arch/x86/mm/paging.c
> +++ b/xen/arch/x86/mm/paging.c
> @@ -27,6 +27,7 @@
>  #include <asm/p2m.h>
>  #include <asm/hap.h>
>  #include <asm/hvm/nestedhvm.h>
> +#include <asm/dirty_vram.h>
>  #include <xen/numa.h>
>  #include <xsm/xsm.h>
>  
> @@ -192,15 +193,11 @@ int paging_log_dirty_disable(struct domain *d)
>      return ret;
>  }
>  
> -/* Mark a page as dirty */
> +/* Given a guest mfn, mark a page as dirty */
>  void paging_mark_dirty(struct domain *d, unsigned long guest_mfn)
>  {
>      unsigned long pfn;
>      mfn_t gmfn;
> -    int changed;
> -    mfn_t mfn, *l4, *l3, *l2;
> -    unsigned long *l1;
> -    int i1, i2, i3, i4;
>  
>      gmfn = _mfn(guest_mfn);
>  
> @@ -210,6 +207,19 @@ void paging_mark_dirty(struct domain *d, unsigned long
guest_mfn)
>  
>      /* We /really/ mean PFN here, even for non-translated guests. */
>      pfn = get_gpfn_from_mfn(mfn_x(gmfn));
> +    paging_mark_dirty_gpfn(d, pfn);
> +}
> +
> +
> +/* Given a guest pfn, mark a page as dirty */
> +void paging_mark_dirty_gpfn(struct domain *d, unsigned long pfn)
> +{
> +    int changed;
> +    mfn_t mfn, *l4, *l3, *l2;
> +    unsigned long *l1;
> +    int i1, i2, i3, i4;
> +    dv_range_t *range;
> +    
>      /* Shared MFNs should NEVER be marked dirty */
>      BUG_ON(SHARED_M2P(pfn));
>  
> @@ -229,6 +239,11 @@ void paging_mark_dirty(struct domain *d, unsigned long
guest_mfn)
>      /* Recursive: this is called from inside the shadow code */
>      paging_lock_recursive(d);
>  
> +    d->arch.paging.log_dirty.dirty_count++;
> +    range = dirty_vram_range_find_gfn(d, pfn);
> +    if ( range )
> +        range->dirty_count++;
> +
>      if ( unlikely(!mfn_valid(d->arch.paging.log_dirty.top)) ) 
>      {
>           d->arch.paging.log_dirty.top = paging_new_log_dirty_node(d);
> @@ -445,7 +460,31 @@ void paging_log_dirty_range(struct domain *d,
>      struct p2m_domain *p2m = p2m_get_hostp2m(d);
>      int i;
>      unsigned long pfn;
> +    dv_range_t *range;
> +    unsigned int range_dirty_count;
>  
> +    paging_lock(d);
> +    range = dirty_vram_range_find_gfn(d, begin_pfn);
> +    if ( !range )
> +    {
> +        paging_unlock(d);
> +        goto out;
> +    }
> +    
> +    range_dirty_count = range->dirty_count;
> +    range->dirty_count = 0;
> +
> +    paging_unlock(d);
> +    
> +    if ( !range_dirty_count)
> +        goto out;
> +
> +    PAGING_DEBUG(LOGDIRTY,
> +                 "log-dirty-range: dom %u [%05lx:%05lx]
range_dirty=%u\n",
> +                 d->domain_id,
> +                 begin_pfn,
> +                 begin_pfn + nr,
> +                 range_dirty_count);
>      /*
>       * Set l1e entries of P2M table to be read-only.
>       *
> @@ -460,15 +499,17 @@ void paging_log_dirty_range(struct domain *d,
>  
>      for ( i = 0, pfn = begin_pfn; pfn < begin_pfn + nr; i++, pfn++ )
>      {
> -        p2m_type_t pt;
> -        pt = p2m_change_type(d, pfn, p2m_ram_rw, p2m_ram_logdirty);
> -        if ( pt == p2m_ram_rw )
> +        if ( p2m_change_type(d, pfn, p2m_ram_rw, p2m_ram_logdirty) => +
p2m_ram_rw )
>              dirty_bitmap[i >> 3] |= (1 << (i & 7));
>      }
>  
>      p2m_unlock(p2m);
>  
>      flush_tlb_mask(d->domain_dirty_cpumask);
> +
> + out:
> +    return;
>  }
>  
>  /* Note that this function takes three function pointers. Callers must
supply
> diff --git a/xen/arch/x86/mm/shadow/common.c
b/xen/arch/x86/mm/shadow/common.c
> index 292c1f7..b72a6bb 100644
> --- a/xen/arch/x86/mm/shadow/common.c
> +++ b/xen/arch/x86/mm/shadow/common.c
> @@ -36,6 +36,7 @@
>  #include <asm/current.h>
>  #include <asm/flushtlb.h>
>  #include <asm/shadow.h>
> +#include <asm/dirty_vram.h>
>  #include <xen/numa.h>
>  #include "private.h"
>  
> @@ -3121,12 +3122,7 @@ void shadow_teardown(struct domain *d)
>       * calls now that we''ve torn down the bitmap */
>      d->arch.paging.mode &= ~PG_log_dirty;
>  
> -    if (d->arch.hvm_domain.dirty_vram) {
> -        xfree(d->arch.hvm_domain.dirty_vram->sl1ma);
> -        xfree(d->arch.hvm_domain.dirty_vram->dirty_bitmap);
> -        xfree(d->arch.hvm_domain.dirty_vram);
> -        d->arch.hvm_domain.dirty_vram = NULL;
> -    }
> +    dirty_vram_free(d);
>  
>      paging_unlock(d);
>  
> @@ -3464,194 +3460,219 @@ void shadow_clean_dirty_bitmap(struct domain *d)
>  
> 
/**************************************************************************/
>  /* VRAM dirty tracking support */
> -int shadow_track_dirty_vram(struct domain *d,
> -                            unsigned long begin_pfn,
> -                            unsigned long nr,
> -                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap)
> -{
> -    int rc;
> -    unsigned long end_pfn = begin_pfn + nr;
> -    unsigned long dirty_size = (nr + 7) / 8;
> -    int flush_tlb = 0;
> -    unsigned long i;
> -    p2m_type_t t;
> -    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
> -    struct p2m_domain *p2m = p2m_get_hostp2m(d);
>  
> -    if (end_pfn < begin_pfn
> -            || begin_pfn > p2m->max_mapped_pfn
> -            || end_pfn >= p2m->max_mapped_pfn)
> -        return -EINVAL;
>  
> -    /* We perform p2m lookups, so lock the p2m upfront to avoid deadlock
*/
> -    p2m_lock(p2m_get_hostp2m(d));
> -    paging_lock(d);
> +/* Support functions for shadow-based dirty VRAM code */
>  
> -    if ( dirty_vram && (!nr ||
> -             ( begin_pfn != dirty_vram->begin_pfn
> -            || end_pfn   != dirty_vram->end_pfn )) )
> -    {
> -        /* Different tracking, tear the previous down. */
> -        gdprintk(XENLOG_INFO, "stopping tracking VRAM %lx -
%lx\n", dirty_vram->begin_pfn, dirty_vram->end_pfn);
> -        xfree(dirty_vram->sl1ma);
> -        xfree(dirty_vram->dirty_bitmap);
> -        xfree(dirty_vram);
> -        dirty_vram = d->arch.hvm_domain.dirty_vram = NULL;
> -    }
> +#define DEBUG_unshadow_sl1ma                  0          
> +#define DEBUG_unshadow_sl1ma_detail           0
> +#define DEBUG_count_initial_mappings          0
>  
> -    if ( !nr )
> +/* smfn is no longer a shadow page.  Remove it from any
> + * dirty vram range mapping. */
> +void
> +dirty_vram_delete_shadow(struct vcpu *v,
> +                         unsigned long gfn,
> +                         unsigned int shadow_type, 
> +                         mfn_t smfn)
> +{
> +    static unsigned int l1_shadow_mask = 
> +          1 << SH_type_l1_32_shadow
> +        | 1 << SH_type_fl1_32_shadow
> +        | 1 << SH_type_l1_pae_shadow
> +        | 1 << SH_type_fl1_pae_shadow
> +        | 1 << SH_type_l1_64_shadow
> +        | 1 << SH_type_fl1_64_shadow
> +        ;
> +    struct domain *d = v->domain;
> +    dv_dirty_vram_t *dirty_vram;
> +    struct list_head *curr, *next;
> +    dv_paddr_link_t *pl = NULL;
> +    paddr_t *ppl = NULL;
> +    
> +    ASSERT(paging_locked_by_me(d));
> +    /* Ignore all but level 1 shadows */
> +    
> +    if ( (l1_shadow_mask & (1 << shadow_type)) == 0 )
>      {
> -        rc = 0;
>          goto out;
>      }
>  
> -    /* This should happen seldomly (Video mode change),
> -     * no need to be careful. */
> +    dirty_vram = d->arch.hvm_domain.dirty_vram;
>      if ( !dirty_vram )
>      {
> -        /* Throw away all the shadows rather than walking through them 
> -         * up to nr times getting rid of mappings of each pfn */
> -        shadow_blow_tables(d);
> -
> -        gdprintk(XENLOG_INFO, "tracking VRAM %lx - %lx\n",
begin_pfn, end_pfn);
> -
> -        rc = -ENOMEM;
> -        if ( (dirty_vram = xmalloc(struct sh_dirty_vram)) == NULL )
> -            goto out;
> -        dirty_vram->begin_pfn = begin_pfn;
> -        dirty_vram->end_pfn = end_pfn;
> -        d->arch.hvm_domain.dirty_vram = dirty_vram;
> -
> -        if ( (dirty_vram->sl1ma = xmalloc_array(paddr_t, nr)) == NULL )
> -            goto out_dirty_vram;
> -        memset(dirty_vram->sl1ma, ~0, sizeof(paddr_t) * nr);
> -
> -        if ( (dirty_vram->dirty_bitmap = xzalloc_array(uint8_t,
dirty_size)) == NULL )
> -            goto out_sl1ma;
> -
> -        dirty_vram->last_dirty = NOW();
> -
> -        /* Tell the caller that this time we could not track dirty bits.
*/
> -        rc = -ENODATA;
> -    }
> -    else if (dirty_vram->last_dirty == -1)
> -    {
> -        /* still completely clean, just copy our empty bitmap */
> -        rc = -EFAULT;
> -        if ( copy_to_guest(dirty_bitmap, dirty_vram->dirty_bitmap,
dirty_size) == 0 )
