[PATCH v2 1/2] KVM: SVM: Allow KVM_SET_NESTED_STATE to clear GIF when SVME==0

Jim Mattson posted 2 patches 2 months, 1 week ago
There is a newer version of this series
[PATCH v2 1/2] KVM: SVM: Allow KVM_SET_NESTED_STATE to clear GIF when SVME==0
Posted by Jim Mattson 2 months, 1 week ago
GIF==0 together with EFER.SVME==0 is a valid architectural
state. Don't return -EINVAL for KVM_SET_NESTED_STATE when this
combination is specified.

Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE")
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/svm/nested.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index a6443feab252..db0d4f2b128c 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1798,8 +1798,8 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	 * EFER.SVME, but EFER.SVME still has to be 1 for VMRUN to succeed.
 	 */
 	if (!(vcpu->arch.efer & EFER_SVME)) {
-		/* GIF=1 and no guest mode are required if SVME=0.  */
-		if (kvm_state->flags != KVM_STATE_NESTED_GIF_SET)
+		/* GUEST_MODE must be clear when SVME==0 */
+		if (kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE)
 			return -EINVAL;
 	}
 
-- 
2.51.0.740.g6adb054d12-goog
Re: [PATCH v2 1/2] KVM: SVM: Allow KVM_SET_NESTED_STATE to clear GIF when SVME==0
Posted by Yosry Ahmed 2 months, 1 week ago
On Thu, Oct 09, 2025 at 03:31:33PM -0700, Jim Mattson wrote:
> GIF==0 together with EFER.SVME==0 is a valid architectural
> state. Don't return -EINVAL for KVM_SET_NESTED_STATE when this
> combination is specified.
> 
> Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE")
> Signed-off-by: Jim Mattson <jmattson@google.com>

Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>

> ---
>  arch/x86/kvm/svm/nested.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index a6443feab252..db0d4f2b128c 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -1798,8 +1798,8 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
>  	 * EFER.SVME, but EFER.SVME still has to be 1 for VMRUN to succeed.
>  	 */
>  	if (!(vcpu->arch.efer & EFER_SVME)) {
> -		/* GIF=1 and no guest mode are required if SVME=0.  */
> -		if (kvm_state->flags != KVM_STATE_NESTED_GIF_SET)
> +		/* GUEST_MODE must be clear when SVME==0 */
> +		if (kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE)
>  			return -EINVAL;
>  	}
>  
> -- 
> 2.51.0.740.g6adb054d12-goog
>