George Dunlap
2008-Dec-23 13:45 UTC
[Xen-devel] [RFC][PATCH] 3/9 Populate-on-demand memory: PoD core
Core of populate-on-demand functionality:
* Introduce a populate-on-demand type
* Call p2m_demand_populate() when gfn_to_mfn() encounters PoD entries
* Return p2m memory to the domain list for freeing during domain destruction
* Audit p2m checks our PoD-entry reference-counting
* Add PoD information to the ''q'' debug key
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
diff -r e61e4075a710 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Wed Dec 17 12:59:51 2008 +0000
+++ b/xen/arch/x86/domain.c Fri Dec 19 17:51:53 2008 +0000
@@ -147,6 +147,11 @@
_p(page_to_mfn(page)),
page->count_info, page->u.inuse.type_info);
}
+ }
+
+ if ( is_hvm_domain(d) )
+ {
+ p2m_pod_dump_data(d);
}
list_for_each_entry ( page, &d->xenpage_list, list )
diff -r e61e4075a710 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Wed Dec 17 12:59:51 2008 +0000
+++ b/xen/arch/x86/mm/p2m.c Fri Dec 19 17:51:53 2008 +0000
@@ -118,9 +118,16 @@
return flags;
case p2m_mmio_direct:
return flags | P2M_BASE_FLAGS | _PAGE_RW | _PAGE_PCD;
+ case p2m_populate_on_demand:
+ return flags;
}
}
+#if P2M_AUDIT
+static void audit_p2m(struct domain *d);
+#else
+# define audit_p2m(_d) do { (void)(_d); } while(0)
+#endif /* P2M_AUDIT */
// Find the next level''s P2M entry, checking for out-of-range
gfn''s...
// Returns NULL on error.
@@ -162,7 +169,8 @@
shift, max)) )
return 0;
- if ( !(l1e_get_flags(*p2m_entry) & _PAGE_PRESENT) )
+ /* PoD: Not present doesn''t imply empty. */
+ if ( !l1e_get_flags(*p2m_entry) )
{
struct page_info *pg = d->arch.p2m->alloc_page(d);
if ( pg == NULL )
@@ -197,7 +205,7 @@
}
}
- ASSERT(l1e_get_flags(*p2m_entry) & _PAGE_PRESENT);
+ ASSERT(l1e_get_flags(*p2m_entry) & (_PAGE_PRESENT|_PAGE_PSE));
/* split single large page into 4KB page in P2M table */
if ( type == PGT_l1_page_table && (l1e_get_flags(*p2m_entry) &
_PAGE_PSE) )
@@ -240,6 +248,236 @@
*table = next;
return 1;
+}
+
+/*
+ * Populate-on-demand functionality
+ */
+int
+p2m_pod_cache_add(struct domain *d,
+ struct page_info *page,
+ unsigned long order)
+{
+ int i;
+ struct page_info *p;
+ struct p2m_domain *p2md = d->arch.p2m;
+
+#ifndef NDEBUG
+ mfn_t mfn;
+
+ mfn = page_to_mfn(page);
+
+ /* Check to make sure this is a contiguous region */
+ if( mfn_x(mfn) & ((1 << order) - 1) )
+ {
+ printk("%s: mfn %lx not aligned order %lu! (mask %lx)\n",
+ __func__, mfn_x(mfn), order, ((1UL << order) - 1));
+ return -1;
+ }
+
+ for(i=0; i < 1 << order ; i++) {
+ struct domain * od;
+
+ p = mfn_to_page(_mfn(mfn_x(mfn) + i));
+ od = page_get_owner(p);
+ if(od != d)
+ {
+ printk("%s: mfn %lx expected owner d%d, got owner
d%d!\n",