> -            rc = 0;
> +        goto out;
>      }
> -    else
> +        
> +    list_for_each_safe(curr, next, &dirty_vram->range_head)
>      {
> -        unsigned long map_mfn = INVALID_MFN;
> -        void *map_sl1p = NULL;
> -
> -        /* Iterate over VRAM to track dirty bits. */
> -        for ( i = 0; i < nr; i++ ) {
> -            mfn_t mfn = get_gfn_query_unlocked(d, begin_pfn + i, &t);
> -            struct page_info *page;
> -            int dirty = 0;
> -            paddr_t sl1ma = dirty_vram->sl1ma[i];
> +        dv_range_t *range = list_entry(curr, dv_range_t, range_link);
> +        unsigned long i;
> +        int max_mappings = 1, mappings = 0;
> +        int unshadowed = 0;
> +        for ( i = 0; i != range->end_pfn - range->begin_pfn; i++ )
> +        {
> +            
> +            pl = remap_vaddr(pl, &range->pl_tab[ i ].mapping);
> +            /* clean up from previous iteration */
> +            ppl = remap_vaddr(ppl, NULL); /* unmap ppl */
>  
> -            if (mfn_x(mfn) == INVALID_MFN)
> -            {
> -                dirty = 1;
> -            }
> -            else
> +            mappings = 0;
> +            
> +            while ( pl != NULL )
>              {
> -                page = mfn_to_page(mfn);
> -                switch (page->u.inuse.type_info & PGT_count_mask)
> -                {
> -                case 0:
> -                    /* No guest reference, nothing to track. */
> -                    break;
> -                case 1:
> -                    /* One guest reference. */
> -                    if ( sl1ma == INVALID_PADDR )
> -                    {
> -                        /* We don''t know which sl1e points to
this, too bad. */
> -                        dirty = 1;
> -                        /* TODO: Heuristics for finding the single mapping
of
> -                         * this gmfn */
> -                        flush_tlb |= sh_remove_all_mappings(d->vcpu[0],
mfn);
> -                    }
> -                    else
> -                    {
> -                        /* Hopefully the most common case: only one
mapping,
> -                         * whose dirty bit we can use. */
> -                        l1_pgentry_t *sl1e;
> -                        unsigned long sl1mfn = paddr_to_pfn(sl1ma);
> -
> -                        if ( sl1mfn != map_mfn )
> -                        {
> -                            if ( map_sl1p )
> -                                sh_unmap_domain_page(map_sl1p);
> -                            map_sl1p = sh_map_domain_page(_mfn(sl1mfn));
> -                            map_mfn = sl1mfn;
> -                        }
> -                        sl1e = map_sl1p + (sl1ma & ~PAGE_MASK);
> -
> -                        if ( l1e_get_flags(*sl1e) & _PAGE_DIRTY )
> -                        {
> -                            dirty = 1;
> -                            /* Note: this is atomic, so we may clear a
> -                             * _PAGE_ACCESSED set by another processor. */
> -                            l1e_remove_flags(*sl1e, _PAGE_DIRTY);
> -                            flush_tlb = 1;
> -                        }
> -                    }
> -                    break;
> -                default:
> -                    /* More than one guest reference,
> -                     * we don''t afford tracking that. */
> -                    dirty = 1;
> +                paddr_t sl1ma = pl->sl1ma;
> +                unsigned long sl1mn;
> +               
> +                if ( sl1ma == INVALID_PADDR )
>                      break;
> +                
> +                sl1mn = sl1ma >> PAGE_SHIFT;
> +                if ( sl1mn == mfn_x(smfn) ) {
> +#if DEBUG_unshadow_sl1ma_detail
> +                    gdprintk(XENLOG_DEBUG,
> +                             "[%lx] gfn[%lx] unshadow
sl1ma:%lx\n",
> +                             mfn_x(smfn),
> +                             range->begin_pfn + i,
> +                             sl1ma);
> +#endif
> +                    unshadowed++;
> +                    pl = free_paddr_link(d, ppl, pl);
> +                    /* ppl remains unchanged. */
> +                }
> +                else
> +                {
> +                    ppl = remap_vaddr(ppl, &pl->pl_next);
> +                    pl =  remap_maddr(pl, (*ppl));
> +                    mappings++;
>                  }
> -            }
> -
> -            if ( dirty )
> -            {
> -                dirty_vram->dirty_bitmap[i / 8] |= 1 << (i % 8);
> -                dirty_vram->last_dirty = NOW();
>              }
>          }
> +        if ( mappings > max_mappings )
> +            max_mappings = mappings;
> +        
> +        if ( unshadowed ) {
> +#if DEBUG_unshadow_sl1ma
> +            gdprintk(XENLOG_DEBUG,
> +                     "[%lx] gfn[%05lx:%05lx] unshadowed:%d
mappings:0x%x "
> +                     "max_mappings:%d\n",
> +                     mfn_x(smfn),
> +                     range->begin_pfn, range->end_pfn,
> +                     unshadowed, range->nr_mappings, max_mappings);
> +#endif
> +        }
> +    }
> + out:
> +    remap_vaddr(pl,  NULL); /* unmap pl */
> +    remap_vaddr(ppl, NULL); /* unmap ppl */
> +    return;
> +}
> +
>  
> -        if ( map_sl1p )
> -            sh_unmap_domain_page(map_sl1p);
> +typedef int (*hash_pfn_callback_t)(struct vcpu *v,
> +                                   mfn_t smfn,
> +                                   unsigned long begin_pfn,
> +                                   unsigned long end_pfn,
> +                                   int *removed);
>  
> -        rc = -EFAULT;
> -        if ( copy_to_guest(dirty_bitmap, dirty_vram->dirty_bitmap,
dirty_size) == 0 ) {
> -            memset(dirty_vram->dirty_bitmap, 0, dirty_size);
> -            if (dirty_vram->last_dirty + SECONDS(2) < NOW())
> +static int hash_pfn_foreach(struct vcpu *v, 
> +                            unsigned int callback_mask, 
> +                            hash_pfn_callback_t callbacks[], 
> +                            unsigned long begin_pfn,
> +                            unsigned long end_pfn)
> +/* Walk the hash table looking at the types of the entries and 
> + * calling the appropriate callback function for each entry. 
> + * The mask determines which shadow types we call back for, and the array
> + * of callbacks tells us which function to call.
> + * Any callback may return non-zero to let us skip the rest of the scan. 
> + *
> + * WARNING: Callbacks MUST NOT add or remove hash entries unless they 
> + * then return non-zero to terminate the scan. */
> +{
> +    int i, done = 0, removed = 0;
> +    struct domain *d = v->domain;
> +    struct page_info *x;
> +
> +    /* Say we''re here, to stop hash-lookups reordering the chains
*/
> +    ASSERT(paging_locked_by_me(d));
> +    ASSERT(d->arch.paging.shadow.hash_walking == 0);
> +    d->arch.paging.shadow.hash_walking = 1;
> +
> +    for ( i = 0; i < SHADOW_HASH_BUCKETS; i++ ) 
> +    {
> +        /* WARNING: This is not safe against changes to the hash table.
> +         * The callback *must* return non-zero if it has inserted or
> +         * deleted anything from the hash (lookups are OK, though). */
> +        for ( x = d->arch.paging.shadow.hash_table[i];
> +              x;
> +              x = next_shadow(x) )
> +        {
> +            if ( callback_mask & (1 << x->u.sh.type) )
>              {
> -                /* was clean for more than two seconds, try to disable
guest
> -                 * write access */
> -                for ( i = begin_pfn; i < end_pfn; i++ ) {
> -                    mfn_t mfn = get_gfn_query_unlocked(d, i, &t);
> -                    if (mfn_x(mfn) != INVALID_MFN)
> -                        flush_tlb |= sh_remove_write_access(d->vcpu[0],
mfn, 1, 0);
> -                }
> -                dirty_vram->last_dirty = -1;
> +                ASSERT(x->u.sh.type <= 15);
> +                ASSERT(callbacks[x->u.sh.type] != NULL);
> +                done = callbacks[x->u.sh.type](v, page_to_mfn(x), 
> +                                               begin_pfn, end_pfn,
> +                                               &removed);
> +                if ( done ) break;
>              }
> -            rc = 0;
>          }
> +        if ( done ) break; 
>      }
> -    if ( flush_tlb )
> -        flush_tlb_mask(d->domain_dirty_cpumask);
> -    goto out;
