KVM: SVM: Fix cross vendor migration issue with unusable bit
AMDs VMCB does not have an explicit unusable segment descriptor field,
so we emulate it by using "not present". This has to be setup before
the fixups, because this field is used there.
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 1821c20..9184e32 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -796,6 +796,11 @@
var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;
+ /* AMD's VMCB does not have an explicit unusable field, so emulate it
+ * for cross vendor migration purposes by "not present"
+ */
+ var->unusable = !var->present || (var->type == 0);
+
switch (seg) {
case VCPU_SREG_CS:
/*
@@ -827,8 +832,6 @@
var->type |= 0x1;
break;
}
-
- var->unusable = !var->present;
}
static int svm_get_cpl(struct kvm_vcpu *vcpu)