Commit f4cfcd2d authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini

KVM: x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally

This msr is only available when the host supports WAITPKG feature.

This breaks a nested guest, if the L1 hypervisor is set to ignore
unknown msrs, because the only other safety check that the
kernel does is that it attempts to read the msr and
rejects it if it gets an exception.

Cc: stable@vger.kernel.org
Fixes: 6e3ba4ab ("KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL")
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200523161455.3940-3-mlevitsk@redhat.com>
Reviewed-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 0abcc8f6
...@@ -5242,6 +5242,10 @@ static void kvm_init_msr_list(void) ...@@ -5242,6 +5242,10 @@ static void kvm_init_msr_list(void)
if (!kvm_cpu_cap_has(X86_FEATURE_RDTSCP)) if (!kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
continue; continue;
break; break;
case MSR_IA32_UMWAIT_CONTROL:
if (!kvm_cpu_cap_has(X86_FEATURE_WAITPKG))
continue;
break;
case MSR_IA32_RTIT_CTL: case MSR_IA32_RTIT_CTL:
case MSR_IA32_RTIT_STATUS: case MSR_IA32_RTIT_STATUS:
if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT)) if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT))
......
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