> +    d->arch.paging.shadow.hash_walking = 0;
> +    return removed;
> +}
> +
> +void sh_find_all_vram_mappings(struct vcpu *v,
> +                               dv_range_t *range)
> +{
> +    /* Dispatch table for getting per-type functions */
> +    static hash_pfn_callback_t callbacks[SH_type_unused] = {
> +        NULL, /* none    */
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 2), /* l1_32  
*/
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 2), /* fl1_32 
*/
> +        NULL, /* l2_32   */
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 3), /* l1_pae 
*/
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 3), /* fl1_pae
*/
> +        NULL, /* l2_pae  */
> +        NULL, /* l2h_pae */
> +#if CONFIG_PAGING_LEVELS >= 4
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 4), /* l1_64  
*/
> +        SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, 4), /* fl1_64 
*/
> +#else
> +        NULL, /* l1_64   */
> +        NULL, /* fl1_64  */
> +#endif
> +        NULL, /* l2_64   */
> +        NULL, /* l2h_64  */
> +        NULL, /* l3_64   */
> +        NULL, /* l4_64   */
> +        NULL, /* p2m     */
> +        NULL  /* unused  */
> +    };
>  
> -out_sl1ma:
> -    xfree(dirty_vram->sl1ma);
> -out_dirty_vram:
> -    xfree(dirty_vram);
> -    dirty_vram = d->arch.hvm_domain.dirty_vram = NULL;
> +    static unsigned int callback_mask = 
> +          1 << SH_type_l1_32_shadow
> +        | 1 << SH_type_fl1_32_shadow
> +        | 1 << SH_type_l1_pae_shadow
> +        | 1 << SH_type_fl1_pae_shadow
> +        | 1 << SH_type_l1_64_shadow
> +        | 1 << SH_type_fl1_64_shadow
> +        ;
>  
> -out:
> -    paging_unlock(d);
> -    p2m_unlock(p2m_get_hostp2m(d));
> -    return rc;
> +    perfc_incr(shadow_mappings);
> +
> +    hash_pfn_foreach(v, callback_mask, callbacks,
> +                     range->begin_pfn,
> +                     range->end_pfn);
> +
> +#if DEBUG_count_initial_mappings
> +    gdprintk(XENLOG_DEBUG, "[%05lx:%05lx] count of initial\n",
> +             range->begin_pfn, range->end_pfn
> +#endif
>  }
>  
> +
> 
/**************************************************************************/
>  /* Shadow-control XEN_DOMCTL dispatcher */
>  
> diff --git a/xen/arch/x86/mm/shadow/multi.c
b/xen/arch/x86/mm/shadow/multi.c
> index b79cd6c..922e01a 100644
> --- a/xen/arch/x86/mm/shadow/multi.c
> +++ b/xen/arch/x86/mm/shadow/multi.c
> @@ -35,6 +35,7 @@
>  #include <asm/flushtlb.h>
>  #include <asm/hvm/hvm.h>
>  #include <asm/hvm/cacheattr.h>
> +#include <asm/dirty_vram.h>
>  #include <asm/mtrr.h>
>  #include <asm/guest_pt.h>
>  #include <public/sched.h>
> @@ -149,6 +150,10 @@ delete_fl1_shadow_status(struct vcpu *v, gfn_t gfn,
mfn_t smfn)
>      SHADOW_PRINTK("gfn=%"SH_PRI_gfn", type=%08x,
smfn=%05lx\n",
>                     gfn_x(gfn), SH_type_fl1_shadow, mfn_x(smfn));
>      ASSERT(mfn_to_page(smfn)->u.sh.head);
> +
> +    /* Removing any dv_paddr_links to the erstwhile shadow page */
> +    dirty_vram_delete_shadow(v, gfn_x(gfn), SH_type_fl1_shadow, smfn);
> +    
>      shadow_hash_delete(v, gfn_x(gfn), SH_type_fl1_shadow, smfn);
>  }
>  
> @@ -160,6 +165,10 @@ delete_shadow_status(struct vcpu *v, mfn_t gmfn, u32
shadow_type, mfn_t smfn)
>                     v->domain->domain_id, v->vcpu_id,
>                     mfn_x(gmfn), shadow_type, mfn_x(smfn));
>      ASSERT(mfn_to_page(smfn)->u.sh.head);
> +    
> +    /* Removing any dv_paddr_links to the erstwhile shadow page */
> +    dirty_vram_delete_shadow(v, mfn_x(gmfn), shadow_type, smfn);
> +    
>      shadow_hash_delete(v, mfn_x(gmfn), shadow_type, smfn);
>      /* 32-on-64 PV guests don''t own their l4 pages; see
set_shadow_status */
>      if ( !is_pv_32on64_vcpu(v) || shadow_type != SH_type_l4_64_shadow )
> @@ -516,7 +525,6 @@ _sh_propagate(struct vcpu *v,
>      guest_l1e_t guest_entry = { guest_intpte };
>      shadow_l1e_t *sp = shadow_entry_ptr;
>      struct domain *d = v->domain;
> -    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
>      gfn_t target_gfn = guest_l1e_get_gfn(guest_entry);
>      u32 pass_thru_flags;
>      u32 gflags, sflags;
> @@ -663,17 +671,6 @@ _sh_propagate(struct vcpu *v,
>          }
>      }
>  
> -    if ( unlikely((level == 1) && dirty_vram
> -            && dirty_vram->last_dirty == -1
> -            && gfn_x(target_gfn) >= dirty_vram->begin_pfn
> -            && gfn_x(target_gfn) < dirty_vram->end_pfn) )
> -    {
> -        if ( ft & FETCH_TYPE_WRITE )
> -            dirty_vram->last_dirty = NOW();
> -        else
> -            sflags &= ~_PAGE_RW;
> -    }
> -
>      /* Read-only memory */
>      if ( p2m_is_readonly(p2mt) ||
>           (p2mt == p2m_mmio_direct &&
> @@ -1072,101 +1069,60 @@ static int shadow_set_l2e(struct vcpu *v,
>      return flags;
>  }
>  
> -static inline void shadow_vram_get_l1e(shadow_l1e_t new_sl1e,
> +/* shadow_vram_fix_l1e()
> + *
> + * Tests L1PTEs as they are modified, looking for when they start to (or
> + * cease to) point to frame buffer pages.  If the old and new gfns differ,
> + * calls dirty_vram_range_update() to updates the dirty_vram structures.
> + */
> +static inline void shadow_vram_fix_l1e(shadow_l1e_t old_sl1e,
> +                                       shadow_l1e_t new_sl1e,
>                                         shadow_l1e_t *sl1e,
>                                         mfn_t sl1mfn,
>                                         struct domain *d)
>  { 
> -    mfn_t mfn = shadow_l1e_get_mfn(new_sl1e);
> -    int flags = shadow_l1e_get_flags(new_sl1e);
> -    unsigned long gfn;
> -    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
> +    mfn_t new_mfn, old_mfn;
> +    unsigned long new_gfn = INVALID_M2P_ENTRY, old_gfn =
INVALID_M2P_ENTRY;
> +    paddr_t sl1ma;
> +    dv_dirty_vram_t *dirty_vram = d->arch.hvm_domain.dirty_vram;
>  
> -    if ( !dirty_vram         /* tracking disabled? */
> -         || !(flags & _PAGE_RW) /* read-only mapping? */
> -         || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
> +    if ( !dirty_vram )
>          return;
>  
> -    gfn = mfn_to_gfn(d, mfn);
> -    /* Page sharing not supported on shadow PTs */
> -    BUG_ON(SHARED_M2P(gfn));
> +    sl1ma = pfn_to_paddr(mfn_x(sl1mfn)) | ((unsigned long)sl1e &
~PAGE_MASK);
>  
> -    if ( (gfn >= dirty_vram->begin_pfn) && (gfn <
dirty_vram->end_pfn) )
> +    old_mfn = shadow_l1e_get_mfn(old_sl1e);
> +
> +    if ( !sh_l1e_is_magic(old_sl1e) &&
> +         (l1e_get_flags(old_sl1e) & _PAGE_PRESENT) &&
> +         mfn_valid(old_mfn))
>      {
> -        unsigned long i = gfn - dirty_vram->begin_pfn;
> -        struct page_info *page = mfn_to_page(mfn);
> -        
> -        if ( (page->u.inuse.type_info & PGT_count_mask) == 1 )
> -            /* Initial guest reference, record it */
> -            dirty_vram->sl1ma[i] = pfn_to_paddr(mfn_x(sl1mfn))
> -                | ((unsigned long)sl1e & ~PAGE_MASK);
> +        old_gfn = mfn_to_gfn(d, old_mfn);
>      }
> -}
> -
> -static inline void shadow_vram_put_l1e(shadow_l1e_t old_sl1e,
> -                                       shadow_l1e_t *sl1e,
> -                                       mfn_t sl1mfn,
> -                                       struct domain *d)
> -{
> -    mfn_t mfn = shadow_l1e_get_mfn(old_sl1e);
> -    int flags = shadow_l1e_get_flags(old_sl1e);
> -    unsigned long gfn;
> -    struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
> -
> -    if ( !dirty_vram         /* tracking disabled? */
> -         || !(flags & _PAGE_RW) /* read-only mapping? */
> -         || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
> -        return;
> -
> -    gfn = mfn_to_gfn(d, mfn);
> -    /* Page sharing not supported on shadow PTs */
> -    BUG_ON(SHARED_M2P(gfn));
> -
> -    if ( (gfn >= dirty_vram->begin_pfn) && (gfn <
dirty_vram->end_pfn) )
> +    
> +    new_mfn = shadow_l1e_get_mfn(new_sl1e);
> +    if ( !sh_l1e_is_magic(new_sl1e) &&
> +         (l1e_get_flags(new_sl1e) & _PAGE_PRESENT) &&
> +         mfn_valid(new_mfn))
>      {
> -        unsigned long i = gfn - dirty_vram->begin_pfn;
> -        struct page_info *page = mfn_to_page(mfn);
> -        int dirty = 0;
> -        paddr_t sl1ma = pfn_to_paddr(mfn_x(sl1mfn))
> -            | ((unsigned long)sl1e & ~PAGE_MASK);
> +        new_gfn = mfn_to_gfn(d, new_mfn);
> +    }
>  
> -        if ( (page->u.inuse.type_info & PGT_count_mask) == 1 )
> -        {