+ __func__, mfn_x(mfn), d->domain_id,
+ od?od->domain_id:-1);
+ return -1;
+ }
+ }
+#endif
+
+ spin_lock(&d->page_alloc_lock);
+
+ /* First, take all pages off the domain list */
+ for(i=0; i < 1 << order ; i++)
+ {
+ p = page + i;
+ list_del(&p->list);
+ }
+
+ /* Then add the first one to the appropriate populate-on-demand list */
+ switch(order)
+ {
+ case 9:
+ list_add_tail(&page->list, &p2md->pod.super); /* lock:
page_alloc */
+ p2md->pod.count += 1 << order;
+ break;
+ case 0:
+ list_add_tail(&page->list, &p2md->pod.single); /* lock:
page_alloc */
+ p2md->pod.count += 1 ;
+ break;
+ default:
+ BUG();
+ }
+
+ spin_unlock(&d->page_alloc_lock);
+
+ return 0;
+}
+
+void
+p2m_pod_empty_cache(struct domain *d)
+{
+ struct p2m_domain *p2md = d->arch.p2m;
+ struct list_head *q, *p;
+
+ spin_lock(&d->page_alloc_lock);
+
+ list_for_each_safe(p, q, &p2md->pod.super) /* lock: page_alloc */
+ {
+ int i;
+ struct page_info *page;
+
+ list_del(p);
+
+ page = list_entry(p, struct page_info, list);
+
+ for ( i = 0 ; i < (1 << 9) ; i++ )
+ {
+ BUG_ON(page_get_owner(page + i) != d);
+ list_add_tail(&page[i].list, &d->page_list);
+ }
+
+ p2md->pod.count -= 1<<9;
+ }
+
+ list_for_each_safe(p, q, &p2md->pod.single)
+ {
+ struct page_info *page;
+
+ list_del(p);
+
+ page = list_entry(p, struct page_info, list);
+
+ BUG_ON(page_get_owner(page) != d);
+ list_add_tail(&page->list, &d->page_list);
+
+ p2md->pod.count -= 1;
+ }
+
+ BUG_ON(p2md->pod.count != 0);
+
+ spin_unlock(&d->page_alloc_lock);
+}
+
+void
+p2m_pod_dump_data(struct domain *d)
+{
+ struct p2m_domain *p2md = d->arch.p2m;
+
+ printk(" PoD entries=%d cachesize=%d\n",
+ p2md->pod.entry_count, p2md->pod.count);
+}
+
+static int
+p2m_pod_demand_populate(struct domain *d, unsigned long gfn,
+ mfn_t table_mfn,
+ l1_pgentry_t *p2m_entry,
+ unsigned int order,
+ p2m_query_t q)
+{
+ struct page_info *p = NULL; /* Compiler warnings */
+ unsigned long gfn_aligned;
+ mfn_t mfn;
+ l1_pgentry_t entry_content = l1e_empty();
+ struct p2m_domain *p2md = d->arch.p2m;
+ int i;
+
+ /* We need to grab the p2m lock here and re-check the entry to make
+ * sure that someone else hasn''t populated it for us, then hold it
+ * until we''re done. */
+ p2m_lock(p2md);
+ audit_p2m(d);
+
+ /* Check to make sure this is still PoD */
+ if ( p2m_flags_to_type(l1e_get_flags(*p2m_entry)) !p2m_populate_on_demand )
+ {
+ p2m_unlock(p2md);
+ return 0;
+ }
+
+ spin_lock(&d->page_alloc_lock);
+
+ if ( p2md->pod.count == 0 )
+ goto out_of_memory;
+
+ /* FIXME -- use single pages / splinter superpages if need be */
+ switch ( order )
+ {
+ case 9:
+ BUG_ON( list_empty(&p2md->pod.super) );
+ p = list_entry(p2md->pod.super.next, struct page_info, list);
