Eduardo Habkost <[email protected]> writes: > On Fri, Sep 04, 2020 at 04:54:31PM +0200, Vitaly Kuznetsov wrote: >> To make Hyper-V features appear in e.g. QMP query-cpu-model-expansion we >> need to expand and set the corresponding CPUID leaves early. Modify >> x86_cpu_get_supported_feature_word() to call newly intoduced Hyper-V >> specific kvm_hv_get_supported_cpuid() instead of >> kvm_arch_get_supported_cpuid(). We can't use kvm_arch_get_supported_cpuid() >> as Hyper-V specific CPUID leaves intersect with KVM's. >> >> Note, early expansion will only happen when KVM supports system wide >> KVM_GET_SUPPORTED_HV_CPUID ioctl (KVM_CAP_SYS_HYPERV_CPUID). > > Will this implicitly enable hyperv CPUID passthrough when using > "-cpu host"? Do we want it to? >
I hope it won't. With 'hv_*' features set explicitly we will get just them (if the host supports), with 'hv_passthrough' we will get everything supported by the host. With no 'hv_*' parameters on the command line we should get no Hyper-V features. I'll check this. Personally, I don't think '-host' mode should enable any Hyper-V features as these features have side-effects. E.g. if you enable SynIC you won't be able to use vAPIC. Probably not a reasonable default for the majority of the guests which (hopefully) are Linux. >> >> Signed-off-by: Vitaly Kuznetsov <[email protected]> >> --- >> target/i386/cpu.c | 15 +++++++++------ >> target/i386/kvm.c | 15 +++++++++++++++ >> target/i386/kvm_i386.h | 7 +++++++ >> 3 files changed, 31 insertions(+), 6 deletions(-) >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index 479c4bbbf459..d3c4ecb3535c 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -5147,7 +5147,7 @@ CpuDefinitionInfoList *qmp_query_cpu_definitions(Error >> **errp) >> return cpu_list; >> } >> >> -static uint64_t x86_cpu_get_supported_feature_word(FeatureWord w, >> +static uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord >> w, >> bool migratable_only) >> { >> FeatureWordInfo *wi = &feature_word_info[w]; >> @@ -5156,9 +5156,12 @@ static uint64_t >> x86_cpu_get_supported_feature_word(FeatureWord w, >> if (kvm_enabled()) { >> switch (wi->type) { >> case CPUID_FEATURE_WORD: >> - r = kvm_arch_get_supported_cpuid(kvm_state, wi->cpuid.eax, >> - wi->cpuid.ecx, >> - wi->cpuid.reg); >> + if (hyperv_feature_word(w)) >> + r = kvm_hv_get_supported_cpuid(cpu, w); >> + else >> + r = kvm_arch_get_supported_cpuid(kvm_state, wi->cpuid.eax, >> + wi->cpuid.ecx, >> + wi->cpuid.reg); >> break; >> case MSR_FEATURE_WORD: >> r = kvm_arch_get_supported_msr_feature(kvm_state, >> @@ -6485,7 +6488,7 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error >> **errp) >> * by the user. >> */ >> env->features[w] |= >> - x86_cpu_get_supported_feature_word(w, cpu->migratable) & >> + x86_cpu_get_supported_feature_word(cpu, w, cpu->migratable) >> & >> ~env->user_features[w] & >> ~feature_word_info[w].no_autoenable_flags; >> } >> @@ -6589,7 +6592,7 @@ static void x86_cpu_filter_features(X86CPU *cpu, bool >> verbose) >> >> for (w = 0; w < FEATURE_WORDS; w++) { >> uint64_t host_feat = >> - x86_cpu_get_supported_feature_word(w, false); >> + x86_cpu_get_supported_feature_word(cpu, w, false); >> uint64_t requested_features = env->features[w]; >> uint64_t unavailable_features = requested_features & ~host_feat; >> mark_unavailable_features(cpu, w, unavailable_features, prefix); >> diff --git a/target/i386/kvm.c b/target/i386/kvm.c >> index 961241528a5c..764b96fbbb7d 100644 >> --- a/target/i386/kvm.c >> +++ b/target/i386/kvm.c >> @@ -1449,6 +1449,21 @@ static int hyperv_fill_cpuids(CPUState *cs, >> return cpuid_i; >> } >> >> +uint32_t kvm_hv_get_supported_cpuid(X86CPU *cpu, enum FeatureWord w) >> +{ >> + CPUState *cs = CPU(cpu); >> + CPUX86State *env = &cpu->env; >> + Error *local_err = NULL; >> + >> + hyperv_expand_features(cs, &local_err); >> + >> + if (local_err) { >> + error_report_err(local_err); >> + } >> + >> + return env->features[w]; >> +} >> + >> static Error *hv_passthrough_mig_blocker; >> static Error *hv_no_nonarch_cs_mig_blocker; >> >> diff --git a/target/i386/kvm_i386.h b/target/i386/kvm_i386.h >> index 064b8798a26c..2e7da4f39668 100644 >> --- a/target/i386/kvm_i386.h >> +++ b/target/i386/kvm_i386.h >> @@ -48,4 +48,11 @@ bool kvm_has_waitpkg(void); >> >> bool kvm_hv_vpindex_settable(void); >> >> +static inline bool hyperv_feature_word(enum FeatureWord w) >> +{ >> + return w >= FEAT_HYPERV_EAX && w <= FEAT_HV_NESTED_EDX; >> +} >> + >> +uint32_t kvm_hv_get_supported_cpuid(X86CPU *cpu, enum FeatureWord w); >> + >> #endif >> -- >> 2.25.4 >> -- Vitaly
