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@xxxxxxxxxxxxx> --- 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 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 -- 2.31.1