+ p2md->pod.count -= 1 << order; /* Lock: page_alloc */
+ break;
+ case 0:
+ BUG_ON( list_empty(&p2md->pod.single) );
+ p = list_entry(p2md->pod.single.next, struct page_info, list);
+ p2md->pod.count -= 1;
+ break;
+ default:
+ BUG();
+ }
+
+ list_del(&p->list);
+
+ mfn = page_to_mfn(p);
+
+ BUG_ON((mfn_x(mfn) & ((1 << order)-1)) != 0);
+
+ /* Put the pages back on the domain page_list */
+ for ( i = 0 ; i < (1 << order) ; i++ )
+ {
+ BUG_ON(page_get_owner(p + i) != d);
+ list_add_tail(&p[i].list, &d->page_list);
+ }
+
+ spin_unlock(&d->page_alloc_lock);
+
+ /* Fill in the entry in the p2m */
+ switch ( order )
+ {
+ case 9:
+ {
+ l2_pgentry_t l2e_content;
+
+ l2e_content = l2e_from_pfn(mfn_x(mfn),
+ p2m_type_to_flags(p2m_ram_rw) | _PAGE_PSE);
+
+ entry_content.l1 = l2e_content.l2;
+ }
+ break;
+ case 0:
+ entry_content = l1e_from_pfn(mfn_x(mfn),
+ p2m_type_to_flags(p2m_ram_rw));
+ break;
+
+ }
+
+ gfn_aligned = (gfn >> order) << order;
+
+ paging_write_p2m_entry(d, gfn_aligned, p2m_entry, table_mfn,
+ entry_content, (order==9)?2:1);
+
+ for( i = 0 ; i < (1UL << order) ; i++ )
+ set_gpfn_from_mfn(mfn_x(mfn) + i, gfn_aligned + i);
+
+ p2md->pod.entry_count -= (1 << order); /* Lock: p2m */
+ BUG_ON(p2md->pod.entry_count < 0);
+ audit_p2m(d);
+ p2m_unlock(p2md);
+
+ return 0;
+out_of_memory:
+ spin_unlock(&d->page_alloc_lock);
+ audit_p2m(d);
+ p2m_unlock(p2md);
+ printk("%s: Out of populate-on-demand memory!\n", __func__);
+ domain_crash(d);
+ return -1;
}
// Returns 0 on error (out of memory)
@@ -303,6 +541,7 @@
L2_PAGETABLE_ENTRIES);
ASSERT(p2m_entry);
+ /* FIXME: Deal with 4k replaced by 2meg pages */
if ( (l1e_get_flags(*p2m_entry) & _PAGE_PRESENT) &&
!(l1e_get_flags(*p2m_entry) & _PAGE_PSE) )
{
@@ -311,7 +550,7 @@
goto out;
}
- if ( mfn_valid(mfn) )
+ if ( mfn_valid(mfn) || p2m_is_magic(p2mt) )
l2e_content = l2e_from_pfn(mfn_x(mfn),
p2m_type_to_flags(p2mt) | _PAGE_PSE);
else
@@ -403,8 +642,21 @@
l2e = map_domain_page(mfn_x(mfn));
l2e += l2_table_offset(addr);
+
+pod_retry_l2:
if ( (l2e_get_flags(*l2e) & _PAGE_PRESENT) == 0 )
{
+ /* PoD: Try to populate a 2-meg chunk */
+ if ( p2m_flags_to_type(l2e_get_flags(*l2e)) == p2m_populate_on_demand )
+ {
+ if ( q != p2m_query ) {
+ if( !p2m_pod_demand_populate(d, gfn, mfn,
+ (l1_pgentry_t *)l2e, 9, q) )
+ goto pod_retry_l2;
+ } else
+ *t = p2m_populate_on_demand;
+ }
+
unmap_domain_page(l2e);
return _mfn(INVALID_MFN);
}
@@ -423,8 +675,20 @@
l1e = map_domain_page(mfn_x(mfn));
l1e += l1_table_offset(addr);
+pod_retry_l1:
if ( (l1e_get_flags(*l1e) & _PAGE_PRESENT) == 0 )
{
+ /* PoD: Try to populate */
+ if ( p2m_flags_to_type(l1e_get_flags(*l1e)) == p2m_populate_on_demand )
+ {
+ if ( q != p2m_query ) {
+ if( !p2m_pod_demand_populate(d, gfn, mfn,
