| Message ID | 20220929225203.2234702-5-jmattson@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/6] KVM: x86: Mask off reserved bits in CPUID.80000001H | expand |
On Thu, Sep 29, 2022, Jim Mattson wrote: > KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM > actually supports. The following ranges of CPUID.8000001EH are reserved > and should be masked off: > EBX[31:16] > ECX[31:11] LOL, APM is buggy, it says all bits in ECX are reserved. 31:0 - Reserved. 10:8 NodesPerProcessor 7:0 NodeId Advertising NodeId seems all kinds of wrong :-( > EDX[31:0] > > Fixes: 382409b4c43e ("kvm: x86: Include CPUID leaf 0x8000001e in kvm's supported CPUID") > Signed-off-by: Jim Mattson <jmattson@google.com> > --- > arch/x86/kvm/cpuid.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 5d1ec390aa45..576cbcf489ce 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -1179,6 +1179,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) > entry->ebx = entry->ecx = entry->edx = 0; > break; > case 0x8000001e: > + entry->ebx &= ~GENMASK(31, 16); > + entry->ecx &= ~GENMASK(31, 11); > + entry->edx = 0; > break; > case 0x8000001F: > if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) { > -- > 2.38.0.rc1.362.ged0d419d3c-goog >
On 10/20/22 00:53, Sean Christopherson wrote: > On Thu, Sep 29, 2022, Jim Mattson wrote: >> KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM >> actually supports. The following ranges of CPUID.8000001EH are reserved >> and should be masked off: >> EBX[31:16] >> ECX[31:11] > LOL, APM is buggy, it says all bits in ECX are reserved. > > 31:0 - Reserved. > 10:8 NodesPerProcessor > 7:0 NodeId > > Advertising NodeId seems all kinds of wrong
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5d1ec390aa45..576cbcf489ce 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1179,6 +1179,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) entry->ebx = entry->ecx = entry->edx = 0; break; case 0x8000001e: + entry->ebx &= ~GENMASK(31, 16); + entry->ecx &= ~GENMASK(31, 11); + entry->edx = 0; break; case 0x8000001F: if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) {
KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM actually supports. The following ranges of CPUID.8000001EH are reserved and should be masked off: EBX[31:16] ECX[31:11] EDX[31:0] Fixes: 382409b4c43e ("kvm: x86: Include CPUID leaf 0x8000001e in kvm's supported CPUID") Signed-off-by: Jim Mattson <jmattson@google.com> --- arch/x86/kvm/cpuid.c | 3 +++ 1 file changed, 3 insertions(+)