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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] x86: Clean up get_page_from_l1e() to correctly distinguish between
# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1244036434 -3600
# Node ID c4b048ce6a4b61111382ce37c6afaeed0234282e
# Parent 07cf79dfb59c8a8eb03b7da9fdf9860f3da8e5cc
x86: Clean up get_page_from_l1e() to correctly distinguish between
owner-of-pte and owner-of-data-page in all cases.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/mm.c | 81 ++++++++++++++++++++---------------------
xen/arch/x86/mm/shadow/multi.c | 4 +-
xen/include/asm-x86/mm.h | 5 +-
3 files changed, 46 insertions(+), 44 deletions(-)
diff -r 07cf79dfb59c -r c4b048ce6a4b xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Wed Jun 03 12:59:44 2009 +0100
+++ b/xen/arch/x86/mm.c Wed Jun 03 14:40:34 2009 +0100
@@ -726,66 +726,69 @@ static void update_xen_mappings(unsigned
#endif
}
-
int
get_page_from_l1e(
- l1_pgentry_t l1e, struct domain *d)
+ l1_pgentry_t l1e, struct domain *l1e_owner, struct domain *pg_owner)
{
unsigned long mfn = l1e_get_pfn(l1e);
struct page_info *page = mfn_to_page(mfn);
uint32_t l1f = l1e_get_flags(l1e);
struct vcpu *curr = current;
- struct domain *owner;
+ struct domain *real_pg_owner;
if ( !(l1f & _PAGE_PRESENT) )
return 1;
- if ( unlikely(l1f & l1_disallow_mask(d)) )
- {
- MEM_LOG("Bad L1 flags %x", l1f & l1_disallow_mask(d));
+ if ( unlikely(l1f & l1_disallow_mask(l1e_owner)) )
+ {
+ MEM_LOG("Bad L1 flags %x", l1f & l1_disallow_mask(l1e_owner));
return 0;
}
if ( !mfn_valid(mfn) ||
- (owner = page_get_owner_and_reference(page)) == dom_io )
+ (real_pg_owner = page_get_owner_and_reference(page)) == dom_io )
{
/* Only needed the reference to confirm dom_io ownership. */
if ( mfn_valid(mfn) )
put_page(page);
/* DOMID_IO reverts to caller for privilege checks. */
- if ( d == dom_io )
- d = curr->domain;
-
- if ( !iomem_access_permitted(d, mfn, mfn) )
+ if ( pg_owner == dom_io )
+ pg_owner = curr->domain;
+
+ if ( !iomem_access_permitted(pg_owner, mfn, mfn) )
{
if ( mfn != (PADDR_MASK >> PAGE_SHIFT) ) /* INVALID_MFN? */
MEM_LOG("Non-privileged (%u) attempt to map I/O space %08lx",
- d->domain_id, mfn);
+ pg_owner->domain_id, mfn);
return 0;
}
return 1;
}
- if ( owner == NULL )
+ if ( real_pg_owner == NULL )
goto could_not_pin;
- /*
- * Let privileged domains transfer the right to map their target
- * domain's pages. This is used to allow stub-domain pvfb export to dom0,
- * until pvfb supports granted mappings. At that time this minor hack
- * can go away.
- */
- if ( unlikely(d != owner) && (d != curr->domain) && IS_PRIV_FOR(d, owner) )
- d = owner;
+ if ( unlikely(real_pg_owner != pg_owner) )
+ {
+ /*
+ * Let privileged domains transfer the right to map their target
+ * domain's pages. This is used to allow stub-domain pvfb export to
+ * dom0, until pvfb supports granted mappings. At that time this
+ * minor hack can go away.
+ */
+ if ( (pg_owner == l1e_owner) || !IS_PRIV_FOR(pg_owner, real_pg_owner) )
+ goto could_not_pin;
+ pg_owner = real_pg_owner;
+ }
/* Foreign mappings into guests in shadow external mode don't
* contribute to writeable mapping refcounts. (This allows the
* qemu-dm helper process in dom0 to map the domain's memory without
* messing up the count of "real" writable mappings.) */
if ( (l1f & _PAGE_RW) &&
- !(paging_mode_external(d) && (d != curr->domain)) &&
+ ((l1e_owner == pg_owner) || !paging_mode_external(pg_owner)) &&
!get_page_type(page, PGT_writable_page) )
goto could_not_pin;
@@ -798,8 +801,7 @@ get_page_from_l1e(
if ( is_xen_heap_page(page) )
{
if ( (l1f & _PAGE_RW) &&
- !(unlikely(paging_mode_external(d) &&
- (d != curr->domain))) )
+ ((l1e_owner == pg_owner) || !paging_mode_external(pg_owner)) )
put_page_type(page);
put_page(page);
MEM_LOG("Attempt to change cache attributes of Xen heap page");
@@ -820,10 +822,10 @@ get_page_from_l1e(
could_not_pin:
MEM_LOG("Error getting mfn %lx (pfn %lx) from L1 entry %" PRIpte
- " for dom%d",
+ " for l1e_owner=%d, pg_owner=%d",
mfn, get_gpfn_from_mfn(mfn),
- l1e_get_intpte(l1e), d->domain_id);
- if ( owner != NULL )
+ l1e_get_intpte(l1e), l1e_owner->domain_id, pg_owner->domain_id);
+ if ( real_pg_owner != NULL )
put_page(page);
return 0;
}
@@ -996,19 +998,18 @@ get_page_from_l4e(
#define unadjust_guest_l3e(_p, _d) ((void)(_d))
#endif
-void put_page_from_l1e(l1_pgentry_t l1e, struct domain *d)
+void put_page_from_l1e(l1_pgentry_t l1e, struct domain *l1e_owner)
{
unsigned long pfn = l1e_get_pfn(l1e);
struct page_info *page;
- struct domain *e;
+ struct domain *pg_owner;
struct vcpu *v;
if ( !(l1e_get_flags(l1e) & _PAGE_PRESENT) || is_iomem_page(pfn) )
return;
page = mfn_to_page(pfn);
-
- e = page_get_owner(page);
+ pg_owner = page_get_owner(page);
/*
* Check if this is a mapping that was established via a grant reference.
