[PATCH v14 07/11] target/s390x/cpu topology: activating CPU topology

[Pierre Morel]

The KVM capability, KVM_CAP_S390_CPU_TOPOLOGY is used to
activate the S390_FEAT_CONFIGURATION_TOPOLOGY feature and
the topology facility for the guest in the case the topology
is available in QEMU and in KVM.

The feature is disabled by default and fenced for SE
(secure execution).

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 hw/s390x/cpu-topology.c   |  2 +-
 target/s390x/cpu_models.c |  1 +
 target/s390x/kvm/kvm.c    | 13 +++++++++++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index e6b4692581..b69955a1cd 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -52,7 +52,7 @@ static int s390_socket_nb(s390_topology_id id)
  */
 bool s390_has_topology(void)
 {
-    return false;
+    return s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY);
 }
 
 /**
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index c3a4f80633..3f05e05fd3 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -253,6 +253,7 @@ bool s390_has_feat(S390Feat feat)
         case S390_FEAT_SIE_CMMA:
         case S390_FEAT_SIE_PFMFI:
         case S390_FEAT_SIE_IBS:
+        case S390_FEAT_CONFIGURATION_TOPOLOGY:
             return false;
             break;
         default:
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index fb63be41b7..4e2a2ff516 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -2470,6 +2470,19 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
Error **errp)
         set_bit(S390_FEAT_UNPACK, model->features);
     }
 
+    /*
+     * If we have support for CPU Topology prevent overrule
+     * S390_FEAT_CONFIGURATION_TOPOLOGY with S390_FEAT_DISABLE_CPU_TOPOLOGY
+     * implemented in KVM, activate the CPU TOPOLOGY feature.
+     */
+    if (kvm_check_extension(kvm_state, KVM_CAP_S390_CPU_TOPOLOGY)) {
+        if (kvm_vm_enable_cap(kvm_state, KVM_CAP_S390_CPU_TOPOLOGY, 0) < 0) {
+            error_setg(errp, "KVM: Error enabling KVM_CAP_S390_CPU_TOPOLOGY");
+            return;
+        }
+        set_bit(S390_FEAT_CONFIGURATION_TOPOLOGY, model->features);
+    }
+
     /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
     set_bit(S390_FEAT_ZPCI, model->features);
     set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
-- 
2.31.1