> -            /* Last reference */
> -            if ( dirty_vram->sl1ma[i] == INVALID_PADDR ) {
> -                /* We didn''t know it was that one, let''s
say it is dirty */
> -                dirty = 1;
> -            }
> -            else
> -            {
> -                ASSERT(dirty_vram->sl1ma[i] == sl1ma);
> -                dirty_vram->sl1ma[i] = INVALID_PADDR;
> -                if ( flags & _PAGE_DIRTY )
> -                    dirty = 1;
> -            }
> -        }
> -        else
> +    if ( old_gfn == new_gfn ) return;
> +
> +    if ( VALID_M2P(old_gfn) )
> +        if ( dirty_vram_range_update(d, old_gfn, sl1ma, 0/*clear*/) )
>          {
> -            /* We had more than one reference, just consider the page
dirty. */
> -            dirty = 1;
> -            /* Check that it''s not the one we recorded. */
> -            if ( dirty_vram->sl1ma[i] == sl1ma )
> -            {
> -                /* Too bad, we remembered the wrong one... */
> -                dirty_vram->sl1ma[i] = INVALID_PADDR;
> -            }
> -            else
> -            {
> -                /* Ok, our recorded sl1e is still pointing to this page,
let''s
> -                 * just hope it will remain. */
> -            }
> +            SHADOW_PRINTK("gfn %lx (mfn %lx) cleared vram
pte\n",
> +                          old_gfn, mfn_x(old_mfn));
>          }
> -        if ( dirty )
> +
> +    if ( VALID_M2P(new_gfn) )
> +        if ( dirty_vram_range_update(d, new_gfn, sl1ma, 1/*set*/) )
>          {
> -            dirty_vram->dirty_bitmap[i / 8] |= 1 << (i % 8);
> -            dirty_vram->last_dirty = NOW();
> +            SHADOW_PRINTK("gfn %lx (mfn %lx) set vram pte\n",
> +                          new_gfn, mfn_x(new_mfn));
>          }
> -    }
>  }
>  
>  static int shadow_set_l1e(struct vcpu *v, 
> @@ -1211,12 +1167,13 @@ static int shadow_set_l1e(struct vcpu *v,
>                  shadow_l1e_remove_flags(new_sl1e, _PAGE_RW);
>                  /* fall through */
>              case 0:
> -                shadow_vram_get_l1e(new_sl1e, sl1e, sl1mfn, d);
>                  break;
>              }
>          }
>      } 
>  
> +    shadow_vram_fix_l1e(old_sl1e, new_sl1e, sl1e, sl1mfn, d);
> +
>      /* Write the new entry */
>      shadow_write_entries(sl1e, &new_sl1e, 1, sl1mfn);
>      flags |= SHADOW_SET_CHANGED;
> @@ -1231,7 +1188,6 @@ static int shadow_set_l1e(struct vcpu *v,
>           * trigger a flush later. */
>          if ( shadow_mode_refcounts(d) ) 
>          {
> -            shadow_vram_put_l1e(old_sl1e, sl1e, sl1mfn, d);
>              shadow_put_page_from_l1e(old_sl1e, d);
>              TRACE_SHADOW_PATH_FLAG(TRCE_SFLAG_SHADOW_L1_PUT_REF);
>          } 
> @@ -2018,7 +1974,6 @@ void sh_destroy_l1_shadow(struct vcpu *v, mfn_t smfn)
>          SHADOW_FOREACH_L1E(sl1mfn, sl1e, 0, 0, {
>              if ( (shadow_l1e_get_flags(*sl1e) & _PAGE_PRESENT)
>                   && !sh_l1e_is_magic(*sl1e) ) {
> -                shadow_vram_put_l1e(*sl1e, sl1e, sl1mfn, d);
>                  shadow_put_page_from_l1e(*sl1e, d);
>              }
>          });
> @@ -4336,6 +4291,37 @@ int sh_rm_mappings_from_l1(struct vcpu *v, mfn_t
sl1mfn, mfn_t target_mfn)
>      return done;
>  }
>  
> +
> +int sh_find_vram_mappings_in_l1(struct vcpu *v,
> +                                mfn_t sl1mfn,
> +                                unsigned long begin_pfn,
> +                                unsigned long end_pfn,
> +                                int *removed)
> +/* Find all VRAM mappings in this shadow l1 table */
> +{
> +    struct domain *d = v->domain;
> +    shadow_l1e_t *sl1e;
> +    int done = 0;
> +
> +    /* only returns _PAGE_PRESENT entries */
> +    SHADOW_FOREACH_L1E(sl1mfn, sl1e, 0, done, 
> +    {
> +        unsigned long gfn;
> +        mfn_t gmfn = shadow_l1e_get_mfn(*sl1e);
> +        if ( !mfn_valid(gmfn) )
> +            continue;
> +        gfn = mfn_to_gfn(d, gmfn);
> +        if ( VALID_M2P(gfn) && (begin_pfn <= gfn) &&
(gfn < end_pfn) )
> +        {
> +            paddr_t sl1ma > +               
pfn_to_paddr(mfn_x(sl1mfn)) |
> +                ( (unsigned long)sl1e & ~PAGE_MASK );
> +            dirty_vram_range_update(v->domain, gfn, sl1ma, 1/*set*/);
> +        }
> +    });
> +    return 0;
> +}
> +
> 
/**************************************************************************/
>  /* Functions to excise all pointers to shadows from higher-level shadows.
*/
>  
> diff --git a/xen/arch/x86/mm/shadow/multi.h
b/xen/arch/x86/mm/shadow/multi.h
> index 835121e..436a4ac 100644
> --- a/xen/arch/x86/mm/shadow/multi.h
> +++ b/xen/arch/x86/mm/shadow/multi.h
> @@ -66,7 +66,12 @@ SHADOW_INTERNAL_NAME(sh_rm_write_access_from_l1,
GUEST_LEVELS)
>  extern int
>  SHADOW_INTERNAL_NAME(sh_rm_mappings_from_l1, GUEST_LEVELS)
>      (struct vcpu *v, mfn_t sl1mfn, mfn_t target_mfn);
> -
> +extern int
> +SHADOW_INTERNAL_NAME(sh_find_vram_mappings_in_l1, GUEST_LEVELS)
> +     (struct vcpu *v, mfn_t sl1mfn, 
> +      unsigned long begin_pfn,
> +      unsigned long end_pfn,
> +      int *removed);
>  extern void
>  SHADOW_INTERNAL_NAME(sh_clear_shadow_entry, GUEST_LEVELS)
>      (struct vcpu *v, void *ep, mfn_t smfn);
> diff --git a/xen/arch/x86/mm/shadow/types.h
b/xen/arch/x86/mm/shadow/types.h
> index 43ce1db..5b0f9f7 100644
> --- a/xen/arch/x86/mm/shadow/types.h
> +++ b/xen/arch/x86/mm/shadow/types.h
> @@ -229,6 +229,7 @@ static inline shadow_l4e_t shadow_l4e_from_mfn(mfn_t
mfn, u32 flags)
>  #define sh_update_cr3              INTERNAL_NAME(sh_update_cr3)
>  #define sh_rm_write_access_from_l1
INTERNAL_NAME(sh_rm_write_access_from_l1)
>  #define sh_rm_mappings_from_l1     INTERNAL_NAME(sh_rm_mappings_from_l1)
> +#define sh_find_vram_mappings_in_l1
INTERNAL_NAME(sh_find_vram_mappings_in_l1)
>  #define sh_remove_l1_shadow        INTERNAL_NAME(sh_remove_l1_shadow)
>  #define sh_remove_l2_shadow        INTERNAL_NAME(sh_remove_l2_shadow)
>  #define sh_remove_l3_shadow        INTERNAL_NAME(sh_remove_l3_shadow)
> diff --git a/xen/include/asm-x86/dirty_vram.h
b/xen/include/asm-x86/dirty_vram.h
> new file mode 100644
> index 0000000..727af05
> --- /dev/null
> +++ b/xen/include/asm-x86/dirty_vram.h
> @@ -0,0 +1,227 @@
>
+/****************************************************************************
> + * include/asm-x86/dirty_vram.h
> + *
> + * Interface for tracking dirty VRAM pages
> + *
> + * Copyright (c) 2012 Citrix Systems, Inc. (Robert Phillips)
> + * Parts of this code are Copyright (c) 2007 Advanced Micro Devices (Wei
Huang)
> + * Parts of this code are Copyright (c) 2006 by XenSource Inc.
> + * Parts of this code are Copyright (c) 2006 by Michael A Fetterman
> + * Parts based on earlier work by Michael A Fetterman, Ian Pratt et al.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 
USA
> + */
> +
> +#ifndef _DIRTY_VRAM_H
> +#define _DIRTY_VRAM_H
> +
> +/*
> + * In shadow mode we need to bookkeep all the L1 page table entries that
> + * map a frame buffer page.  Struct dv_paddr_link does this by
> + * recording the address of a L1 page table entry for some frame buffer
page.
> + * Also has a link to additional pl entries if the frame buffer page
> + * has multiple mappings.
> + * In practice very few pages have multiple mappings.
> + * But to rule out some pathological situation, we limit the number of
> + * mappings we''re willing to bookkeep.
> + */
> +
> +#define DV_ADDR_LINK_LIST_LIMIT 64
> +
> +typedef struct dv_paddr_link {
> +    paddr_t sl1ma;
> +    paddr_t pl_next;
> +} dv_paddr_link_t;
> +
> +typedef struct dv_pl_entry {
> +    dv_paddr_link_t mapping;
> +    bool_t stuck_dirty;
> +} dv_pl_entry_t;
> +
> +/*
> + * This defines an extension page of pl entries for FB pages with multiple
> + * mappings. All such pages (of a domain) are linked together.
> + */
> +typedef struct dv_paddr_link_ext {
> +    paddr_t ext_link;
> +    dv_paddr_link_t entries[ ( PAGE_SIZE - sizeof( paddr_t ) ) /
> +                             sizeof( dv_paddr_link_t ) ];
> +} dv_paddr_link_ext_t;
> +
> +/*
> + * This defines a single frame buffer range.  It bookkeeps all the
> + * level 1 PTEs that map guest pages within that range.
> + * All such ranges (of a domain) are linked together.
> + */
> +typedef struct dv_range {
> +    struct list_head range_link; /* the several ranges form a linked list
*/
> +    unsigned long begin_pfn;
> +    unsigned long end_pfn;
