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authorAmit Shah <amit.shah@redhat.com>2008-10-27 09:04:17 +0000
committerAvi Kivity <avi@redhat.com>2008-12-31 16:51:48 +0200
commit25022acc3dd5f0b54071c7ba7c371860f2971b52 (patch)
tree819a2ae0e14c8f22050ad847a42e4f9058f9f273
parentb8222ad2e52fd2c0c4e5e1c53e65d131f911b767 (diff)
downloadop-kernel-dev-25022acc3dd5f0b54071c7ba7c371860f2971b52.zip
op-kernel-dev-25022acc3dd5f0b54071c7ba7c371860f2971b52.tar.gz
KVM: SVM: Set the 'g' bit of the cs selector for cross-vendor migration
The hardware does not set the 'g' bit of the cs selector and this breaks migration from amd hosts to intel hosts. Set this bit if the segment limit is beyond 1 MB. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
-rw-r--r--arch/x86/kvm/svm.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 05efc4e..665008d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -772,6 +772,15 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
var->l = (s->attrib >> SVM_SELECTOR_L_SHIFT) & 1;
var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;
+
+ /*
+ * SVM always stores 0 for the 'G' bit in the CS selector in
+ * the VMCB on a VMEXIT. This hurts cross-vendor migration:
+ * Intel's VMENTRY has a check on the 'G' bit.
+ */
+ if (seg == VCPU_SREG_CS)
+ var->g = s->limit > 0xfffff;
+
var->unusable = !var->present;
}
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