Commit 19bca6ab75d8 ("KVM: SVM: Fix cross vendor migration issue with
unusable bit") added checking type when setting unusable.
So unusable can be set if present is 0 OR type is 0.
According to the AMD processor manual, long mode ignores the type value
in segment descriptor. And type can be 0 if it is read-only data segment.
Therefore type value is not related to unusable flag.
This patch is based on linux-next v4.12.0-rc3.
Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx>
---
arch/x86/kvm/svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 183ddb2..a654372 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1807,7 +1807,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
* 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);
+ var->unusable = !var->present;
switch (seg) {
case VCPU_SREG_TR:
--
2.5.0
