3.16.68-rc1 review patch. If anyone has any objections, please let me know.
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From: Eduardo Habkost ehabkost@redhat.com
commit d7b09c827a6cf291f66637a36f46928dd1423184 upstream.
Months ago, we have added code to allow direct access to MSR_IA32_SPEC_CTRL to the guest, which makes STIBP available to guests. This was implemented by commits d28b387fb74d ("KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL") and b2ac58f90540 ("KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL").
However, we never updated GET_SUPPORTED_CPUID to let userspace know that STIBP can be enabled in CPUID. Fix that by updating kvm_cpuid_8000_0008_ebx_x86_features and kvm_cpuid_7_0_edx_x86_features.
Signed-off-by: Eduardo Habkost ehabkost@redhat.com Reviewed-by: Jim Mattson jmattson@google.com Reviewed-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Thomas Gleixner tglx@linutronix.de [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -303,7 +303,7 @@ static inline int __do_cpuid_ent(struct /* cpuid 0x80000008.ebx */ const u32 kvm_cpuid_8000_0008_ebx_x86_features = F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | - F(AMD_SSB_NO); + F(AMD_SSB_NO) | F(AMD_STIBP);
/* cpuid 0xC0000001.edx */ const u32 kvm_supported_word5_x86_features = @@ -319,7 +319,8 @@ static inline int __do_cpuid_ent(struct
/* cpuid 7.0.edx*/ const u32 kvm_cpuid_7_0_edx_x86_features = - F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES); + F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | + F(INTEL_STIBP);
/* all calls to cpuid_count() should be made on the same cpu */ get_cpu();