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[05/13] KVM: VMX: Allow real mode emulation using vm86 with dpl=0

Message ID 1345558030-29370-6-git-send-email-avi@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Avi Kivity Aug. 21, 2012, 2:07 p.m. UTC
Real mode is always entered from protected mode with dpl=0.  Since
the dpl doesn't affect execution, and we already override it to 3
in the vmcs (as vmx requires), we can allow execution in that state.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e94b90b..4f3d6ac 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3318,7 +3318,7 @@  static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
 		return false;
 	if (var.limit != 0xffff)
 		return false;
-	if (ar != 0xf3)
+	if ((ar | (3 << AR_DPL_SHIFT)) != 0xf3)
 		return false;
 
 	return true;