| Message ID | 20220701162559.158313-4-pmorel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: KVM: CPU Topology | expand |
On 7/1/22 18:25, Pierre Morel wrote: > During a subsystem reset the Topology-Change-Report is cleared. > > Let's give userland the possibility to clear the MTCR in the case > of a subsystem reset. > > To migrate the MTCR, we give userland the possibility to > query the MTCR state. > > We indicate KVM support for the CPU topology facility with a new > KVM capability: KVM_CAP_S390_CPU_TOPOLOGY. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > Documentation/virt/kvm/api.rst | 25 +++++++++++++++ > arch/s390/include/uapi/asm/kvm.h | 10 ++++++ > arch/s390/kvm/kvm-s390.c | 53 ++++++++++++++++++++++++++++++++ > include/uapi/linux/kvm.h | 1 + > 4 files changed, 89 insertions(+) > > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst > index 11e00a46c610..5e086125d8ad 100644 > --- a/Documentation/virt/kvm/api.rst > +++ b/Documentation/virt/kvm/api.rst > @@ -7956,6 +7956,31 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. > When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of > type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. > > +8.37 KVM_CAP_S390_CPU_TOPOLOGY > +------------------------------ > + > +:Capability: KVM_CAP_S390_CPU_TOPOLOGY > +:Architectures: s390 > +:Type: vm > + > +This capability indicates that KVM will provide the S390 CPU Topology > +facility which consist of the interpretation of the PTF instruction for > +the function code 2 along with interception and forwarding of both the > +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) > +instruction to the userland hypervisor. The latter only if the user STSI capability is also enabled. > + > +The stfle facility 11, CPU Topology facility, should not be indicated > +to the guest without this capability. > + > +When this capability is present, KVM provides a new attribute group > +on vm fd, KVM_S390_VM_CPU_TOPOLOGY. > +This new attribute allows to get, set or clear the Modified Change > +Topology Report (MTCR) bit of the SCA through the kvm_device_attr > +structure. > + > +When getting the Modified Change Topology Report value, the attr->addr > +must point to a byte where the value will be stored. > + > 9. Known KVM API problems > ========================= > > diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h > index 7a6b14874d65..df5e8279ffd0 100644 > --- a/arch/s390/include/uapi/asm/kvm.h > +++ b/arch/s390/include/uapi/asm/kvm.h > @@ -74,6 +74,7 @@ struct kvm_s390_io_adapter_req { > #define KVM_S390_VM_CRYPTO 2 > #define KVM_S390_VM_CPU_MODEL 3 > #define KVM_S390_VM_MIGRATION 4 > +#define KVM_S390_VM_CPU_TOPOLOGY 5 > > /* kvm attributes for mem_ctrl */ > #define KVM_S390_VM_MEM_ENABLE_CMMA 0 > @@ -171,6 +172,15 @@ struct kvm_s390_vm_cpu_subfunc { > #define KVM_S390_VM_MIGRATION_START 1 > #define KVM_S390_VM_MIGRATION_STATUS 2 > > +/* kvm attributes for cpu topology */ > +#define KVM_S390_VM_CPU_TOPO_MTCR_CLEAR 0 > +#define KVM_S390_VM_CPU_TOPO_MTCR_SET 1 > + > +struct kvm_cpu_topology { > + __u16 mtcr : 1; > + __u16 reserved : 15; > +}; This is no longer used, is it? > + > /* for KVM_GET_REGS and KVM_SET_REGS */ > struct kvm_regs { > /* general purpose regs for s390 */ > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index ee59b03f2e45..5029fe40adbd 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -606,6 +606,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_S390_PROTECTED: > r = is_prot_virt_host(); > break; > + case KVM_CAP_S390_CPU_TOPOLOGY: > + r = test_facility(11); > + break; > default: > r = 0; > } > @@ -817,6 +820,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) > icpt_operexc_on_all_vcpus(kvm); > r = 0; > break; > + case