Re: [PATCH v2 3/4] KVM: SVM: Don't advertise Bus Lock Detect to guest if SVM support is missing

From: Jim Mattson
Date: Fri Jul 12 2024 - 19:33:30 EST


On Fri, Jul 12, 2024 at 2:41 AM Ravi Bangoria <ravi.bangoria@xxxxxxx> wrote:
>
> If host supports Bus Lock Detect, KVM advertises it to guests even if
> SVM support is absent. Additionally, guest wouldn't be able to use it
> despite guest CPUID bit being set. Fix it by unconditionally clearing
> the feature bit in KVM cpu capability.
>
> Reported-by: Jim Mattson <jmattson@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/CALMp9eRet6+v8Y1Q-i6mqPm4hUow_kJNhmVHfOV8tMfuSS=tVg@xxxxxxxxxxxxxx
> Fixes: 76ea438b4afc ("KVM: X86: Expose bus lock debug exception to guest")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>