2016-07-14 16:09 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: [...] > > This is not necessary because this is how KVM computes > CPUID[EAX=7,EBX=0].ECX: > > unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0; > ... > const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | F(UMIP); > ... > // Mask userspace-provided value against supported features > entry->ecx &= kvm_cpuid_7_0_ecx_x86_features; > // Mask userspace-provided value against host features > cpuid_mask(&entry->ecx, CPUID_7_ECX); > // Finally add emulated features > entry->ecx |= f_umip; I think you mean: - entry->ecx -> userspace-provided value - kvm_cpuid_7_0_ecx_x86_features -> supported features - CPUID_7_ECX -> host features However, entry->ecx is returned by cpuid instruction (do_cpuid_1_ent()), so why it is a userspace-provided value? Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