KVM_CAP_S390_CPU_TOPOLOGY: > + r = -EINVAL; > + mutex_lock(&kvm->lock); > + if (kvm->created_vcpus) { > + r = -EBUSY; > + } else if (test_facility(11)) { > + set_kvm_facility(kvm->arch.model.fac_mask, 11); > + set_kvm_facility(kvm->arch.model.fac_list, 11); > + r = 0; > + } > + mutex_unlock(&kvm->lock); > + VM_EVENT(kvm, 3, "ENABLE: CPU TOPOLOGY %s", I still would go for consistency here, "ENABLE: CAP_S390_CPU_TOPOLOGY %s". > + r ? "(not available)" : "(success)"); > + break; > default: > r = -EINVAL; > break; > @@ -1716,6 +1733,33 @@ static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val) > read_unlock(&kvm->arch.sca_lock); > } > > +static int kvm_s390_set_topology(struct kvm *kvm, struct kvm_device_attr *attr) > +{ > + if (!test_kvm_facility(kvm, 11)) > + return -ENXIO; > + > + kvm_s390_update_topology_change_report(kvm, !!attr->attr); Will this not be automatically clamped to 0,1 if the argument has type bool? > + return 0; > +} > + > +static int kvm_s390_get_topology(struct kvm *kvm, struct kvm_device_attr *attr) > +{ > + union sca_utility utility; > + struct bsca_block *sca = kvm->arch.sca; > + __u8 topo; > + > + if (!test_kvm_facility(kvm, 11)) > + return -ENXIO; > + read_lock(&kvm->arch.sca_lock); utility.val = READ_ONCE(kvm->arch.sca->utility.val); read_unlock(&kvm->arch.sca_lock); And then get rid of the sca declaration. > + topo = utility.mtcr; > + > + if (copy_to_user((void __user *)attr->addr, &topo, sizeof(topo))) > + return -EFAULT; > + > + return 0; > +} > + [...]
On 7/4/22 11:35, Janis Schoetterl-Glausch wrote: > On 7/1/22 18:25, Pierre Morel wrote: >> During a subsystem reset the Topology-Change-Report is cleared. >> >> Let's give userland the possibility to clear the MTCR in the case >> of a subsystem reset. >> >> To migrate the MTCR, we give userland the possibility to >> query the MTCR state. >> >> We indicate KVM support for the CPU topology facility with a new >> KVM capability: KVM_CAP_S390_CPU_TOPOLOGY. >> >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >> --- >> Documentation/virt/kvm/api.rst | 25 +++++++++++++++ >> arch/s390/include/uapi/asm/kvm.h | 10 ++++++ >> arch/s390/kvm/kvm-s390.c | 53 ++++++++++++++++++++++++++++++++ >> include/uapi/linux/kvm.h | 1 + >> 4 files changed, 89 insertions(+) >> >> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >> index 11e00a46c610..5e086125d8ad 100644 >> --- a/Documentation/virt/kvm/api.rst >> +++ b/Documentation/virt/kvm/api.rst >> @@ -7956,6 +7956,31 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. >> When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of >> type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. >> >> +8.37 KVM_CAP_S390_CPU_TOPOLOGY >> +------------------------------ >> + >> +:Capability: KVM_CAP_S390_CPU_TOPOLOGY >> +:Architectures: s390 >> +:Type: vm >> + >> +This capability indicates that KVM will provide the S390 CPU Topology >> +facility which consist of the interpretation of the PTF instruction for >> +the function code 2 along with interception and forwarding of both the >> +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) >> +instruction to the userland hypervisor. > The latter only if the user STSI capability is also enabled. Hum, not sure about this. we can not set facility 11 and return 3 to STSI(15) for valid selectors. I think that it was right before, KVM_CAP_S390_CPU_TOPOLOGY and KVM_CAP_S390_USER_STSI are independent in KVM, userland can turn on one and not the other. But KVM proposes both. Of course it is stupid to turn on only KVM_CAP_S390_CPU_TOPOLOGY but KVM is not responsible for this userland is. Otherwise, we need to check on KVM_CAP_S390_USER_STSI before authorizing KVM_CAP_S390_CPU_TOPOLOGY and that looks even more complicated for