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authorMarcelo Tosatti <mtosatti@redhat.com>2014-02-24 13:59:32 -0300
committerPaolo Bonzini <pbonzini@redhat.com>2014-02-26 17:23:32 +0100
commit404381c5839d67aa0c275ad1da96ef3d3928ca2c (patch)
tree428dc29ebd433849b621e6238e93e33f9cfca0e2 /arch/x86
parent6d0abeca3242a88cab8232e4acd7e2bf088f3bc2 (diff)
KVM: MMU: drop read-only large sptes when creating lower level sptes
Read-only large sptes can be created due to read-only faults as follows: - QEMU pagetable entry that maps guest memory is read-only due to COW. - Guest read faults such memory, COW is not broken, because it is a read-only fault. - Enable dirty logging, large spte not nuked because it is read-only. - Write-fault on such memory causes guest to loop endlessly (which must go down to level 1 because dirty logging is enabled). Fix by dropping large spte when necessary. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/mmu.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e50425d0f5f..9b531351a58 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2672,6 +2672,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
break;
}
+ drop_large_spte(vcpu, iterator.sptep);
if (!is_shadow_present_pte(*iterator.sptep)) {
u64 base_addr = iterator.addr;