KVM: x86 emulator: fix xchg instruction emulation

Commit Message

Wei Yongjun July 14, 2010, 5:15 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d94811e..ac63f6f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3560,6 +3560,8 @@  static int emulator_cmpxchg_emulated(unsigned long addr,
 		goto emul_write;
 
 	page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+	if (is_error_page(page))
+		goto emul_write;
 
 	kaddr = kmap_atomic(page, KM_USER0);
 	kaddr += offset_in_page(gpa);