me, or we suppress the KVM_CAP_S390_CPU_TOPOLOGY and implement the all stsi(15) in the kernel what I really do not think is good because of the complexity of the userland API >> + >> +The stfle facility 11, CPU Topology facility, should not be indicated >> +to the guest without this capability. >> + >> +When this capability is present, KVM provides a new attribute group >> +on vm fd, KVM_S390_VM_CPU_TOPOLOGY. >> +This new attribute allows to get, set or clear the Modified Change >> +Topology Report (MTCR) bit of the SCA through the kvm_device_attr >> +structure. >> + >> +When getting the Modified Change Topology Report value, the attr->addr >> +must point to a byte where the value will be stored. >> + >> 9. Known KVM API problems >> ========================= >> >> diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h >> index 7a6b14874d65..df5e8279ffd0 100644 >> --- a/arch/s390/include/uapi/asm/kvm.h >> +++ b/arch/s390/include/uapi/asm/kvm.h >> @@ -74,6 +74,7 @@ struct kvm_s390_io_adapter_req { >> #define KVM_S390_VM_CRYPTO 2 >> #define KVM_S390_VM_CPU_MODEL 3 >> #define KVM_S390_VM_MIGRATION 4 >> +#define KVM_S390_VM_CPU_TOPOLOGY 5 >> >> /* kvm attributes for mem_ctrl */ >> #define KVM_S390_VM_MEM_ENABLE_CMMA 0 >> @@ -171,6 +172,15 @@ struct kvm_s390_vm_cpu_subfunc { >> #define KVM_S390_VM_MIGRATION_START 1 >> #define KVM_S390_VM_MIGRATION_STATUS 2 >> >> +/* kvm attributes for cpu topology */ >> +#define KVM_S390_VM_CPU_TOPO_MTCR_CLEAR 0 >> +#define KVM_S390_VM_CPU_TOPO_MTCR_SET 1 >> + >> +struct kvm_cpu_topology { >> + __u16 mtcr : 1; >> + __u16 reserved : 15; >> +}; > > This is no longer used, is it? No, I sent the wrong patch it seems!! Sorry for that. There is nothing more in kvm.h now but the definition for KVM_S390_VM_CPU_TOPOLOGY >> + >> /* for KVM_GET_REGS and KVM_SET_REGS */ >> struct kvm_regs { >> /* general purpose regs for s390 */ >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index ee59b03f2e45..5029fe40adbd 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -606,6 +606,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> case KVM_CAP_S390_PROTECTED: >> r = is_prot_virt_host(); >> break; >> + case KVM_CAP_S390_CPU_TOPOLOGY: >> + r = test_facility(11); >> + break; >> default: >> r = 0; >> } >> @@ -817,6 +820,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) >> icpt_operexc_on_all_vcpus(kvm); >> r = 0; >> break; >> + case KVM_CAP_S390_CPU_TOPOLOGY: >> + r = -EINVAL; >> + mutex_lock(&kvm->lock); >> + if (kvm->created_vcpus) { >> + r = -EBUSY; >> + } else if (test_facility(11)) { >> + set_kvm_facility(kvm->arch.model.fac_mask, 11); >> + set_kvm_facility(kvm->arch.model.fac_list, 11); >> + r = 0; >> + } >> + mutex_unlock(&kvm->lock); >> + VM_EVENT(kvm, 3, "ENABLE: CPU TOPOLOGY %s", > > I still would go for consistency here, "ENABLE: CAP_S390_CPU_TOPOLOGY %s". Yes, done. > >> + r ? "(not available)" : "(success)"); >> + break; >> default: >> r = -EINVAL; >> break; >> @@ -1716,6 +1733,33 @@ static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val) >> read_unlock(&kvm->arch.sca_lock); >> } >> >> +static int kvm_s390_set_topology(struct kvm *kvm, struct kvm_device_attr *attr) >> +{ >> + if (!test_kvm_facility(kvm, 11)) >> + return -ENXIO; >> + >> + kvm_s390_update_topology_change_report(kvm, !!attr->attr); > > Will this not be automatically clamped to 0,1 if the argument has type bool? I do not know, anyway done like this is sure. >> + return 0; >> +} >> + >> +static int kvm_s390_get_topology(struct kvm *kvm, struct kvm_device_attr *attr) >> +{ >> + union sca_utility utility; >> + struct bsca_block *sca = kvm->arch.sca; >> + __u8 topo; >> + >> + if (!test_kvm_facility(kvm, 11)) >> + return -ENXIO; >> + > read_lock(&kvm->arch.sca_lock); > utility.val = READ_ONCE(kvm->arch.sca->utility.val); > read_unlock(&kvm->arch.sca_lock); > > And then get rid of the sca declaration. OK >> + topo = utility.mtcr; >> + >> + if (copy_to_user((void __user *)attr->addr, &topo, sizeof(topo))) >> + return -EFAULT; >> + >> + return 0; >> +} >> + > [...] >
