[Xen-changelog] [xen-3.0-testing] [HVM] Fix shadow mode to not corrupt frame 0's page_info struct.

[Xen patchbot-3.0-testing <patchbot-3.0-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID b6a04d27b6e16cf16a3bdbad61a00719df62b8d3
# Parent  18e8e613deb9050de02eb8ba9138185e33240e7f
[HVM] Fix shadow mode to not corrupt frame 0's page_info struct.
Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx>
xen-unstable changeset:   10189:ec1e371ec3208f771595da6c82baae4cd9a441f5
xen-unstable date:        Wed May 31 07:25:59 2006 +0100
---
 xen/arch/x86/shadow.c        |    3 ++-
 xen/arch/x86/shadow32.c      |    3 ++-
 xen/include/asm-x86/shadow.h |   12 +++++++++---
 3 files changed, 13 insertions(+), 5 deletions(-)

diff -r 18e8e613deb9 -r b6a04d27b6e1 xen/arch/x86/shadow.c
--- a/xen/arch/x86/shadow.c     Tue May 30 18:14:05 2006 +0100
+++ b/xen/arch/x86/shadow.c     Wed May 31 07:32:04 2006 +0100
@@ -1688,7 +1688,8 @@ static int resync_all(struct domain *d, 
                         unshadow_l1 = 1;
                     else {
                         need_flush |= error;
-                        set_guest_back_ptr(d, *sl1e_p, smfn, i);
+                        if ( l1e_get_flags(*sl1e_p) & _PAGE_PRESENT )
+                            set_guest_back_ptr(d, *sl1e_p, smfn, i);
                     }
                     // can't update snapshots of linear page tables -- they
                     // are used multiple times...
diff -r 18e8e613deb9 -r b6a04d27b6e1 xen/arch/x86/shadow32.c
--- a/xen/arch/x86/shadow32.c   Tue May 30 18:14:05 2006 +0100
+++ b/xen/arch/x86/shadow32.c   Wed May 31 07:32:04 2006 +0100
@@ -2678,7 +2678,8 @@ static int resync_all(struct domain *d, 
                         unshadow_l1 = 1;
                     else {
                         need_flush |= error;
-                        set_guest_back_ptr(d, shadow1[i], smfn, i);
+                        if ( l1e_get_flags(shadow1[i]) & _PAGE_PRESENT )
+                            set_guest_back_ptr(d, shadow1[i], smfn, i);
                     }
 
                     // can't update snapshots of linear page tables -- they
diff -r 18e8e613deb9 -r b6a04d27b6e1 xen/include/asm-x86/shadow.h
--- a/xen/include/asm-x86/shadow.h      Tue May 30 18:14:05 2006 +0100
+++ b/xen/include/asm-x86/shadow.h      Wed May 31 07:32:04 2006 +0100
@@ -762,10 +762,16 @@ static inline void set_guest_back_ptr(
         unsigned long gmfn;
 
         ASSERT(shadow_lock_is_acquired(d));
+        ASSERT( smfn );
         gmfn = l1e_get_pfn(spte);
-        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;
+        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;
+        }
     }
 }
 

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