| Message ID | 20200201185218.24473-24-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Introduce KVM cpu caps | expand |
Sean Christopherson <sean.j.christopherson@intel.com> writes: > Clear the output regs for the main CPUID 0x14 leaf (index=0) if Intel PT > isn't exposed to the guest. Leaf 0x14 enumerates Intel PT capabilities > and should return zeroes if PT is not supported. Incorrectly reporting > PT capabilities is essentially a cosmetic error, i.e. doesn't negatively > affect any known userspace/kernel, as the existence of PT itself is > correctly enumerated via CPUID 0x7. > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > arch/x86/kvm/cpuid.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index d3c93b94abc3..056faf27b14b 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -663,8 +663,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) > break; > /* Intel PT */ > case 0x14: > - if (!f_intel_pt) > + if (!f_intel_pt) { > + entry->eax = entry->ebx = entry->ecx = entry->edx = 0; > break; > + } > > for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) { > if (!do_host_cpuid(array, function, i)) Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d3c93b94abc3..056faf27b14b 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -663,8 +663,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) break; /* Intel PT */ case 0x14: - if (!f_intel_pt) + if (!f_intel_pt) { + entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; + } for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) { if (!do_host_cpuid(array, function, i))
Clear the output regs for the main CPUID 0x14 leaf (index=0) if Intel PT isn't exposed to the guest. Leaf 0x14 enumerates Intel PT capabilities and should return zeroes if PT is not supported. Incorrectly reporting PT capabilities is essentially a cosmetic error, i.e. doesn't negatively affect any known userspace/kernel, as the existence of PT itself is correctly enumerated via CPUID 0x7. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/cpuid.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)