KVM: x86: emulator_cmpxchg_emulated should mark_page_dirty

emulator_cmpxchg_emulated writes to guest memory, therefore it should
update the dirty bitmap accordingly.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6530019116b0..4cca45853dfe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4399,6 +4399,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
         if (!exchanged)
                 return X86EMUL_CMPXCHG_FAILED;
 
+        mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
         kvm_mmu_pte_write(vcpu, gpa, new, bytes);
 
         return X86EMUL_CONTINUE;