| Message ID | 20240806125442.1603-4-ravi.bangoria@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/cpu: Add Bus Lock Detect support for AMD | expand |
On 8/6/24 07:54, Ravi Bangoria 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@google.com> > Closes: https://lore.kernel.org/r/CALMp9eRet6+v8Y1Q-i6mqPm4hUow_kJNhmVHfOV8tMfuSS=tVg@mail.gmail.com > Fixes: 76ea438b4afc ("KVM: X86: Expose bus lock debug exception to guest") > Cc: stable@vger.kernel.org > Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> > Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/kvm/svm/svm.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index c115d26844f7..85631112c872 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -5223,6 +5223,9 @@ static __init void svm_set_cpu_caps(void) > > /* CPUID 0x8000001F (SME/SEV features) */ > sev_set_cpu_caps(); > + > + /* Don't advertise Bus Lock Detect to guest if SVM support is absent */ > + kvm_cpu_cap_clear(X86_FEATURE_BUS_LOCK_DETECT); > } > > static __init int svm_hardware_setup(void)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index c115d26844f7..85631112c872 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5223,6 +5223,9 @@ static __init void svm_set_cpu_caps(void) /* CPUID 0x8000001F (SME/SEV features) */ sev_set_cpu_caps(); + + /* Don't advertise Bus Lock Detect to guest if SVM support is absent */ + kvm_cpu_cap_clear(X86_FEATURE_BUS_LOCK_DETECT); } static __init int svm_hardware_setup(void)
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@google.com> Closes: https://lore.kernel.org/r/CALMp9eRet6+v8Y1Q-i6mqPm4hUow_kJNhmVHfOV8tMfuSS=tVg@mail.gmail.com Fixes: 76ea438b4afc ("KVM: X86: Expose bus lock debug exception to guest") Cc: stable@vger.kernel.org Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Reviewed-by: Jim Mattson <jmattson@google.com> --- arch/x86/kvm/svm/svm.c | 3 +++ 1 file changed, 3 insertions(+)