+ (l1_pgentry_t *)l1e, 0, q) )
+ goto pod_retry_l1;
+ } else
+ *t = p2m_populate_on_demand;
+ }
+
unmap_domain_page(l1e);
return _mfn(INVALID_MFN);
}
@@ -450,48 +714,114 @@
if ( gfn <= current->domain->arch.p2m->max_mapped_pfn )
{
- l1_pgentry_t l1e = l1e_empty();
+ l1_pgentry_t l1e = l1e_empty(), *p2m_entry;
l2_pgentry_t l2e = l2e_empty();
int ret;
ASSERT(gfn < (RO_MPT_VIRT_END - RO_MPT_VIRT_START)
/ sizeof(l1_pgentry_t));
+ /*
+ * Read & process L2
+ */
+ p2m_entry = &__linear_l1_table[l1_linear_offset(RO_MPT_VIRT_START)
+ + l2_linear_offset(addr)];
+
+ pod_retry_l2:
ret = __copy_from_user(&l2e,
-
&__linear_l1_table[l1_linear_offset(RO_MPT_VIRT_START) +
l2_linear_offset(addr)],
+ p2m_entry,
sizeof(l2e));
+ if ( ret != 0
+ || !(l2e_get_flags(l2e) & _PAGE_PRESENT) )
+ {
+ if( (l2e_get_flags(l2e) & _PAGE_PSE)
+ && ( p2m_flags_to_type(l2e_get_flags(l2e))
+ == p2m_populate_on_demand ) )
+ {
+ /* The read has succeeded, so we know that the mapping
+ * exits at this point. */
+ if ( q != p2m_query )
+ {
+ if( !p2m_pod_demand_populate(current->domain, gfn, mfn,
+ p2m_entry, 9, q) )
+ goto pod_retry_l2;
+
+ /* Allocate failed. */
+ p2mt = p2m_invalid;
+ printk("%s: Allocate failed!\n", __func__);
+ goto out;
+ }
+ else
+ {
+ p2mt = p2m_populate_on_demand;
+ goto out;
+ }
+ }
+
+ goto pod_retry_l1;
+ }
- if ( (ret == 0) && (l2e_get_flags(l2e) & _PAGE_PRESENT)
&&
- (l2e_get_flags(l2e) & _PAGE_PSE) )
+ if (l2e_get_flags(l2e) & _PAGE_PSE)
{
p2mt = p2m_flags_to_type(l2e_get_flags(l2e));
ASSERT(l2e_get_pfn(l2e) != INVALID_MFN || !p2m_is_ram(p2mt));
+
if ( p2m_is_valid(p2mt) )
mfn = _mfn(l2e_get_pfn(l2e) + l1_table_offset(addr));
else
p2mt = p2m_mmio_dm;
+
+ goto out;
}
- else
- {
-
- /* Need to __copy_from_user because the p2m is sparse and this
- * part might not exist */
- ret = __copy_from_user(&l1e,
- &phys_to_machine_mapping[gfn],
- sizeof(l1e));
+
+ /*
+ * Read and process L1
+ */
+
+ /* Need to __copy_from_user because the p2m is sparse and this
+ * part might not exist */
+ pod_retry_l1:
+ p2m_entry = &phys_to_machine_mapping[gfn];
+
+ ret = __copy_from_user(&l1e,
+ p2m_entry,
+ sizeof(l1e));
- if ( ret == 0 ) {
- p2mt = p2m_flags_to_type(l1e_get_flags(l1e));
- ASSERT(l1e_get_pfn(l1e) != INVALID_MFN || !p2m_is_ram(p2mt));
- if ( p2m_is_valid(p2mt) )
- mfn = _mfn(l1e_get_pfn(l1e));
- else
- /* XXX see above */
- p2mt = p2m_mmio_dm;
+ if ( ret == 0 ) {
+ p2mt = p2m_flags_to_type(l1e_get_flags(l1e));
+ ASSERT(l1e_get_pfn(l1e) != INVALID_MFN || !p2m_is_ram(p2mt));
+
+ if ( p2m_flags_to_type(l1e_get_flags(l1e))
+ == p2m_populate_on_demand )
+ {
+ /* The read has succeeded, so we know that the mapping
+ * exits at this point. */
+ if ( q != p2m_query )