On 7/4/22 15:56, Pierre Morel wrote: > > > On 7/4/22 11:35, Janis Schoetterl-Glausch wrote: >> On 7/1/22 18:25, Pierre Morel wrote: >>> During a subsystem reset the Topology-Change-Report is cleared. >>> >>> Let's give userland the possibility to clear the MTCR in the case >>> of a subsystem reset. >>> >>> To migrate the MTCR, we give userland the possibility to >>> query the MTCR state. >>> >>> We indicate KVM support for the CPU topology facility with a new >>> KVM capability: KVM_CAP_S390_CPU_TOPOLOGY. >>> >>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >>> --- >>> Documentation/virt/kvm/api.rst | 25 +++++++++++++++ >>> arch/s390/include/uapi/asm/kvm.h | 10 ++++++ >>> arch/s390/kvm/kvm-s390.c | 53 ++++++++++++++++++++++++++++++++ >>> include/uapi/linux/kvm.h | 1 + >>> 4 files changed, 89 insertions(+) >>> >>> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >>> index 11e00a46c610..5e086125d8ad 100644 >>> --- a/Documentation/virt/kvm/api.rst >>> +++ b/Documentation/virt/kvm/api.rst >>> @@ -7956,6 +7956,31 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. >>> When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of >>> type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. >>> +8.37 KVM_CAP_S390_CPU_TOPOLOGY >>> +------------------------------ >>> + >>> +:Capability: KVM_CAP_S390_CPU_TOPOLOGY >>> +:Architectures: s390 >>> +:Type: vm >>> + >>> +This capability indicates that KVM will provide the S390 CPU Topology >>> +facility which consist of the interpretation of the PTF instruction for >>> +the function code 2 along with interception and forwarding of both the >>> +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) >>> +instruction to the userland hypervisor. >> The latter only if the user STSI capability is also enabled. > > Hum, not sure about this. > we can not set facility 11 and return 3 to STSI(15) for valid selectors. I think the PoP allows for this: When the specified function-code, selector-1, and selector-2 combination is invalid (is other than as shown in Figure 10-84), or if it is valid but the requested information is not available because the specified level does not implement or does not fully implement the instruction or because a necessary part of the level is uninstalled or not initialized, and provided that an exception is not recognized (see “Special Conditions”), the condition code is set to 3. When the function code is nonzero, the combination is valid, the requested information is available, and there is no exception, the requested information is stored in a system-information block (SYSIB) at the second-operand address. So if user_stsi is off the information is not available because the level does not fully implement the instruction. But I'm fine with KVM_CAP_S390_CPU_TOPOLOGY implying KVM_CAP_S390_USER_STSI, too. > > I think that it was right before, KVM_CAP_S390_CPU_TOPOLOGY and KVM_CAP_S390_USER_STSI are independent in KVM, userland can turn on one and not the other. > But KVM proposes both. > > Of course it is stupid to turn on only KVM_CAP_S390_CPU_TOPOLOGY but KVM is not responsible for this userland is. > > Otherwise, we need to check on KVM_CAP_S390_USER_STSI before authorizing KVM_CAP_S390_CPU_TOPOLOGY and that looks even more complicated for me, > or we suppress the KVM_CAP_S390_CPU_TOPOLOGY and implement the all stsi(15) in the kernel what I really do not think is good because of the complexity of the userland API [...]