> +    dv_pl_entry_t *pl_tab; /* table has 1 pl entry per pfn in range */
> +    int mappings_hwm; /* high water mark of max mapping count */
> +    unsigned int dirty_count;
> +} dv_range_t;
> +
> +/*
> + * This contains all the data structures required by a domain to
> + * bookkeep the dirty pages within its frame buffers.
> + */
> +typedef struct dv_dirty_vram {
> +    struct list_head range_head; /* head of the linked list of ranges */
> +    paddr_t ext_head;/* head of list of extension pages */
> +    paddr_t pl_free; /* free list of pl''s within extension pages
*/
> +    int nr_ranges;   /* bookkeeps number of ranges */
> +    int ranges_hwm;  /* high water mark of max number of ranges */
> +} dv_dirty_vram_t;
> +
> +/* Allocates domain''s dirty_vram structure */
> +dv_dirty_vram_t *
> +dirty_vram_alloc(struct domain *d);
> +
> +/*
> + * Returns domain''s dirty_vram structure,
> + * allocating it if necessary
> + */
> +dv_dirty_vram_t *
> +dirty_vram_find_or_alloc(struct domain *d);
> +
> +/* Frees domain''s dirty_vram structure */
> +void dirty_vram_free(struct domain *d);
> +
> +/* Returns dirty vram range containing gfn, NULL if none */
> +struct dv_range *
> +dirty_vram_range_find_gfn(struct domain *d,
> +                          unsigned long gfn);
> +
> +/*
> + * Returns dirty vram range matching [ begin_pfn .. begin_pfn+nr ),
> + * NULL if none
> + */
> +dv_range_t *
> +dirty_vram_range_find(struct domain *d,
> +                      unsigned long begin_pfn,
> +                      unsigned long nr);
> +
> +/*
> + * Allocate dirty vram range containing [ begin_pfn .. begin_pfn+nr ),
> + * freeing any existing range that overlaps the new range.
> + */
> +dv_range_t *
> +dirty_vram_range_alloc(struct domain *d,
> +                       unsigned long begin_pfn,
> +                       unsigned long nr);
> +
> +/*
> + * Returns dirty vram range matching [ begin_pfn .. begin_pfn+nr ),
> + * creating a range if none already exists and
> + * freeing any existing range that overlaps the new range.
> + */
> +dv_range_t *
> +dirty_vram_range_find_or_alloc(struct domain *d,
> +                               unsigned long begin_pfn,
> +                               unsigned long nr);
> +
> +void dirty_vram_range_free(struct domain *d,
> +                           dv_range_t *range);
> +
> +/* Bookkeep PTE address of a frame buffer page */
> +int dirty_vram_range_update(struct domain *d,
> +                            unsigned long gfn,
> +                            paddr_t sl1ma,
> +                            int set);
> +
> +/*
> + * smfn is no longer a shadow page.  Remove it from any
> + * dirty vram range mapping.
> + */
> +void
> +dirty_vram_delete_shadow(struct vcpu *v,
> +                         unsigned long gfn,
> +                         unsigned int shadow_type,
> +                         mfn_t smfn);
> +
> +
> +/*
> + * Scan all the L1 tables looking for VRAM mappings.
> + * Record them in the domain''s dv_dirty_vram structure
> + */
> +void sh_find_all_vram_mappings(struct vcpu *v,
> +                               dv_range_t *range);
> +
> +/*
> + * Free a paddr_link struct, given address of its
> + * predecessor in singly-linked list
> + */
> +dv_paddr_link_t *
> +free_paddr_link(struct domain *d,
> +                paddr_t* ppl,
> +                dv_paddr_link_t *pl);
> +
> +
> +/* Enable VRAM dirty tracking. */
> +int
> +shadow_track_dirty_vram(struct domain *d,
> +                        unsigned long first_pfn,
> +                        unsigned long nr,
> +                        XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
> +
> +int
> +hap_track_dirty_vram(struct domain *d,
> +                     unsigned long begin_pfn,
> +                     unsigned long nr,
> +                     XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
> +
> +void
> +hap_clean_vram_tracking_range(struct domain *d,
> +                              unsigned long begin_pfn,
> +                              unsigned long nr,
> +                              uint8_t *dirty_bitmap);
> +
> +/* Unmap a va and map a ma.
> + * This is used when walking a linked list in which
> + * the links are stored as ma''s rather than va''s.
> + * Each step in the walk unmaps the va returned
> + * by the previous iteration and maps the next link.
> + *
> + * Unmaps @old_va if not NULL.
> + *
> + * If @new_va is not INVALID_PADDR, maps it and returns the resulting
> + * va (which must be subsequently unmapped.) Else returns NULL.
> + */
> +void *
> +remap_maddr(void *old_va, paddr_t new_ma);
> +
> +
> +/* Like the above but it acquires a mapping
> + * (possibly an additional mapping) on @new_va.
> + *
> + * Returns @new_va.
> + *
> + * Does no unmapping if @old_va is NULL.
> + * Does no mapping if @new_va is NULL.
> + */
> +void *
> +remap_vaddr(void *old_va, void *new_va);
> +
> +#endif /* _DIRTY_VRAM_H */
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/asm-x86/hap.h b/xen/include/asm-x86/hap.h
> index 916a35b..3e3a1f5 100644
> --- a/xen/include/asm-x86/hap.h
> +++ b/xen/include/asm-x86/hap.h
> @@ -57,10 +57,6 @@ void  hap_final_teardown(struct domain *d);
>  void  hap_teardown(struct domain *d);
>  void  hap_vcpu_init(struct vcpu *v);
>  void  hap_logdirty_init(struct domain *d);
> -int   hap_track_dirty_vram(struct domain *d,
> -                           unsigned long begin_pfn,
> -                           unsigned long nr,
> -                           XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
>  
>  extern const struct paging_mode *hap_paging_get_mode(struct vcpu *);
>  
> diff --git a/xen/include/asm-x86/hvm/domain.h
b/xen/include/asm-x86/hvm/domain.h
> index 27b3de5..0cc7b05 100644
> --- a/xen/include/asm-x86/hvm/domain.h
> +++ b/xen/include/asm-x86/hvm/domain.h
> @@ -74,7 +74,7 @@ struct hvm_domain {
>      struct list_head       pinned_cacheattr_ranges;
>  
>      /* VRAM dirty support. */
> -    struct sh_dirty_vram *dirty_vram;
> +    struct dv_dirty_vram  *dirty_vram;
>  
>      /* If one of vcpus of this domain is in no_fill_mode or
>       * mtrr/pat between vcpus is not the same, set is_in_uc_mode
> diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
> index c3a8848..e22df38 100644
> --- a/xen/include/asm-x86/paging.h
> +++ b/xen/include/asm-x86/paging.h
> @@ -154,9 +154,13 @@ void paging_log_dirty_init(struct domain *d,
>                             int  (*disable_log_dirty)(struct domain *d),
>                             void (*clean_dirty_bitmap)(struct domain *d));
>  
> -/* mark a page as dirty */
> +/* mark a gmfn as dirty, a wrapper around marking a gpfn as dirty */
>  void paging_mark_dirty(struct domain *d, unsigned long guest_mfn);
>  
> +/* mark a gpfn as dirty */
> +void paging_mark_dirty_gpfn(struct domain *d, unsigned long gpfn);
> +
> +
>  /* is this guest page dirty? 
>   * This is called from inside paging code, with the paging lock held. */
>  int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
> @@ -183,15 +187,6 @@ int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
>  #define L4_LOGDIRTY_IDX(pfn) 0
>  #endif
>  
> -/* VRAM dirty tracking support */
> -struct sh_dirty_vram {
> -    unsigned long begin_pfn;
> -    unsigned long end_pfn;
> -    paddr_t *sl1ma;
> -    uint8_t *dirty_bitmap;
> -    s_time_t last_dirty;
> -};
> -
> 
/*****************************************************************************
>   * Entry points into the paging-assistance code */
>  
> diff --git a/xen/include/asm-x86/shadow.h b/xen/include/asm-x86/shadow.h
> index 2eb6efc..940d7fd 100644
> --- a/xen/include/asm-x86/shadow.h
> +++ b/xen/include/asm-x86/shadow.h
> @@ -62,12 +62,6 @@ void shadow_vcpu_init(struct vcpu *v);
>  /* Enable an arbitrary shadow mode.  Call once at domain creation. */
>  int shadow_enable(struct domain *d, u32 mode);
>  
> -/* Enable VRAM dirty bit tracking. */
> -int shadow_track_dirty_vram(struct domain *d,
> -                            unsigned long first_pfn,
> -                            unsigned long nr,
> -                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
> -
>  /* Handler for shadow control ops: operations from user-space to enable
>   * and disable ephemeral shadow modes (test mode and log-dirty mode) and
>   * manipulate the log-dirty bitmap. */
> -- 
> 1.7.9.5
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Hi,

