On Fri, Feb 09, 2018 at 09:41:41AM +0100, Paolo Bonzini wrote: > On 08/02/2018 19:12, Eduardo Habkost wrote: > > On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote: > >> From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > >> > >> Add PV_DEDICATED hint cpuid feature bit. > >> > > [...] > >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c > >> index d70954b..cf48931 100644 > >> --- a/target/i386/cpu.c > >> +++ b/target/i386/cpu.c > >> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu) > >> x86_cpu_get_supported_feature_word(w, false); > >> uint32_t requested_features = env->features[w]; > >> env->features[w] &= host_feat; > >> + if (cpu->pv_dedicated && (w == FEAT_KVM)) { > >> + env->features[w] |= CPUID_PV_DEDICATED; > >> + } > > > > Why do this trick here instead of just adding "pv-dedicated" to > > feature_word_info[FEAT_KVM].feat_names? > > I think because it can be added independent of KVM_GET_SUPPORTED_CPUID. If QEMU knows it can be enabled if outside GET_SUPPORTED_CPUID, kvm_arch_get_supported_cpuid() can return it as supported. -- Eduardo