On 7/5/22 10:09, Janis Schoetterl-Glausch wrote: > On 7/4/22 15:56, Pierre Morel wrote: >> >> >> On 7/4/22 11:35, Janis Schoetterl-Glausch wrote: >>> On 7/1/22 18:25, Pierre Morel wrote: >>>> During a subsystem reset the Topology-Change-Report is cleared. >>>> >>>> Let's give userland the possibility to clear the MTCR in the case >>>> of a subsystem reset. >>>> >>>> To migrate the MTCR, we give userland the possibility to >>>> query the MTCR state. >>>> >>>> We indicate KVM support for the CPU topology facility with a new >>>> KVM capability: KVM_CAP_S390_CPU_TOPOLOGY. >>>> >>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >>>> --- >>>> Documentation/virt/kvm/api.rst | 25 +++++++++++++++ >>>> arch/s390/include/uapi/asm/kvm.h | 10 ++++++ >>>> arch/s390/kvm/kvm-s390.c | 53 ++++++++++++++++++++++++++++++++ >>>> include/uapi/linux/kvm.h | 1 + >>>> 4 files changed, 89 insertions(+) >>>> >>>> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >>>> index 11e00a46c610..5e086125d8ad 100644 >>>> --- a/Documentation/virt/kvm/api.rst >>>> +++ b/Documentation/virt/kvm/api.rst >>>> @@ -7956,6 +7956,31 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. >>>> When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of >>>> type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. >>>> +8.37 KVM_CAP_S390_CPU_TOPOLOGY >>>> +------------------------------ >>>> + >>>> +:Capability: KVM_CAP_S390_CPU_TOPOLOGY >>>> +:Architectures: s390 >>>> +:Type: vm >>>> + >>>> +This capability indicates that KVM will provide the S390 CPU Topology >>>> +facility which consist of the interpretation of the PTF instruction for >>>> +the function code 2 along with interception and forwarding of both the >>>> +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) >>>> +instruction to the userland hypervisor. >>> The latter only if the user STSI capability is also enabled. >> >> Hum, not sure about this. >> we can not set facility 11 and return 3 to STSI(15) for valid selectors. > > I think the PoP allows for this: > > When the specified function-code, selector-1, and > selector-2 combination is invalid (is other than as > shown in Figure 10-84), > or if it is valid but the > requested information is not available because the > specified level does not implement or does not fully > implement the instruction or because a necessary > part of the level is uninstalled or not initialized, and > provided that an exception is not recognized (see > “Special Conditions”), the condition code is set to 3. > When the function code is nonzero, the combination > is valid, the requested information is available, and > there is no exception, the requested information is > stored in a system-information block (SYSIB) at the > second-operand address. > > So if user_stsi is off the information is not available because the level does not fully implement the instruction. > But I'm fine with KVM_CAP_S390_CPU_TOPOLOGY implying KVM_CAP_S390_USER_STSI, too. OK, I do like you say, return CC3 if no user_stsi is available Thanks, Pierre > >> >> I think that it was right before, KVM_CAP_S390_CPU_TOPOLOGY and KVM_CAP_S390_USER_STSI are independent in KVM, userland can turn on one and not the other. >> But KVM proposes both. >> >> Of course it is stupid to turn on only KVM_CAP_S390_CPU_TOPOLOGY but KVM is not responsible for this userland is. >> >> Otherwise, we need to check on KVM_CAP_S390_USER_STSI before authorizing KVM_CAP_S390_CPU_TOPOLOGY and that looks even more complicated for me, >> or we suppress the KVM_CAP_S390_CPU_TOPOLOGY and implement the all stsi(15) in the kernel what I really do not think is good because of the complexity of the userland API > > [...] >
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 11e00a46c610..5e086125d8ad 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7956,6 +7956,31 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. +8.37 KVM_CAP_S390_CPU_TOPOLOGY +------------------------------ + +:Capability: KVM_CAP_S390_CPU_TOPOLOGY +:Architectures: s390 +:Type: vm + +This capability indicates that KVM will provide the S390 CPU Topology +facility which consist of the interpretation of the PTF instruction for +the function code 2 along with interception and forwarding of both the +PTF instruction with function codes 0 or 1 and the STSI(15,1,x) +instruction to the userland hypervisor. + +The stfle facility 11, CPU Topology facility, should not be indicated +to the guest without this capability. + +When this capability is present, KVM provides a new attribute group +on vm fd, KVM_S390_VM_CPU_TOPOLOGY. +This new