From: Pierre Morel <pmorel@xxxxxxxxxxxxx> 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> Reviewed-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx> Message-Id: <20220714194334.127812-1-pmorel@xxxxxxxxxxxxx> Link: https://lore.kernel.org/all/20220714194334.127812-1-pmorel@xxxxxxxxxxxxx/ [frankja@xxxxxxxxxxxxx: Simple conflict resolution in Documentation/virt/kvm/api.rst] Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> --- Documentation/virt/kvm/api.rst | 25 ++++++++++++++++ arch/s390/include/uapi/asm/kvm.h | 1 + arch/s390/kvm/kvm-s390.c | 51 ++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 4 files changed, 78 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 5be5cc59869d..3c4551a2f6d0 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8269,6 +8269,31 @@ The capability has no effect if the nx_huge_pages module parameter is not set. This capability may only be set before any vCPUs are created. +8.39 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 or retrieved from. + 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..a73cf01a1606 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 diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 5d18b66a08c9..edfd4bbd0cba 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -642,6 +642,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_S390_ZPCI_OP: r = kvm_s390_pci_interp_allowed(); break; + case KVM_CAP_S390_CPU_TOPOLOGY: + r = test_facility(11); + break; default: r = 0; } @@ -853,6 +856,20 @@ 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: CAP_S390_CPU_TOPOLOGY %s", + r ? "(not available)" : "(success)"); + break; default: r = -EINVAL; break; @@ -1789,6 +1806,31 @@ static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val) read_unlock(&kvm->arch.sca_lock); } +static int kvm_s390_set_topo_change_indication(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_topo_change_indication(struct kvm *kvm, + struct kvm_device_attr *attr) +{ + u8 topo; + + if (!test_kvm_facility(kvm, 11)) + return -ENXIO; + + read_lock(&kvm->arch.sca_lock); + topo = ((struct bsca_block *)kvm->arch.sca)->utility.mtcr; + read_unlock(&kvm->arch.sca_lock); + + return put_user(topo, (u8 __user *)attr->addr); +} + static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr) { int ret; @@ -1809,6 +1851,9 @@ 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_topo_change_indication(kvm, attr); + break; default: ret = -ENXIO; break; @@ -1834,6 +1879,9 @@ 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_topo_change_indication(kvm, attr); + break; default: ret = -ENXIO; break; @@ -1907,6 +1955,9 @@ 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 20817dd7f2f1..7e06194129e3 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1168,6 +1168,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_X86_NOTIFY_VMEXIT 219 #define KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 220 #define KVM_CAP_S390_ZPCI_OP 221 +#define KVM_CAP_S390_CPU_TOPOLOGY 222 #ifdef KVM_CAP_IRQ_ROUTING -- 2.36.1
