Roger Pau Monne
2013-Jul-31 16:05 UTC
[PATCH RFC] xen/grant_table: introduce GNTTABOP_unmap_and_duplicate
GNTTABOP_unmap_and_replace has two issues:
- it unconditionally replaces the mapping passed in new_addr with 0;
- it doesn't support GNTMAP_contains_pte mappings on x86, returning a
general error instead of some form of ENOSYS.
Introduce a new operation called GNTTABOP_unmap_and_duplicate that
behaves like GNTTABOP_unmap_and_replace without zeroing the mapping
passed in new_addr. Also return GNTST_enosys instead of
GNTST_general_error if GNTMAP_contains_pte is specified.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Tim Deegan <tim@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
---
xen/arch/arm/mm.c | 2 +-
xen/arch/x86/mm.c | 36 ++++++++++++----
xen/common/compat/grant_table.c | 8 ++++
xen/common/grant_table.c | 83 ++++++++++++++++++++++++++++++++++++-
xen/include/asm-arm/grant_table.h | 2 +-
xen/include/asm-x86/grant_table.h | 3 +-
xen/include/public/grant_table.h | 23 ++++++++++
xen/include/xlat.lst | 1 +
8 files changed, 145 insertions(+), 13 deletions(-)
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index d1290cd..6045c90 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1122,7 +1122,7 @@ int create_grant_host_mapping(unsigned long addr, unsigned
long frame,
}
int replace_grant_host_mapping(unsigned long addr, unsigned long mfn,
- unsigned long new_addr, unsigned int flags)
+ unsigned long new_addr, unsigned int flags, bool_t zero_new_addr)
{
unsigned long gfn = (unsigned long)(addr >> PAGE_SHIFT);
struct domain *d = current->domain;
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index c00841c..4ff0025 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4048,7 +4048,8 @@ static int replace_grant_p2m_mapping(
}
int replace_grant_host_mapping(
- uint64_t addr, unsigned long frame, uint64_t new_addr, unsigned int flags)
+ uint64_t addr, unsigned long frame, uint64_t new_addr, unsigned int flags,
+ bool_t zero_new_addr)
{
struct vcpu *curr = current;
l1_pgentry_t *pl1e, ol1e;
@@ -4065,7 +4066,7 @@ int replace_grant_host_mapping(
return destroy_grant_pte_mapping(addr, frame, curr->domain);
MEM_LOG("Unsupported grant table operation");
- return GNTST_general_error;
+ return GNTST_enosys;
}
if ( !new_addr )
@@ -4103,14 +4104,31 @@ int replace_grant_host_mapping(
ol1e = *pl1e;
- if ( unlikely(!UPDATE_ENTRY(l1, pl1e, ol1e, l1e_empty(),
- gl1mfn, curr, 0)) )
+ if ( zero_new_addr )
{
- page_unlock(l1pg);
- put_page(l1pg);
- MEM_LOG("Cannot delete PTE entry at %p", (unsigned long
*)pl1e);
- guest_unmap_l1e(curr, pl1e);
- return GNTST_general_error;
+ if ( unlikely(!UPDATE_ENTRY(l1, pl1e, ol1e, l1e_empty(),
+ gl1mfn, curr, 0)) )
+ {
+ page_unlock(l1pg);
+ put_page(l1pg);
+ MEM_LOG("Cannot delete PTE entry at %p", (unsigned long
*)pl1e);
+ guest_unmap_l1e(curr, pl1e);
+ return GNTST_general_error;
+ }
+ }
+ else
+ {
+ /* Increase refcount */
+ if ( unlikely(!get_page_and_type(l1e_get_page(ol1e), curr->domain,
+ PGT_writable_page)) )
+ {
+ page_unlock(l1pg);
+ put_page(l1pg);
+ guest_unmap_l1e(curr, pl1e);
+ MEM_LOG("Cannot increase refcount of frame at %"PRI_mfn,
+ page_to_mfn(l1e_get_page(ol1e)));
+ return GNTST_general_error;
+ }
}
page_unlock(l1pg);
diff --git a/xen/common/compat/grant_table.c b/xen/common/compat/grant_table.c
index 7ebbbc1..8ab5e78 100644
--- a/xen/common/compat/grant_table.c
+++ b/xen/common/compat/grant_table.c
@@ -51,6 +51,10 @@ CHECK_gnttab_get_version;
CHECK_gnttab_swap_grant_ref;
#undef xen_gnttab_swap_grant_ref
+#define xen_gnttab_unmap_and_duplicate gnttab_unmap_and_duplicate
+CHECK_gnttab_unmap_and_duplicate;
+#undef xen_gnttab_unmap_and_duplicate
+
int compat_grant_table_op(unsigned int cmd,
XEN_GUEST_HANDLE_PARAM(void) cmp_uop,
unsigned int count)
