From 54950bfe2b69cdc06ef753872b5225e54eb73506 Mon Sep 17 00:00:00 2001 From: Ravi Bangoria Date: Thu, 8 Aug 2024 06:29:36 +0000 Subject: [PATCH] KVM: SVM: Don't advertise Bus Lock Detect to guest if SVM support is missing 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 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 Reviewed-by: Jim Mattson Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/r/20240808062937.1149-4-ravi.bangoria@amd.com Signed-off-by: Sean Christopherson --- 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 b11454151f25..5ab2c92c7331 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5236,6 +5236,9 @@ 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)