| Message ID | 20210603114835.847451-6-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i386: KVM: expand Hyper-V features early | expand |
On Thu, Jun 03, 2021 at 01:48:31PM +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). > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > --- > target/i386/cpu.c | 4 ++++ > target/i386/kvm/kvm-stub.c | 5 +++++ > target/i386/kvm/kvm.c | 24 ++++++++++++++++++++---- > target/i386/kvm/kvm_i386.h | 1 + > 4 files changed, 30 insertions(+), 4 deletions(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index b2d8e5713911..159b7aa8f073 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5990,6 +5990,10 @@ 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..f6e7e4466e1a 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; > } > + > +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) > +{ > + abort(); > +} > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index a5f8553af921..650fdd970d6e 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -1217,13 +1217,22 @@ 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 bool hyperv_expand_features(CPUState *cs, Error **errp) > +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) > { > - X86CPU *cpu = X86_CPU(cs); > + CPUState *cs = CPU(cpu); > > if (!hyperv_enabled(cpu)) > return true; > > + /* > + * 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 true; > + > if (cpu->hyperv_passthrough) { > cpu->hyperv_vendor_id[0] = > hv_cpuid_get_host(cs, HV_CPUID_VENDOR_AND_MAX_FUNCTIONS, R_EBX); > @@ -1565,8 +1574,15 @@ int kvm_arch_init_vcpu(CPUState *cs) > > env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY; > > - /* Paravirtualization CPUIDs */ > - if (!hyperv_expand_features(cs, &local_err)) { > + /* > + * kvm_hyperv_expand_features() is called here for the second time in case > + * KVM_CAP_SYS_HYPERV_CPUID is not supported. While we can't possibly handle > + * 'query-cpu-model-expansion' in this case as we don't have a KVM vCPU to > + * check which Hyper-V enlightenments are supported and which are not, we > + * can still proceed and check/expand Hyper-V enlightenments here so legacy > + * behavior is preserved. > + */ Issue we might need to solve later: how can management software differentiate "Hyper-V enlightenments are not supported at all" from "we can't tell you which Hyper-V enlightenments are available because KVM_CAP_SYS_HYPERV_CPUID is unavailable"? > + if (!kvm_hyperv_expand_features(cpu, &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..54667b35f09c 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); > +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp); > > uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address); Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Eduardo Habkost <ehabkost@redhat.com> writes: > On Thu, Jun 03, 2021 at 01:48:31PM +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). >> >> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> >> --- >> target/i386/cpu.c | 4 ++++ >> target/i386/kvm/kvm-stub.c | 5 +++++ >> target/i386/kvm/kvm.c | 24 ++++++++++++++++++++---- >> target/i386/kvm/kvm_i386.h | 1 + >> 4 files changed, 30 insertions(+), 4 deletions(-) >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index b2d8e5713911..159b7aa8f073 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -5990,6 +5990,10 @@ 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..f6e7e4466e1a 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; >> } >> + >> +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) >> +{ >> + abort(); >> +} >> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c >> index a5f8553af921..650fdd970d6e 100644 >> --- a/target/i386/kvm/kvm.c >> +++ b/target/i386/kvm/kvm.c >> @@ -1217,13 +1217,22 @@ 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 bool hyperv_expand_features(CPUState *cs, Error **errp) >> +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) >> { >> - X86CPU *cpu = X86_CPU(cs); >> + CPUState *cs = CPU(cpu); >> >> if (!hyperv_enabled(cpu)) >> return true; >> >> + /* >> + * 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 true; >> + >> if (cpu->hyperv_passthrough) { >> cpu->hyperv_vendor_id[0] = >> hv_cpuid_get_host(cs, HV_CPUID_VENDOR_AND_MAX_FUNCTIONS, R_EBX); >> @@ -1565,8 +1574,15 @@ int kvm_arch_init_vcpu(CPUState *cs) >> >> env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY; >> >> - /* Paravirtualization CPUIDs */ >> - if (!hyperv_expand_features(cs, &local_err)) { >> + /* >> + * kvm_hyperv_expand_features() is called here for the second time in case >> + * KVM_CAP_SYS_HYPERV_CPUID is not supported. While we can't possibly handle >> + * 'query-cpu-model-expansion' in this case as we don't have a KVM vCPU to >> + * check which Hyper-V enlightenments are supported and which are not, we >> + * can still proceed and check/expand Hyper-V enlightenments here so legacy >> + * behavior is preserved. >> + */ > > Issue we might need to solve later: how can management software > differentiate "Hyper-V enlightenments are not supported at all" > from "we can't tell you which Hyper-V enlightenments are > available because KVM_CAP_SYS_HYPERV_CPUID is unavailable"? > In case we're not considering *very* old kernels, basic Hyper-V enlightenments should always be available so if 'query-cpu-model-expansion' doesn't give you anything (like now, pre-patch) then you treat this as 'QEMU can't tell me what's supported' and not like 'no Hyper-V enlightenments at all'. > >> + if (!kvm_hyperv_expand_features(cpu, &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..54667b35f09c 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); >> +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp); >> >> uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address); > > Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Thanks!
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index b2d8e5713911..159b7aa8f073 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -5990,6 +5990,10 @@ 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..f6e7e4466e1a 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; } + +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) +{ + abort(); +} diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index a5f8553af921..650fdd970d6e 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -1217,13 +1217,22 @@ 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 bool hyperv_expand_features(CPUState *cs, Error **errp) +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) { - X86CPU *cpu = X86_CPU(cs); + CPUState *cs = CPU(cpu); if (!hyperv_enabled(cpu)) return true; + /* + * 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 true; + if (cpu->hyperv_passthrough) { cpu->hyperv_vendor_id[0] = hv_cpuid_get_host(cs, HV_CPUID_VENDOR_AND_MAX_FUNCTIONS, R_EBX); @@ -1565,8 +1574,15 @@ int kvm_arch_init_vcpu(CPUState *cs) env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY; - /* Paravirtualization CPUIDs */ - if (!hyperv_expand_features(cs, &local_err)) { + /* + * kvm_hyperv_expand_features() is called here for the second time in case + * KVM_CAP_SYS_HYPERV_CPUID is not supported. While we can't possibly handle + * 'query-cpu-model-expansion' in this case as we don't have a KVM vCPU to + * check which Hyper-V enlightenments are supported and which are not, we + * can still proceed and check/expand Hyper-V enlightenments here so legacy + * behavior is preserved. + */ + if (!kvm_hyperv_expand_features(cpu, &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..54667b35f09c 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); +bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp); uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address);
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 <vkuznets@redhat.com> --- target/i386/cpu.c | 4 ++++ target/i386/kvm/kvm-stub.c | 5 +++++ target/i386/kvm/kvm.c | 24 ++++++++++++++++++++---- target/i386/kvm/kvm_i386.h | 1 + 4 files changed, 30 insertions(+), 4 deletions(-)