@@ -106,6 +110,10 @@ int compat_grant_table_op(unsigned int cmd,
CASE(swap_grant_ref);
#endif
+#ifndef CHECK_gnttab_unmap_and_duplicate
+ CASE(unmap_and_duplicate);
+#endif
+
#undef CASE
default:
return do_grant_table_op(cmd, cmp_uop, count);
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index eb50288..de154ff 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -70,6 +70,7 @@ struct gnttab_unmap_common {
uint64_t dev_bus_addr;
uint64_t new_addr;
grant_handle_t handle;
+ bool_t zero_new_addr;
/* Return */
int16_t status;
@@ -921,7 +922,8 @@ __gnttab_unmap_common(
{
if ( (rc = replace_grant_host_mapping(op->host_addr,
op->frame, op->new_addr,
- op->flags)) < 0 )
+ op->flags,
+ op->zero_new_addr)) < 0 )
goto unmap_out;
ASSERT(act->pin & (GNTPIN_hstw_mask | GNTPIN_hstr_mask));
@@ -1130,6 +1132,7 @@ __gnttab_unmap_and_replace(
common->host_addr = op->host_addr;
common->new_addr = op->new_addr;
common->handle = op->handle;
+ common->zero_new_addr = 1;
/* Intialise these in case common contains old state */
common->dev_bus_addr = 0;
@@ -1185,6 +1188,70 @@ fault:
return -EFAULT;
}
+static void
+__gnttab_unmap_and_duplicate(
+ struct gnttab_unmap_and_duplicate *op,
+ struct gnttab_unmap_common *common)
+{
+ common->host_addr = op->host_addr;
+ common->new_addr = op->new_addr;
+ common->handle = op->handle;
+ common->zero_new_addr = 0;
+
+ /* Intialise these in case common contains old state */
+ common->dev_bus_addr = 0;
+ common->rd = NULL;
+
+ __gnttab_unmap_common(common);
+ op->status = common->status;
+}
+
+static long
+gnttab_unmap_and_duplicate(
+ XEN_GUEST_HANDLE_PARAM(gnttab_unmap_and_duplicate_t) uop, unsigned int
count)
+{
+ int i, c, partial_done, done = 0;
+ struct gnttab_unmap_and_duplicate op;
+ struct gnttab_unmap_common common[GNTTAB_UNMAP_BATCH_SIZE];
+
+ while ( count != 0 )
+ {
+ c = min(count, (unsigned int)GNTTAB_UNMAP_BATCH_SIZE);
+ partial_done = 0;
+
+ for ( i = 0; i < c; i++ )
+ {
+ if ( unlikely(__copy_from_guest(&op, uop, 1)) )
+ goto fault;
+ __gnttab_unmap_and_duplicate(&op, &(common[i]));
+ ++partial_done;
+ if ( unlikely(__copy_field_to_guest(uop, &op, status)) )
+ goto fault;
+ guest_handle_add_offset(uop, 1);
+ }
+
+ flush_tlb_mask(current->domain->domain_dirty_cpumask);
+
+ for ( i = 0; i < partial_done; i++ )
+ __gnttab_unmap_common_complete(&(common[i]));
+
+ count -= c;
+ done += c;
+
+ if (count && hypercall_preempt_check())
+ return done;
+ }
+
+ return 0;
+
+fault:
+ flush_tlb_mask(current->domain->domain_dirty_cpumask);
+
+ for ( i = 0; i < partial_done; i++ )
+ __gnttab_unmap_common_complete(&(common[i]));
+ return -EFAULT;
+}
+
static int
gnttab_populate_status_frames(struct domain *d, struct grant_table *gt,
unsigned int req_nr_frames)
@@ -2553,6 +2620,20 @@ do_grant_table_op(
}
break;
}
+ case GNTTABOP_unmap_and_duplicate:
+ {
+ XEN_GUEST_HANDLE_PARAM(gnttab_unmap_and_duplicate_t) unmap +
guest_handle_cast(uop, gnttab_unmap_and_duplicate_t);
+ if ( unlikely(!guest_handle_okay(unmap, count)) )
+ goto out;
+ rc = gnttab_unmap_and_duplicate(unmap, count);
+ if ( rc > 0 )
+ {
+ guest_handle_add_offset(unmap, rc);
+ uop = guest_handle_cast(unmap, void);
+ }
+ break;
+ }
default:
rc = -ENOSYS;
break;
diff --git a/xen/include/asm-arm/grant_table.h
b/xen/include/asm-arm/grant_table.h
index 6e0cc59..0410355 100644
--- a/xen/include/asm-arm/grant_table.h
+++ b/xen/include/asm-arm/grant_table.h
@@ -12,7 +12,7 @@ int create_grant_host_mapping(unsigned long gpaddr,
cache_flags);
#define gnttab_host_mapping_get_page_type(op, d, rd) (0)
int replace_grant_host_mapping(unsigned long gpaddr, unsigned long mfn,
- unsigned long new_gpaddr, unsigned int flags);
+ unsigned long new_gpaddr, unsigned int flags, bool_t zero_new_addr);
void gnttab_mark_dirty(struct domain *d, unsigned long l);
#define gnttab_create_status_page(d, t, i) do {} while (0)