At 15:48 -0500 on 01 Mar (1362152937), Robert Phillips
wrote:
> Support is provided for both shadow and hardware assisted paging (HAP)
> modes. This code bookkeeps the set of video frame buffers (vram),
> detects when the guest has modified any of those buffers and, upon request,
> returns a bitmap of the modified pages.
> This lets other software components re-paint the portions of the monitor
> (or monitors) that have changed.
> Each monitor has a frame buffer of some size at some position
> in guest physical memory.
> The set of frame buffers being tracked can change over time as monitors
> are plugged and unplugged.
> 
> This is the 9th version of this patch.
I''m afraid we''ll need to go to a tenth.  During VM shutdown of
a
shadow-pagetables winXP VM, on AMD:

(XEN) Xen BUG at domain_page.c:143
(XEN) ----[ Xen-4.3-unstable  x86_64  debug=y  Tainted:    C ]----
(XEN) CPU:    2
(XEN) RIP:    e008:[<ffff82c4c015efd2>] map_domain_page+0x423/0x4eb
(XEN) RFLAGS: 0000000000010046   CONTEXT: hypervisor
(XEN) rax: 0000000000000060   rbx: ffff83021797d000   rcx: 0000000000000000
(XEN) rdx: 0000000000000060   rsi: 0000000000000060   rdi: 0000000000000040
(XEN) rbp: ffff83021d60fa68   rsp: ffff83021d60fa28   r8:  00000000ffffffff
(XEN) r9:  ffff820060006008   r10: 0000000000000000   r11: 000000000016a515
(XEN) r12: ffff8300df51d000   r13: 000000000021f9df   r14: 0000000000000060
(XEN) r15: 0000000000000007   cr0: 0000000080050033   cr4: 00000000000006f0
(XEN) cr3: 00000002166c7000   cr2: ffff880002756830
(XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e010   cs: e008
(XEN) Xen stack trace from rsp=ffff83021d60fa28:
(XEN)    ffff83021797d2d8 0000000000000286 ffff83021d60fa78 ffff83021f9df1f8
(XEN)    0000000000000000 000000000021fbb6 ffff83021f9df0e0 00000000000000d8
(XEN)    ffff83021d60fa88 ffff82c4c01e96c7 0000000000000006 ffff83021f9df1e0
(XEN)    ffff83021d60fae8 ffff82c4c01f90a3 ffff83021f9df0a0 ffff83021f9df0a0
(XEN)    ffff83021f991000 0000000000000009 00000000002166e7 0000000000000004
(XEN)    000000000016a515 ffff83021f991000 ffff82e0043f76c0 ffff8300df688000
(XEN)    ffff83021d60fb38 ffff82c4c02077c8 0000000000000093 000000000021fbb6
(XEN)    ffff82c4c0125159 0000000000000000 0000000000000601 000000000021f65a
(XEN)    ffff82e0043f76c0 ffff82e000000000 ffff83021d60fb68 ffff82c4c01f2acc
(XEN)    0000000000162aab 000000000021f65a 000000000021f65a ffff820040046008
(XEN)    ffff83021d60fbe8 ffff82c4c0207680 ffff83021d608000 ffff820040046000
(XEN)    ffff8300df688000 000000000021f65a 000000021f65a000 000000000021fbb6
(XEN)    0000000200000000 001040001d60fbc8 ffff82c4c0125159 0000000000000000
(XEN)    ffff82e0043ecb40 ffff82e000000000 ffff83021f991000 ffff82e0043ecb20
(XEN)    ffff83021d60fc18 ffff82c4c01f2ad7 000000fc00000000 0000000000000000
(XEN)    0000000000000000 000000000021f65a ffff83021d60fc78 ffff82c4c01f3c0c
(XEN)    0000000100000000 ffff8300df688000 0000000000000286 ffff83021d60fc58
(XEN)    ffff82c4c0125159 ffff83021f991000 0000000000000000 0000000000000000
(XEN)    00007d2000000000 ffff83021d608000 ffff83021d60fcc8 ffff82c4c01f3f8b
(XEN)    ffff83021d60fcc8 ffff82c4c012d34c ffff82c4c0125416 0000000000000003
(XEN) Xen call trace:
(XEN)    [<ffff82c4c015efd2>] map_domain_page+0x423/0x4eb
(XEN)    [<ffff82c4c01e96c7>] remap_vaddr+0x2b/0x35
(XEN)    [<ffff82c4c01f90a3>] dirty_vram_delete_shadow+0xac/0x18d
(XEN)    [<ffff82c4c02077c8>] sh_destroy_l1_shadow__guest_3+0x10a/0x25d
(XEN)    [<ffff82c4c01f2acc>] sh_destroy_shadow+0x113/0x194
(XEN)    [<ffff82c4c0207680>] sh_destroy_l2_shadow__guest_3+0x38a/0x3c8
(XEN)    [<ffff82c4c01f2ad7>] sh_destroy_shadow+0x11e/0x194
(XEN)    [<ffff82c4c01f3c0c>] _shadow_prealloc+0x45a/0x678
(XEN)    [<ffff82c4c01f3f8b>] sh_set_allocation+0x161/0x2a0
(XEN)    [<ffff82c4c01f893d>] shadow_teardown+0x25e/0x3b4
(XEN)    [<ffff82c4c01dce35>] paging_teardown+0x29/0x40
(XEN)    [<ffff82c4c015e768>] domain_relinquish_resources+0xae/0x2e6
(XEN)    [<ffff82c4c01055b4>] domain_kill+0x87/0xe1
(XEN)    [<ffff82c4c0103a5b>] do_domctl+0xaa3/0x11e8
(XEN)    [<ffff82c4c022601b>] syscall_enter+0xeb/0x145
(XEN)    
(XEN) 
(XEN) ****************************************
(XEN) Panic on CPU 2:
(XEN) Xen BUG at domain_page.c:143
(XEN) ****************************************

