From: Pierre Morel <pmorel@linux.ibm.com>
Date: Thu, 14 Jul 2022 21:43:34 +0200
Subject: KVM: s390: resetting the Topology-Change-Report
Git-commit: f5ecfee94493475783074e86ded10a0499d779fc
Patch-mainline: v6.0-rc1
References: jsc#PED-593
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>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20220714194334.127812-1-pmorel@linux.ibm.com>
Link: https://lore.kernel.org/all/20220714194334.127812-1-pmorel@linux.ibm.com/
[frankja@linux.ibm.com: Simple conflict resolution in Documentation/virt/kvm/api.rst]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
[mkoutny: Adjust context for users/jroedel variant]
---
Documentation/virt/kvm/api.rst | 24 ++++++++++++++++++
arch/s390/include/uapi/asm/kvm.h | 1
arch/s390/kvm/kvm-s390.c | 51 +++++++++++++++++++++++++++++++++++++++
include/uapi/linux/kvm.h | 1
4 files changed, 77 insertions(+)
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -7537,4 +7537,28 @@ PV guests. The `KVM_PV_DUMP` command is
dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is
available and supports the `KVM_PV_DUMP_CPU` subcommand.
+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.
--- 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
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -644,6 +644,9 @@ int kvm_vm_ioctl_check_extension(struct
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;
}
@@ -855,6 +858,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *
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;
@@ -1796,6 +1813,31 @@ static void kvm_s390_update_topology_cha
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;
@@ -1816,6 +1858,9 @@ static int kvm_s390_vm_set_attr(struct k
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;
@@ -1841,6 +1886,9 @@ static int kvm_s390_vm_get_attr(struct k
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;
@@ -1914,6 +1962,9 @@ static int kvm_s390_vm_has_attr(struct k
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;
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1122,6 +1122,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_S390_MEM_OP_EXTENSION 211
#define KVM_CAP_S390_PROTECTED_DUMP 217
#define KVM_CAP_S390_ZPCI_OP 221
+#define KVM_CAP_S390_CPU_TOPOLOGY 222
#ifdef KVM_CAP_IRQ_ROUTING