#define gnttab_status_gmfn(d, t, i) (0)
diff --git a/xen/include/asm-x86/grant_table.h
b/xen/include/asm-x86/grant_table.h
index 3013869..e985968 100644
--- a/xen/include/asm-x86/grant_table.h
+++ b/xen/include/asm-x86/grant_table.h
@@ -16,7 +16,8 @@
int create_grant_host_mapping(uint64_t addr, unsigned long frame,
unsigned int flags, unsigned int cache_flags);
int replace_grant_host_mapping(
- uint64_t addr, unsigned long frame, uint64_t new_addr, unsigned int flags);
+ uint64_t addr, unsigned long frame, uint64_t new_addr, unsigned int flags,
+ bool_t zero_new_addr);
#define gnttab_create_shared_page(d, t, i) \
do { \
diff --git a/xen/include/public/grant_table.h b/xen/include/public/grant_table.h
index b8a3d6c..a4ad98d 100644
--- a/xen/include/public/grant_table.h
+++ b/xen/include/public/grant_table.h
@@ -309,6 +309,7 @@ typedef uint16_t grant_status_t;
#define GNTTABOP_get_status_frames 9
#define GNTTABOP_get_version 10
#define GNTTABOP_swap_grant_ref 11
+#define GNTTABOP_unmap_and_duplicate 12
#endif /* __XEN_INTERFACE_VERSION__ */
/* ` } */
@@ -574,6 +575,27 @@ struct gnttab_swap_grant_ref {
typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
+/*
+ * GNTTABOP_unmap_and_duplicate: Destroy one or more grant-reference mappings
+ * tracked by <handle> but atomically replace the page table entry with
one
+ * pointing to the machine address under <new_addr>.
+ * NOTES:
+ * 1. The call may fail in an undefined manner if either mapping is not
+ * tracked by <handle>.
+ * 2. After executing a batch of unmaps, it is guaranteed that no stale
+ * mappings will remain in the device or host TLBs.
+ */
+struct gnttab_unmap_and_duplicate {
+ /* IN parameters. */
+ uint64_t host_addr;
+ uint64_t new_addr;
+ grant_handle_t handle;
+ /* OUT parameters. */
+ int16_t status; /* => enum grant_status */
+};
+typedef struct gnttab_unmap_and_duplicate gnttab_unmap_and_duplicate_t;
+DEFINE_XEN_GUEST_HANDLE(gnttab_unmap_and_duplicate_t);
+
#endif /* __XEN_INTERFACE_VERSION__ */
/*
@@ -631,6 +653,7 @@ DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
#define GNTST_bad_copy_arg (-10) /* copy arguments cross page boundary. */
#define GNTST_address_too_big (-11) /* transfer page address too large. */
#define GNTST_eagain (-12) /* Operation not done; try again. */
+#define GNTST_enosys (-13) /* Operation not implemented. */
/* ` } */
#define GNTTABOP_error_msgs { \
diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
index d832110..2ad8d86 100644
--- a/xen/include/xlat.lst
+++ b/xen/include/xlat.lst
@@ -51,6 +51,7 @@
? grant_entry_header grant_table.h
? grant_entry_v2 grant_table.h
? gnttab_swap_grant_ref grant_table.h
+? gnttab_unmap_and_duplicate grant_table.h
? kexec_exec kexec.h
! kexec_image kexec.h
! kexec_range kexec.h
--
1.7.7.5 (Apple Git-26)
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
Roger Pau Monné
2013-Aug-26 13:51 UTC
Re: [PATCH RFC] xen/grant_table: introduce GNTTABOP_unmap_and_duplicate
On 31/07/13 18:05, Roger Pau Monne wrote:> GNTTABOP_unmap_and_replace has two issues: > - it unconditionally replaces the mapping passed in new_addr with 0; > - it doesn't support GNTMAP_contains_pte mappings on x86, returning a > general error instead of some form of ENOSYS. > > Introduce a new operation called GNTTABOP_unmap_and_duplicate that > behaves like GNTTABOP_unmap_and_replace without zeroing the mapping > passed in new_addr. Also return GNTST_enosys instead of > GNTST_general_error if GNTMAP_contains_pte is specified. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> > Cc: Tim Deegan <tim@xen.org> > Cc: Jan Beulich <jbeulich@suse.com> > Cc: Keir Fraser <keir@xen.org>Any comments on this one or should I just drop the RFC and resend? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel