This property will contain all the features that were removed from the CPU because they are not supported by the host. This way, libvirt or other management tools can emulate the check/enforce behavior by checking if filtered-properties is all zeroes, before starting the guest. Example output where some features were missing: $ ./install/bin/qemu-system-x86_64 -enable-kvm -cpu Haswell,check -S -qmp unix:/tmp/m,server,nowait warning: host doesn't support requested feature: CPUID.01H:ECX.fma [bit 12] warning: host doesn't support requested feature: CPUID.01H:ECX.movbe [bit 22] warning: host doesn't support requested feature: CPUID.01H:ECX.tsc-deadline [bit 24] warning: host doesn't support requested feature: CPUID.01H:ECX.xsave [bit 26] warning: host doesn't support requested feature: CPUID.01H:ECX.avx [bit 28] warning: host doesn't support requested feature: CPUID.07H:EBX.fsgsbase [bit 0] warning: host doesn't support requested feature: CPUID.07H:EBX.bmi1 [bit 3] warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4] warning: host doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5] warning: host doesn't support requested feature: CPUID.07H:EBX.smep [bit 7] warning: host doesn't support requested feature: CPUID.07H:EBX.bmi2 [bit 8] warning: host doesn't support requested feature: CPUID.07H:EBX.erms [bit 9] warning: host doesn't support requested feature: CPUID.07H:EBX.invpcid [bit 10] warning: host doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11] [...] $ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1] --property=filtered-features item[0].cpuid-register: EDX item[0].cpuid-input-eax: 2147483658 item[0].features: 0 item[1].cpuid-register: EAX item[1].cpuid-input-eax: 1073741825 item[1].features: 0 item[2].cpuid-register: EDX item[2].cpuid-input-eax: 3221225473 item[2].features: 0 item[3].cpuid-register: ECX item[3].cpuid-input-eax: 2147483649 item[3].features: 0 item[4].cpuid-register: EDX item[4].cpuid-input-eax: 2147483649 item[4].features: 0 item[5].cpuid-register: EBX item[5].cpuid-input-eax: 7 item[5].features: 4025 item[5].cpuid-input-ecx: 0 item[6].cpuid-register: ECX item[6].cpuid-input-eax: 1 item[6].features: 356519936 item[7].cpuid-register: EDX item[7].cpuid-input-eax: 1 item[7].features: 0 Example output when no feature is missing: $ ./install/bin/qemu-system-x86_64 -enable-kvm -cpu Nehalem,enforce -S -qmp unix:/tmp/m,server,nowait [...] $ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1] --property=filtered-features item[0].cpuid-register: EDX item[0].cpuid-input-eax: 2147483658 item[0].features: 0 item[1].cpuid-register: EAX item[1].cpuid-input-eax: 1073741825 item[1].features: 0 item[2].cpuid-register: EDX item[2].cpuid-input-eax: 3221225473 item[2].features: 0 item[3].cpuid-register: ECX item[3].cpuid-input-eax: 2147483649 item[3].features: 0 item[4].cpuid-register: EDX item[4].cpuid-input-eax: 2147483649 item[4].features: 0 item[5].cpuid-register: EBX item[5].cpuid-input-eax: 7 item[5].features: 0 item[5].cpuid-input-ecx: 0 item[6].cpuid-register: ECX item[6].cpuid-input-eax: 1 item[6].features: 0 item[7].cpuid-register: EDX item[7].cpuid-input-eax: 1 item[7].features: 0 Signed-off-by: Eduardo Habkost <ehabkost@xxxxxxxxxx> --- target-i386/cpu.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 64e5570..0dceaf2 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -1372,11 +1372,11 @@ static void x86_cpuid_set_tsc_freq(Object *obj, Visitor *v, void *opaque, cpu->env.tsc_khz = value / 1000; } +/* Generic getter for "feature-words" and "filtered-features" properties */ static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque, const char *name, Error **errp) { - X86CPU *cpu = X86_CPU(obj); - CPUX86State *env = &cpu->env; + uint32_t *array = (uint32_t *)opaque; FeatureWord w; Error *err = NULL; X86CPUFeatureWordInfo word_infos[FEATURE_WORDS] = { }; @@ -1390,7 +1390,7 @@ static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque, qwi->has_cpuid_input_ecx = wi->cpuid_needs_ecx; qwi->cpuid_input_ecx = wi->cpuid_ecx; qwi->cpuid_register = x86_reg_info_32[wi->cpuid_reg].qapi_enum; - qwi->features = env->features[w]; + qwi->features = array[w]; /* List will be in reverse order, but order shouldn't matter */ list_entries[w].next = list; @@ -2354,7 +2354,10 @@ static void x86_cpu_initfn(Object *obj) x86_cpuid_set_tsc_freq, NULL, NULL, NULL); object_property_add(obj, "feature-words", "X86CPUFeatureWordInfo", x86_cpu_get_feature_words, - NULL, NULL, NULL, NULL); + NULL, NULL, (void *)env->features, NULL); + object_property_add(obj, "filtered-features", "X86CPUFeatureWordInfo", + x86_cpu_get_feature_words, + NULL, NULL, (void *)cpu->filtered_features, NULL); env->cpuid_apic_id = x86_cpu_apic_id_from_index(cs->cpu_index); -- 1.8.1.4 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list