From: Andre Przywara <andre.przywara@amd.com>
Date: Tue, 28 Apr 2009 10:45:43 +0000 (+0200)
Subject: KVM: SVM: Fix cross vendor migration issue in segment segment descriptor
X-Git-Tag: kvm-86rc2~37
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ff1ee7e35583e47b29b44e8c5bee495e2d581d49;p=users%2Fdwmw2%2Flinux.git

KVM: SVM: Fix cross vendor migration issue in segment segment descriptor

On AMD CPUs sometimes the DB bit in the stack segment
descriptor is left as 1, although the whole segment has
been made unusable. Clear it here to pass an Intel VMX
entry check when cross vendor migrating.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1647e81696aad..61453e6becbd2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -804,6 +804,15 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
 		if (!var->unusable)
 			var->type |= 0x1;
 		break;
+	case VCPU_SREG_SS:
+		/* On AMD CPUs sometimes the DB bit in the segment
+		 * descriptor is left as 1, although the whole segment has
+		 * been made unusable. Clear it here to pass an Intel VMX
+		 * entry check when cross vendor migrating.
+		 */
+		if (var->unusable)
+			var->db = 0;
+		break;
 	}
 }