( config: 
 name = "winxp"
 builder = "hvm"
 memory = 4096
 vcpus = 2
 hap = 0
 vif = [ ''type=ioemu, bridge=xenbr0'' ]
 disk = [ ''phy:/dev/loop0,hda,w'',
''file:/root/winxpsp3.iso,hdc:cdrom,r'' ]
 usb = 1
 usbdevice = "tablet"
)

And in normal operation of a 64-bit Win7 VM, on Intel:

(XEN) Xen BUG at domain_page.c:143
(XEN) ----[ Xen-4.3-unstable  x86_64  debug=y  Not tainted ]----
(XEN) CPU:    5
(XEN) RIP:    e008:[<ffff82c4c015efd2>] map_domain_page+0x423/0x4eb
(XEN) RFLAGS: 0000000000010046   CONTEXT: hypervisor
(XEN) rax: 0000000000000000   rbx: ffff83023d508000   rcx: 00000000ffffffff
(XEN) rdx: 0000000000000000   rsi: 0000000000000000   rdi: ffff8300bf2fb338
(XEN) rbp: ffff83023d527c28   rsp: ffff83023d527be8   r8:  ffffffffffffffff
(XEN) r9:  ffff820060006008   r10: 0000000000000000   r11: 0180000000000000
(XEN) r12: ffff8300bf2fb000   r13: 00000000001cd200   r14: 0000000000000080
(XEN) r15: 0000000000000000   cr0: 0000000080050033   cr4: 00000000000026f0
(XEN) cr3: 000000023f3d6000   cr2: ffff88002da162b0
(XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e010   cs: e008
(XEN) Xen stack trace from rsp=ffff83023d527be8:
(XEN)    ffff83023d5082d8 0000000000000286 0000000000000069 ffff8301cd2006a8
(XEN)    0000000000000007 00000000000f0047 000000020f0be038 ffff83023f213d90
(XEN)    ffff83023d527c48 ffff82c4c01e96c7 00000000001d6a00 ffff82004006e038
(XEN)    ffff83023d527cc8 ffff82c4c01e9c18 ffff8300bf2fb000 000000000020f0be
(XEN)    000000000000006e 00000000000006a8 ffff830200000001 00000000000f0047
(XEN)    ffff83023fca0000 0000000000000000 00000000001d6a00 ffff82004006e038
(XEN)    0000000000000007 00000000000f0047 000ffffffffff000 ffff83023fca0000
(XEN)    ffff83023d527d38 ffff82c4c0212bf9 ffff82004000c000 ffff82004006e000
(XEN)    000000020f0be000 ffff8300bf2ee000 00000000000f0160 00000000000f0000
(XEN)    ffff83023f213d50 ffff82e0041e17c0 0000000000000001 00007d2000000000
(XEN)    ffff8300bf2ee000 00000000000f0000 ffff83023d527da8 ffff82c4c01f92ca
(XEN)    ffff83023f213d50 ffff83023fca0000 0000000000000390 00000000000f0160
(XEN)    ffff83023f213d90 00000000000f0160 ffff82c4c0125416 0000000000000000
(XEN)    0000000000000160 00000000000f0000 00007f3489409004 00000000000f0000
(XEN)    ffff83023d527e48 ffff82c4c01ea132 0000000100000001 ffff83023d508000
(XEN)    ffff82e0046b1b40 00000000002358da 00007f3486a84004 ffff83023f213d90
(XEN)    ffff83023fca0ad0 ffff82e0046b1b40 0000000000000000 ffff82c4c017589c
(XEN)    ffff83023fca0000 000000000000000f 0000000000237487 ffff83023d508000
(XEN)    ffffffffffffffea 0000000000000006 00007f3489409004 00000000000f0000
(XEN)    ffff83023d527ef8 ffff82c4c01b4315 ffff83023d527e68 ffff82c4c016d072
(XEN) Xen call trace:
(XEN)    [<ffff82c4c015efd2>] map_domain_page+0x423/0x4eb
(XEN)    [<ffff82c4c01e96c7>] remap_vaddr+0x2b/0x35
(XEN)    [<ffff82c4c01e9c18>] dirty_vram_range_update+0x96/0x3bc
(XEN)    [<ffff82c4c0212bf9>]
sh_find_vram_mappings_in_l1__guest_4+0x107/0x135
(XEN)    [<ffff82c4c01f92ca>] sh_find_all_vram_mappings+0x146/0x19e
(XEN)    [<ffff82c4c01ea132>] shadow_track_dirty_vram+0x1f4/0x46e
(XEN)    [<ffff82c4c01b4315>] do_hvm_op+0xf39/0x1f43
(XEN)    [<ffff82c4c022601b>] syscall_enter+0xeb/0x145
(XEN)    
(XEN) 
(XEN) ****************************************
(XEN) Panic on CPU 5:
(XEN) Xen BUG at domain_page.c:143
(XEN) ****************************************

