| Message ID | 20210422161130.652779-16-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i386: KVM: expand Hyper-V features early | expand |
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 <vkuznets@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. > +} > 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. > 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 >
Eduardo Habkost <ehabkost@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 <vkuznets@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 >>
On Mon, May 24, 2021 at 02:13:09PM +0200, Vitaly Kuznetsov wrote: [...] > >> 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). Oh, I see. I suggest adding a comment explaining that. Developers might be tempted to delete it and not notice it breaks under older kernels.
Eduardo Habkost <ehabkost@redhat.com> writes: > On Mon, May 24, 2021 at 02:13:09PM +0200, Vitaly Kuznetsov wrote: > [...] >> >> 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). > > Oh, I see. I suggest adding a comment explaining that. > Developers might be tempted to delete it and not notice it breaks > under older kernels. Will do, thanks!
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; +} 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); 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);
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 | 15 ++++++++++++--- target/i386/kvm/kvm_i386.h | 1 + 4 files changed, 22 insertions(+), 3 deletions(-)