On Thu, Aug 15, 2019 at 12:41 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > The AMD_* bits have to be set from the vendor-independent > feature and bug flags, because KVM_GET_SUPPORTED_CPUID does not care > about the vendor and they should be set on Intel processors as well. > On top of this, SSBD, STIBP and AMD_SSB_NO bit were not set, and > VIRT_SSBD does not have to be added manually because it is a > cpufeature that comes directly from the host's CPUID bit. > > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> On AMD systems, aren't AMD_SSBD, AMD_STIBP, and AMD_SSB_NO set by inheritance from the host: /* cpuid 0x80000008.ebx */ const u32 kvm_cpuid_8000_0008_ebx_x86_features = F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON); I am curious why the cross-vendor settings go only one way. For example, you set AMD_STIBP on Intel processors that have STIBP, but you do not set INTEL_STIBP on AMD processors that have STIBP? Similarly, you set AMD_SSB_NO for Intel processors that are immune to SSB, but you do not set IA32_ARCH_CAPABILITIES.SSB_NO for AMD processors that are immune to SSB? Perhaps there is another patch coming for reporting Intel bits on AMD?