( config: 
 name = "win7"
 builder = "hvm"
 memory = 6000
 vcpus = 2
 vif = [ ''type=ioemu, bridge=xenbr0'' ]
 disk = [ ''file:/root/win7.img,hda,w'',
''file:/root/win7sp1-x64.iso,hdc:cdrom,r'' ]
 usb = 1
 usbdevice = "tablet"
 hap = 0
) 

Those were the first two VMs I tried, so I don''t know if anything else
works.

Since we''re going to v10 anway, can you please make the new
remap_[vm]addr functions static?  They''re not used outside
dirty_vram.c.

Also, please drop the mm/p2m.c changes, which are just whitespace
adjustments now, and not related to the rest of the patch. 

Cheers,

Tim.

On Fri, Mar 01, 2013 at 08:48:57PM +0000, Robert Phillips
wrote:
> Support is provided for both shadow and hardware assisted paging (HAP)
> modes. This code bookkeeps the set of video frame buffers (vram),
> detects when the guest has modified any of those buffers and, upon request,
> returns a bitmap of the modified pages.
> This lets other software components re-paint the portions of the monitor
> (or monitors) that have changed.
> Each monitor has a frame buffer of some size at some position
> in guest physical memory.
> The set of frame buffers being tracked can change over time as monitors
> are plugged and unplugged.
> 
> This is the 9th version of this patch.
Hi Robert, any news for v10 of this patch?

Wei.

On Thu, Oct 10, 2013 at 10:48 AM, Wei Liu <wei.liu2@citrix.com> wrote:
> On Fri, Mar 01, 2013 at 08:48:57PM +0000, Robert Phillips wrote:
> > Support is provided for both shadow and hardware assisted paging (HAP)
> > modes. This code bookkeeps the set of video frame buffers (vram),
> > detects when the guest has modified any of those buffers and, upon
> request,
> > returns a bitmap of the modified pages.
> > This lets other software components re-paint the portions of the
monitor
> > (or monitors) that have changed.
> > Each monitor has a frame buffer of some size at some position
> > in guest physical memory.
> > The set of frame buffers being tracked can change over time as
monitors
> > are plugged and unplugged.
> >
> > This is the 9th version of this patch.
>
> Hi Robert, any news for v10 of this patch?
>
Robert has been asked to stop work on this, after so many submissions.
He has since been focusing on other projects - I don''t think there has
been
any additional effort put forth to get this upstream.

We (XenClient) maintain a patch queue, and will continue to carry this
patch, for now.

Ben


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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

On Thu, Oct 10, 2013 at 10:58:12AM -0400, Ben Guthro
wrote:
> On Thu, Oct 10, 2013 at 10:48 AM, Wei Liu <wei.liu2@citrix.com>
wrote:
> 
> > On Fri, Mar 01, 2013 at 08:48:57PM +0000, Robert Phillips wrote:
> > > Support is provided for both shadow and hardware assisted paging
(HAP)
> > > modes. This code bookkeeps the set of video frame buffers (vram),
> > > detects when the guest has modified any of those buffers and,
upon
> > request,
> > > returns a bitmap of the modified pages.
> > > This lets other software components re-paint the portions of the
monitor
> > > (or monitors) that have changed.
> > > Each monitor has a frame buffer of some size at some position
> > > in guest physical memory.
> > > The set of frame buffers being tracked can change over time as
monitors
> > > are plugged and unplugged.
> > >
> > > This is the 9th version of this patch.
> >
> > Hi Robert, any news for v10 of this patch?
> >
> 
> Robert has been asked to stop work on this, after so many submissions.
> He has since been focusing on other projects - I don''t think there
has been
> any additional effort put forth to get this upstream.
> 
OK, thanks for the update.
> We (XenClient) maintain a patch queue, and will continue to carry this
> patch, for now.
> 
So any new change to this patch? Or you just carry it as-is? I suppose
there should be some changes to fix Tim''s test cases.

Wei.
> Ben