attribute allows to get, set or clear the Modified Change +Topology Report (MTCR) bit of the SCA through the kvm_device_attr +structure. + +When getting the Modified Change Topology Report value, the attr->addr +must point to a byte where the value will be stored. + 9. Known KVM API problems ========================= diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h index 7a6b14874d65..df5e8279ffd0 100644 --- a/arch/s390/include/uapi/asm/kvm.h +++ b/arch/s390/include/uapi/asm/kvm.h @@ -74,6 +74,7 @@ struct kvm_s390_io_adapter_req { #define KVM_S390_VM_CRYPTO 2 #define KVM_S390_VM_CPU_MODEL 3 #define KVM_S390_VM_MIGRATION 4 +#define KVM_S390_VM_CPU_TOPOLOGY 5 /* kvm attributes for mem_ctrl */ #define KVM_S390_VM_MEM_ENABLE_CMMA 0 @@ -171,6 +172,15 @@ struct kvm_s390_vm_cpu_subfunc { #define KVM_S390_VM_MIGRATION_START 1 #define KVM_S390_VM_MIGRATION_STATUS 2 +/* kvm attributes for cpu topology */ +#define KVM_S390_VM_CPU_TOPO_MTCR_CLEAR 0 +#define KVM_S390_VM_CPU_TOPO_MTCR_SET 1 + +struct kvm_cpu_topology { + __u16 mtcr : 1; + __u16 reserved : 15; +}; + /* for KVM_GET_REGS and KVM_SET_REGS */ struct kvm_regs { /* general purpose regs for s390 */ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ee59b03f2e45..5029fe40adbd 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -606,6 +606,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_S390_PROTECTED: r = is_prot_virt_host(); break; + case KVM_CAP_S390_CPU_TOPOLOGY: + r = test_facility(11); + break; default: r = 0; } @@ -817,6 +820,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) icpt_operexc_on_all_vcpus(kvm); r = 0; break; + case KVM_CAP_S390_CPU_TOPOLOGY: + r = -EINVAL; + mutex_lock(&kvm->lock); + if (kvm->created_vcpus) { + r = -EBUSY; + } else if (test_facility(11)) { + set_kvm_facility(kvm->arch.model.fac_mask, 11); + set_kvm_facility(kvm->arch.model.fac_list, 11); + r = 0; + } + mutex_unlock(&kvm->lock); + VM_EVENT(kvm, 3, "ENABLE: CPU TOPOLOGY %s", + r ? "(not available)" : "(success)"); + break; default: r = -EINVAL; break; @@ -1716,6 +1733,33 @@ static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val) read_unlock(&kvm->arch.sca_lock); } +static int kvm_s390_set_topology(struct kvm *kvm, struct kvm_device_attr *attr) +{ + if (!test_kvm_facility(kvm, 11)) + return -ENXIO; + + kvm_s390_update_topology_change_report(kvm, !!attr->attr); + return 0; +} + +static int kvm_s390_get_topology(struct kvm *kvm, struct kvm_device_attr *attr) +{ + union sca_utility utility; + struct bsca_block *sca = kvm->arch.sca; + __u8 topo; + + if (!test_kvm_facility(kvm, 11)) + return -ENXIO; + + utility.val = READ_ONCE(sca->utility.val); + topo = utility.mtcr; + + if (copy_to_user((void __user *)attr->addr, &topo, sizeof(topo))) + return -EFAULT; + + return 0; +} + static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr) { int ret; @@ -1736,6 +1780,9 @@ static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_MIGRATION: ret = kvm_s390_vm_set_migration(kvm, attr); break; + case KVM_S390_VM_CPU_TOPOLOGY: + ret = kvm_s390_set_topology(kvm, attr); + break; default: ret = -ENXIO; break; @@ -1761,6 +1808,9 @@ static int kvm_s390_vm_get_attr(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_MIGRATION: ret = kvm_s390_vm_get_migration(kvm, attr); break; + case KVM_S390_VM_CPU_TOPOLOGY: + ret = kvm_s390_get_topology(kvm, attr); + break; default: ret = -ENXIO; break; @@ -1834,6 +1884,9 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_MIGRATION: ret = 0; break; + case KVM_S390_VM_CPU_TOPOLOGY: + ret = test_kvm_facility(kvm, 11) ? 0 : -ENXIO; + break; default: ret = -ENXIO; break; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 5088bd9f1922..33317d820032 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1157,6 +1157,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_VM_TSC_CONTROL 214 #define KVM_CAP_SYSTEM_EVENT_DATA 215 #define KVM_CAP_ARM_SYSTEM_SUSPEND 216 +#define KVM_CAP_S390_CPU_TOPOLOGY 217 #ifdef KVM_CAP_IRQ_ROUTING
During a subsystem reset the Topology-Change-Report is cleared. Let's give userland the possibility to clear the MTCR in the case of a subsystem reset. To migrate the MTCR, we give userland the possibility to query the MTCR state. We indicate KVM support for the CPU topology facility with a new KVM capability: KVM_CAP_S390_CPU_TOPOLOGY. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- Documentation/virt/kvm/api.rst | 25 +++++++++++++++ arch/s390/include/uapi/asm/kvm.h | 10 ++++++ arch/s390/kvm/kvm-s390.c | 53 ++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 4 files changed, 89 insertions(+)