[Xen-changelog] Bug fix for shadow external mode (i.e. VMX) operation,

[BitKeeper Bot <riel@xxxxxxxxxxx>]

ChangeSet 1.1430, 2005/05/17 14:20:17+01:00, maf46@xxxxxxxxxxxxxxxxx

        Bug fix for shadow external mode (i.e. VMX) operation,
        fixing an overly aggressive new ASSERT added with the light weight
        shadow code.



 domain.c |    3 ++-
 shadow.c |   10 ++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)


diff -Nru a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c     2005-05-17 10:04:57 -04:00
+++ b/xen/arch/x86/domain.c     2005-05-17 10:04:57 -04:00
@@ -364,7 +364,8 @@
         /* Put the domain in shadow mode even though we're going to be using
          * the shared 1:1 page table initially. It shouldn't hurt */
         shadow_mode_enable(ed->domain,
-                           
SHM_enable|SHM_refcounts|SHM_translate|SHM_external);
+                           SHM_enable|SHM_write_all|SHM_refcounts|
+                           SHM_translate|SHM_external);
     }
 
     return 0;
diff -Nru a/xen/arch/x86/shadow.c b/xen/arch/x86/shadow.c
--- a/xen/arch/x86/shadow.c     2005-05-17 10:04:57 -04:00
+++ b/xen/arch/x86/shadow.c     2005-05-17 10:04:57 -04:00
@@ -2307,9 +2307,10 @@
             // guest page.
             // This only applies when we have writable page tables.
             //
-            if ( (stype == PGT_l1_shadow) && !VM_ASSIST(d, 
VMASST_TYPE_writable_pagetables) )
-                continue;
-            if ( (stype != PGT_l1_shadow) && !shadow_mode_write_all(d) )
+            if ( !shadow_mode_write_all(d) &&
+                 !((stype == PGT_l1_shadow) &&
+                   VM_ASSIST(d, VMASST_TYPE_writable_pagetables)) )
+                // Page is not writable -- no resync necessary
                 continue;
         }
 
@@ -2336,7 +2337,8 @@
             l1_pgentry_t *shadow1 = shadow;
             l1_pgentry_t *snapshot1 = snapshot;
 
-            ASSERT(VM_ASSIST(d, VMASST_TYPE_writable_pagetables));
+            ASSERT(VM_ASSIST(d, VMASST_TYPE_writable_pagetables) ||
+                   shadow_mode_write_all(d));
 
             if ( !shadow_mode_refcounts(d) )
                 revalidate_l1(d, guest1, snapshot1);

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