+ {
+ if( !p2m_pod_demand_populate(current->domain, gfn, mfn,
+ (l1_pgentry_t *)p2m_entry, 0,
+ q) )
+ goto pod_retry_l1;
+
+ /* Allocate failed. */
+ p2mt = p2m_invalid;
+ goto out;
+ }
+ else
+ {
+ p2mt = p2m_populate_on_demand;
+ goto out;
+ }
}
+
+ if ( p2m_is_valid(p2mt) )
+ mfn = _mfn(l1e_get_pfn(l1e));
+ else
+ /* XXX see above */
+ p2mt = p2m_mmio_dm;
}
}
-
+out:
*t = p2mt;
return mfn;
}
@@ -510,6 +840,8 @@
memset(p2m, 0, sizeof(*p2m));
p2m_lock_init(p2m);
INIT_LIST_HEAD(&p2m->pages);
+ INIT_LIST_HEAD(&p2m->pod.super);
+ INIT_LIST_HEAD(&p2m->pod.single);
p2m->set_entry = p2m_set_entry;
p2m->get_entry = p2m_gfn_to_mfn;
@@ -680,6 +1012,7 @@
struct page_info *page;
struct domain *od;
unsigned long mfn, gfn, m2pfn, lp2mfn = 0;
+ int entry_count = 0;
mfn_t p2mfn;
unsigned long orphans_d = 0, orphans_i = 0, mpbad = 0, pmbad = 0;
int test_linear;
@@ -809,6 +1142,10 @@
{
if ( !(l2e_get_flags(l2e[i2]) & _PAGE_PRESENT) )
{
+ if ( (l2e_get_flags(l2e[i2]) & _PAGE_PSE)
+ && (
p2m_flags_to_type(l2e_get_flags(l2e[i2]))
+ == p2m_populate_on_demand ) )
+ entry_count+=(1<<9);
gfn += 1 << (L2_PAGETABLE_SHIFT - PAGE_SHIFT);
continue;
}
@@ -839,13 +1176,20 @@
for ( i1 = 0; i1 < L1_PAGETABLE_ENTRIES; i1++, gfn++ )
{
if ( !(l1e_get_flags(l1e[i1]) & _PAGE_PRESENT) )
+ {
+ if ( p2m_flags_to_type(l1e_get_flags(l1e[i1]))
+ == p2m_populate_on_demand )
+ entry_count++;
continue;
+ }
mfn = l1e_get_pfn(l1e[i1]);
ASSERT(mfn_valid(_mfn(mfn)));
m2pfn = get_gpfn_from_mfn(mfn);
if ( m2pfn != gfn )
{
pmbad++;
+ printk("mismatch: gfn %#lx -> mfn
%#lx"
+ " -> gfn %#lx\n", gfn, mfn,
m2pfn);
P2M_PRINTK("mismatch: gfn %#lx -> mfn
%#lx"
" -> gfn %#lx\n", gfn, mfn,
m2pfn);
BUG();
@@ -868,6 +1212,15 @@
}
+ if ( entry_count != d->arch.p2m->pod.entry_count )
+ {
+ printk("%s: refcounted entry count %d, audit count %d!\n",
+ __func__,
+ d->arch.p2m->pod.entry_count,
+ entry_count);
+ BUG();
+ }
+
//P2M_PRINTK("p2m audit complete\n");
//if ( orphans_i | orphans_d | mpbad | pmbad )
// P2M_PRINTK("p2m audit found %lu orphans (%lu inval %lu
debug)\n",
@@ -876,8 +1229,6 @@
P2M_PRINTK("p2m audit found %lu odd p2m, %lu bad m2p
entries\n",
pmbad, mpbad);
}
-#else
-#define audit_p2m(_d) do { (void)(_d); } while(0)
#endif /* P2M_AUDIT */
@@ -915,6 +1266,77 @@
}
int
+guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn,
+ unsigned int order)
+{
+ struct p2m_domain *p2md = d->arch.p2m;
+ unsigned long i;
+ p2m_type_t ot;
+ mfn_t omfn;
+ int pod_count = 0;
+ int rc = 0;
+
+ BUG_ON(!paging_mode_translate(d));
+
+#if CONFIG_PAGING_LEVELS == 3
+ /*
+ * 32bit PAE nested paging does not support over 4GB guest due to
+ * hardware translation limit. This limitation is checked by comparing
+ * gfn with 0xfffffUL.
