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authorMarcelo Tosatti <mtosatti@redhat.com>2010-12-22 09:01:57 -0200
committerAvi Kivity <avi@redhat.com>2011-01-12 11:31:13 +0200
commite49146dce8c3dc6f4485c1904b6587855f393e71 (patch)
tree1a7db0516cee7ff2810445e16d21dadd960237af
parent16d8f72f70a85ce333788204a69318827130ca75 (diff)
downloadblackbird-op-linux-e49146dce8c3dc6f4485c1904b6587855f393e71.tar.gz
blackbird-op-linux-e49146dce8c3dc6f4485c1904b6587855f393e71.zip
KVM: MMU: only write protect mappings at pagetable level
If a pagetable contains a writeable large spte, all of its sptes will be write protected, including non-leaf ones, leading to endless pagefaults. Do not write protect pages above PT_PAGE_TABLE_LEVEL, as the spte fault paths assume non-leaf sptes are writable. Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
-rw-r--r--arch/x86/kvm/mmu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b77a5ba398be..a2127f82e786 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3445,6 +3445,9 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
if (!test_bit(slot, sp->slot_bitmap))
continue;
+ if (sp->role.level != PT_PAGE_TABLE_LEVEL)
+ continue;
+
pt = sp->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
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