Eduardo Habkost <ehabk...@redhat.com> writes: > On Thu, Apr 22, 2021 at 06:11:26PM +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). >> >> Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> >> --- >> target/i386/cpu.c | 4 ++++ >> target/i386/kvm/kvm-stub.c | 5 +++++ >> target/i386/kvm/kvm.c | 15 ++++++++++++--- >> target/i386/kvm/kvm_i386.h | 1 + >> 4 files changed, 22 insertions(+), 3 deletions(-) >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index d72b8760e7a3..18b57f3d8b9c 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -6514,6 +6514,10 @@ static void x86_cpu_expand_features(X86CPU *cpu, >> Error **errp) >> if (env->cpuid_xlevel2 == UINT32_MAX) { >> env->cpuid_xlevel2 = env->cpuid_min_xlevel2; >> } >> + >> + if (kvm_enabled()) { >> + kvm_hyperv_expand_features(cpu, errp); >> + } >> } >> >> /* >> diff --git a/target/i386/kvm/kvm-stub.c b/target/i386/kvm/kvm-stub.c >> index 92f49121b8fa..7f175faa3abd 100644 >> --- a/target/i386/kvm/kvm-stub.c >> +++ b/target/i386/kvm/kvm-stub.c >> @@ -39,3 +39,8 @@ bool kvm_hv_vpindex_settable(void) >> { >> return false; >> } >> + >> +void kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) >> +{ >> + return; > > Maybe we should make it abort()? This function should never be > called if KVM is disabled. >
Sure, can do that. >> +} >> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c >> index a42263b24fca..d5551c4ab5cf 100644 >> --- a/target/i386/kvm/kvm.c >> +++ b/target/i386/kvm/kvm.c >> @@ -1216,13 +1216,22 @@ static uint32_t hv_build_cpuid_leaf(CPUState *cs, >> uint32_t func, int reg) >> * of 'hv_passthrough' mode and fills the environment with all supported >> * Hyper-V features. >> */ >> -static void hyperv_expand_features(CPUState *cs, Error **errp) >> +void kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) >> { >> - X86CPU *cpu = X86_CPU(cs); >> + CPUState *cs = CPU(cpu); >> >> if (!hyperv_enabled(cpu)) >> return; >> >> + /* >> + * When kvm_hyperv_expand_features is called at CPU feature expansion >> + * time per-CPU kvm_state is not available yet so we can only proceed >> + * when KVM_CAP_SYS_HYPERV_CPUID is supported. >> + */ >> + if (!cs->kvm_state && >> + !kvm_check_extension(kvm_state, KVM_CAP_SYS_HYPERV_CPUID)) >> + return; >> + >> if (cpu->hyperv_passthrough) { >> cpu->hyperv_vendor_id[0] = >> hv_cpuid_get_host(cs, HV_CPUID_VENDOR_AND_MAX_FUNCTIONS, R_EBX); >> @@ -1556,7 +1565,7 @@ int kvm_arch_init_vcpu(CPUState *cs) >> env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY; >> >> /* Paravirtualization CPUIDs */ >> - hyperv_expand_features(cs, &local_err); >> + kvm_hyperv_expand_features(cpu, &local_err); > > Do we still need to call the function again here? > > If the first expansion isn't expanding everything, I'm afraid > this second call will hide bugs in query-cpu-model-expansion. > The first expansion will do nothing if KVM_CAP_SYS_HYPERV_CPUID is not supported, calling it here allows us to proceed. The series makes 'query-cpu-model-expansion' output correct only with KVM_CAP_SYS_HYPERV_CPUID, without it we don't seem to be able to do much (unless we decide to create a 'scratch' CPU or something like that). > >> if (local_err) { >> error_report_err(local_err); >> return -ENOSYS; >> diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h >> index dc725083891c..f1176491051d 100644 >> --- a/target/i386/kvm/kvm_i386.h >> +++ b/target/i386/kvm/kvm_i386.h >> @@ -47,6 +47,7 @@ bool kvm_has_x2apic_api(void); >> bool kvm_has_waitpkg(void); >> >> bool kvm_hv_vpindex_settable(void); >> +void kvm_hyperv_expand_features(X86CPU *cpu, Error **errp); >> >> uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address); >> >> -- >> 2.30.2 >> -- Vitaly