@@ -1024,17 +1025,17 @@ void put_page_from_l1e(l1_pgentry_t l1e,
* Xen. All active grants can safely be cleaned up when the domain dies.)
*/
if ( (l1e_get_flags(l1e) & _PAGE_GNTTAB) &&
- !d->is_shutting_down && !d->is_dying )
+ !l1e_owner->is_shutting_down && !l1e_owner->is_dying )
{
MEM_LOG("Attempt to implicitly unmap a granted PTE %" PRIpte,
l1e_get_intpte(l1e));
- domain_crash(d);
+ domain_crash(l1e_owner);
}
/* Remember we didn't take a type-count of foreign writable mappings
* to paging-external domains */
if ( (l1e_get_flags(l1e) & _PAGE_RW) &&
- !(unlikely((e != d) && paging_mode_external(e))) )
+ ((l1e_owner == pg_owner) || !paging_mode_external(pg_owner)) )
{
put_page_and_type(page);
}
@@ -1044,9 +1045,9 @@ void put_page_from_l1e(l1_pgentry_t l1e,
if ( unlikely(((page->u.inuse.type_info & PGT_type_mask) ==
PGT_seg_desc_page)) &&
unlikely(((page->u.inuse.type_info & PGT_count_mask) != 0)) &&
- (d == e) )
- {
- for_each_vcpu ( d, v )
+ (l1e_owner == pg_owner) )
+ {
+ for_each_vcpu ( pg_owner, v )
invalidate_shadow_ldt(v, 1);
}
put_page(page);
@@ -1137,7 +1138,7 @@ static int alloc_l1_table(struct page_in
for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ )
{
if ( is_guest_l1_slot(i) &&
- unlikely(!get_page_from_l1e(pl1e[i], d)) )
+ unlikely(!get_page_from_l1e(pl1e[i], d, d)) )
goto fail;
adjust_guest_l1e(pl1e[i], d);
@@ -1716,7 +1717,7 @@ static int mod_l1_entry(l1_pgentry_t *pl
return rc;
}
- if ( unlikely(!get_page_from_l1e(nl1e, FOREIGNDOM)) )
+ if ( unlikely(!get_page_from_l1e(nl1e, d, FOREIGNDOM)) )
return 0;
adjust_guest_l1e(nl1e, d);
@@ -4224,7 +4225,7 @@ static int ptwr_emulated_update(
/* Check the new PTE. */
nl1e = l1e_from_intpte(val);
- if ( unlikely(!get_page_from_l1e(nl1e, d)) )
+ if ( unlikely(!get_page_from_l1e(nl1e, d, d)) )
{
if ( is_pv_32bit_domain(d) && (bytes == 4) && (unaligned_addr & 4) &&
!do_cmpxchg && (l1e_get_flags(nl1e) & _PAGE_PRESENT) )
diff -r 07cf79dfb59c -r c4b048ce6a4b xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c Wed Jun 03 12:59:44 2009 +0100
+++ b/xen/arch/x86/mm/shadow/multi.c Wed Jun 03 14:40:34 2009 +0100
@@ -816,7 +816,7 @@ shadow_get_page_from_l1e(shadow_l1e_t sl
if ( !shadow_mode_refcounts(d) )
return 1;
- res = get_page_from_l1e(sl1e, d);
+ res = get_page_from_l1e(sl1e, d, d);
// If a privileged domain is attempting to install a map of a page it does
// not own, we let it succeed anyway.
@@ -828,7 +828,7 @@ shadow_get_page_from_l1e(shadow_l1e_t sl
(d != owner) &&
IS_PRIV_FOR(d, owner))
{
- res = get_page_from_l1e(sl1e, owner);
+ res = get_page_from_l1e(sl1e, d, owner);
SHADOW_PRINTK("privileged domain %d installs map of mfn %05lx "
"which is owned by domain %d: %s\n",
d->domain_id, mfn_x(mfn), owner->domain_id,
diff -r 07cf79dfb59c -r c4b048ce6a4b xen/include/asm-x86/mm.h
--- a/xen/include/asm-x86/mm.h Wed Jun 03 12:59:44 2009 +0100
+++ b/xen/include/asm-x86/mm.h Wed Jun 03 14:40:34 2009 +0100
@@ -285,8 +285,9 @@ int get_page_type(struct page_info *pag
int get_page_type(struct page_info *page, unsigned long type);
int put_page_type_preemptible(struct page_info *page);
int get_page_type_preemptible(struct page_info *page, unsigned long type);
-int get_page_from_l1e(l1_pgentry_t l1e, struct domain *d);
-void put_page_from_l1e(l1_pgentry_t l1e, struct domain *d);
+int get_page_from_l1e(
+ l1_pgentry_t l1e, struct domain *l1e_owner, struct domain *pg_owner);
+void put_page_from_l1e(l1_pgentry_t l1e, struct domain *l1e_owner);
static inline void put_page_and_type(struct page_info *page)
{
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