On 08/07/19 09:09, Jing Liu wrote:
> It seems the two func are introduced by 2b5e97e, as paravirtual cpuid.
> But when searching KVM_CPUID_SIGNATURE, there seems no caller requesting
> this cpuid. Meanwhile, I felt curious if KVM_CPUID_FEATURES is still in
> use but it seems kvm_update_cpuid() uses that. Not sure which spec
> introduces the latest pv cpuid.
Yes, KVM_CPUID_SIGNATURE is generally not very interesting for
userspace. But KVM_CPUID_FEATURES is called here:
for (w = 0; w < FEATURE_WORDS; w++) {
/* Override only features that weren't set explicitly
* by the user.
*/
env->features[w] |=
x86_cpu_get_supported_feature_word(w, cpu->migratable) &
~env->user_features[w] & \
~feature_word_info[w].no_autoenable_flags;
}
Paolo
