* [PATCH] KVM: SVM: ignore type when setting segment registers
@ 2017-05-30 13:24 Gioh Kim
2017-05-30 15:05 ` Radim Krčmář
0 siblings, 1 reply; 3+ messages in thread
From: Gioh Kim @ 2017-05-30 13:24 UTC (permalink / raw)
To: joro, pbonzini, rkrcmar; +Cc: x86, kvm, linux-kernel, Gioh Kim
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@profitbricks.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: SVM: ignore type when setting segment registers
2017-05-30 13:24 [PATCH] KVM: SVM: ignore type when setting segment registers Gioh Kim
@ 2017-05-30 15:05 ` Radim Krčmář
2017-05-30 16:04 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Radim Krčmář @ 2017-05-30 15:05 UTC (permalink / raw)
To: Gioh Kim; +Cc: joro, pbonzini, x86, kvm, linux-kernel
2017-05-30 15:24+0200, Gioh Kim:
> This patch is based on linux-next v4.12.0-rc3.
(I'd omit this.)
> Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
> ---
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: SVM: ignore type when setting segment registers
2017-05-30 15:05 ` Radim Krčmář
@ 2017-05-30 16:04 ` Paolo Bonzini
0 siblings, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2017-05-30 16:04 UTC (permalink / raw)
To: Radim Krčmář, Gioh Kim; +Cc: joro, x86, kvm, linux-kernel
On 30/05/2017 17:05, Radim Krčmář wrote:
> 2017-05-30 15:24+0200, Gioh Kim:
>> This patch is based on linux-next v4.12.0-rc3.
>
> (I'd omit this.)
>
>> Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
>> ---
>
> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-05-30 13:24 [PATCH] KVM: SVM: ignore type when setting segment registers Gioh Kim
2017-05-30 15:05 ` Radim Krčmář
2017-05-30 16:04 ` Paolo Bonzini
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