Mailing List Archive

# HG changeset patch
# User kfraser@dhcp93.uk.xensource.com
# Node ID 121ec8b952d33a358e6c6ab65493e0b47e56781d
# Parent 09d9d6e7b9851cfb2206395ced55b4769e164b4a
[HVM] Fix set_guest_back_ptr to ignore empty PTEs.
Signed-off-by: Keir Fraser <keir@xensource.com>
---
xen/include/asm-x86/shadow.h | 37 ++++++++++++++++++++-----------------
1 files changed, 20 insertions(+), 17 deletions(-)

diff -r 09d9d6e7b985 -r 121ec8b952d3 xen/include/asm-x86/shadow.h
--- a/xen/include/asm-x86/shadow.h Thu Jun 01 10:34:21 2006 +0100
+++ b/xen/include/asm-x86/shadow.h Thu Jun 01 10:50:33 2006 +0100
@@ -756,23 +756,26 @@ shadow_unpin(unsigned long smfn)
* when working on finer-gained locks for shadow.
*/
static inline void set_guest_back_ptr(
- struct domain *d, l1_pgentry_t spte, unsigned long smfn, unsigned int index)
-{
- if ( shadow_mode_external(d) ) {
- unsigned long gmfn;
-
- ASSERT(shadow_lock_is_acquired(d));
- ASSERT( smfn );
- gmfn = l1e_get_pfn(spte);
- ASSERT( gmfn );
- if ( l1e_get_flags(spte) & _PAGE_RW )
- {
- mfn_to_page(gmfn)->tlbflush_timestamp = smfn;
- mfn_to_page(gmfn)->u.inuse.type_info &= ~PGT_va_mask;
- mfn_to_page(gmfn)->u.inuse.type_info |=
- (unsigned long) index << PGT_va_shift;
- }
- }
+ struct domain *d, l1_pgentry_t spte,
+ unsigned long smfn, unsigned int index)
+{
+ struct page_info *gpage;
+
+ ASSERT(shadow_lock_is_acquired(d));
+
+ if ( !shadow_mode_external(d) ||
+ ((l1e_get_flags(spte) & (_PAGE_PRESENT|_PAGE_RW)) !=
+ (_PAGE_PRESENT|_PAGE_RW)) )
+ return;
+
+ gpage = l1e_get_page(spte);
+
+ ASSERT(smfn != 0);
+ ASSERT(page_to_mfn(gpage) != 0);
+
+ gpage->tlbflush_timestamp = smfn;
+ gpage->u.inuse.type_info &= ~PGT_va_mask;
+ gpage->u.inuse.type_info |= (unsigned long)index << PGT_va_shift;
}

/************************************************************************/

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