+ */
+ if ( paging_mode_hap(d) && (gfn > 0xfffffUL) )
+ {
+ if ( !test_and_set_bool(d->arch.hvm_domain.svm.npt_4gb_warning) )
+ dprintk(XENLOG_WARNING, "Dom%d failed to populate memory
beyond"
+ " 4GB: specify ''hap=0'' domain config
option.\n",
+ d->domain_id);
+ return -EINVAL;
+ }
+#endif
+
+ p2m_lock(p2md);
+ audit_p2m(d);
+
+ P2M_DEBUG("adding gfn=%#lx mfn=%#lx\n", gfn, mfn);
+
+ /* Make sure all gpfns are unused */
+ for ( i = 0; i < (1UL << order); i++ )
+ {
+ omfn = gfn_to_mfn_query(d, gfn + i, &ot);
+ if ( p2m_is_ram(ot) )
+ {
+ printk("%s: gfn_to_mfn returned type %d!\n",
+ __func__, ot);
+ rc = -EBUSY;
+ goto out;
+ }
+ else if ( ot == p2m_populate_on_demand )
+ {
+ /* Count how man PoD entries we''ll be replacing if
successful */
+ pod_count++;
+ }
+ }
+
+ /* Now, actually do the two-way mapping */
+ if ( !set_p2m_entry(d, gfn, _mfn(POPULATE_ON_DEMAND_MFN), order,
+ p2m_populate_on_demand) )
+ rc = -EINVAL;
+ else
+ {
+ p2md->pod.entry_count += 1 << order; /* Lock: p2m */
+ p2md->pod.entry_count -= pod_count;
+ BUG_ON(p2md->pod.entry_count < 0);
+ }
+
+ audit_p2m(d);
+ p2m_unlock(p2md);
+
+out:
+ return rc;
+
+}
+
+int
guest_physmap_add_entry(struct domain *d, unsigned long gfn,
unsigned long mfn, unsigned int page_order,
p2m_type_t t)
@@ -922,6 +1344,7 @@
unsigned long i, ogfn;
p2m_type_t ot;
mfn_t omfn;
+ int pod_count = 0;
int rc = 0;
if ( !paging_mode_translate(d) )
@@ -969,6 +1392,11 @@
ASSERT(mfn_valid(omfn));
set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY);
}
+ else if ( ot == p2m_populate_on_demand )
+ {
+ /* Count how man PoD entries we''ll be replacing if
successful */
+ pod_count++;
+ }
}
/* Then, look for m->p mappings for this range and deal with them */
@@ -1015,6 +1443,11 @@
if ( !set_p2m_entry(d, gfn, _mfn(INVALID_MFN), page_order,
p2m_invalid) )
rc = -EINVAL;
+ else
+ {
+ d->arch.p2m->pod.entry_count -= pod_count; /* Lock: p2m */
+ BUG_ON(d->arch.p2m->pod.entry_count < 0);
+ }
}
audit_p2m(d);
diff -r e61e4075a710 xen/arch/x86/mm/paging.c
--- a/xen/arch/x86/mm/paging.c Wed Dec 17 12:59:51 2008 +0000
+++ b/xen/arch/x86/mm/paging.c Fri Dec 19 17:51:53 2008 +0000
@@ -585,6 +585,9 @@
/* clean up log dirty resources. */
paging_log_dirty_teardown(d);
+
+ /* Move populate-on-demand cache back to domain_list for destruction */
+ p2m_pod_empty_cache(d);
}
/* Call once all of the references to the domain have gone away */
diff -r e61e4075a710 xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c Wed Dec 17 12:59:51 2008 +0000
+++ b/xen/arch/x86/mm/shadow/multi.c Fri Dec 19 17:51:53 2008 +0000
@@ -2173,7 +2173,7 @@
mfn_t gl3mfn = gfn_to_mfn_query(d, gl3gfn, &p2mt);
if ( p2m_is_ram(p2mt) )
sl3mfn = get_shadow_status(v, gl3mfn, SH_type_l3_shadow);
- else
+ else if ( p2mt != p2m_populate_on_demand )
result |= SHADOW_SET_ERROR;
#if (SHADOW_OPTIMIZATIONS && SHOPT_OUT_OF_SYNC )
@@ -2230,7 +2230,7 @@
mfn_t gl2mfn = gfn_to_mfn_query(v->domain, gl2gfn, &p2mt);
if ( p2m_is_ram(p2mt) )
sl2mfn = get_shadow_status(v, gl2mfn, SH_type_l2_shadow);
- else
+ else if ( p2mt != p2m_populate_on_demand )
result |= SHADOW_SET_ERROR;
#if (SHADOW_OPTIMIZATIONS && SHOPT_OUT_OF_SYNC )
@@ -2278,8 +2278,8 @@
{
mfn_t gl1mfn = gfn_to_mfn_query(v->domain, gl1gfn, &p2mt);
if ( p2m_is_ram(p2mt) )
- sl1mfn = get_shadow_status(v, gl1mfn, SH_type_l1_shadow);
- else
+ sl1mfn = get_shadow_status(v, gl1mfn, SH_type_l1_shadow);
+ else if ( p2mt != p2m_populate_on_demand )
result |= SHADOW_SET_ERROR;
}
}
diff -r e61e4075a710 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Wed Dec 17 12:59:51 2008 +0000
+++ b/xen/include/asm-x86/p2m.h Fri Dec 19 17:51:53 2008 +0000
@@ -64,6 +64,7 @@
p2m_ram_ro = 3, /* Read-only; writes are silently dropped */
p2m_mmio_dm = 4, /* Reads and write go to the device model */
p2m_mmio_direct = 5, /* Read/write mapping of genuine MMIO area */
+ p2m_populate_on_demand = 6, /* Place-holder for empty memory */
} p2m_type_t;
typedef enum {
@@ -88,11 +89,19 @@
#define P2M_RO_TYPES (p2m_to_mask(p2m_ram_logdirty) \
| p2m_to_mask(p2m_ram_ro))
+#define P2M_MAGIC_TYPES (p2m_to_mask(p2m_populate_on_demand))
+
/* Useful predicates */
#define p2m_is_ram(_t) (p2m_to_mask(_t) & P2M_RAM_TYPES)
#define p2m_is_mmio(_t) (p2m_to_mask(_t) & P2M_MMIO_TYPES)
#define p2m_is_readonly(_t) (p2m_to_mask(_t) & P2M_RO_TYPES)
+#define p2m_is_magic(_t) (p2m_to_mask(_t) & P2M_MAGIC_TYPES)
#define p2m_is_valid(_t) (p2m_to_mask(_t) & (P2M_RAM_TYPES |
P2M_MMIO_TYPES))
+
+/* Populate-on-demand */
+#define POPULATE_ON_DEMAND_MFN (1<<9)
+#define POD_PAGE_ORDER 9
+
struct p2m_domain {
/* Lock that protects updates to the p2m */
@@ -122,6 +131,28 @@
/* Highest guest frame that''s ever been mapped in the p2m */
unsigned long max_mapped_pfn;
+
+ /* Populate-on-demand variables
+ * NB on locking. {super,single,count} are
+ * covered by d->page_alloc_lock, since they''re almost always
used in
+ * conjunction with that functionality. {entry_count} is covered by
+ * the domain p2m lock, since it''s almost always used in
conjunction
+ * with changing the p2m tables.
+ *
+ * At this point, both locks are held in two places. In both,
+ * the order is [p2m,page_alloc]:
+ * + p2m_pod_decrease_reservation() calls p2m_pod_cache_add(),
+ * which grabs page_alloc
+ * + p2m_pod_demand_populate() grabs both; the p2m lock to avoid
+ * double-demand-populating of pages, the page_alloc lock to
+ * protect moving stuff from the PoD cache to the domain page list.
+ */
+ struct {
+ struct list_head super, /* List of superpages */
+ single; /* Non-super lists */
+ int count, /* # of pages in cache lists */
+ entry_count; /* # of pages in p2m marked pod */
+ } pod;
};
/* Extract the type from the PTE flags that store it */
@@ -220,10 +251,21 @@
void p2m_teardown(struct domain *d);
void p2m_final_teardown(struct domain *d);
+/* Dump PoD information about the domain */
+void p2m_pod_dump_data(struct domain *d);
+
+/* Move all pages from the populate-on-demand cache to the domain page_list
+ * (usually in preparation for domain destruction) */
+void p2m_pod_empty_cache(struct domain *d);
+
/* Add a page to a domain''s p2m table */
int guest_physmap_add_entry(struct domain *d, unsigned long gfn,
unsigned long mfn, unsigned int page_order,
p2m_type_t t);
+
+/* Set a p2m range as populate-on-demand */
+int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn,
+ unsigned int order);
/* Untyped version for RAM only, for compatibility
*
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