On 01/02/2023 14.20, Pierre Morel wrote:
The KVM capability KVM_CAP_S390_CPU_TOPOLOGY is used to activate the S390_FEAT_CONFIGURATION_TOPOLOGY feature and the topology facility in the host CPU model 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@xxxxxxxxxxxxx> --- hw/s390x/cpu-topology.c | 2 +- target/s390x/cpu_models.c | 1 + target/s390x/kvm/kvm.c | 12 ++++++++++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c index 1028bf4476..c33378577b 100644 --- a/hw/s390x/cpu-topology.c +++ b/hw/s390x/cpu-topology.c @@ -55,7 +55,7 @@ int s390_socket_nb(S390CPU *cpu) */ 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 065ec6d66c..aca2c5c96b 100644 --- a/target/s390x/cpu_models.c +++ b/target/s390x/cpu_models.c @@ -254,6 +254,7 @@ 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..808e35a7bd 100644 --- a/target/s390x/kvm/kvm.c +++ b/target/s390x/kvm/kvm.c @@ -2470,6 +2470,18 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp) set_bit(S390_FEAT_UNPACK, model->features); }+ /*+ * If we have kernel support for CPU Topology indicate the + * configuration-topology facility. + */ + 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); + }
Not sure, but for the other capabilities, the kvm_vm_enable_cap() is rather done in kvm_arch_init() instead ... likely that it is properly available in case you don't run with the "host" cpu model? So should the kvm_vm_enable_cap(KVM_CAP_S390_CPU_TOPOLOGY) also be moved there (but of course keep the set_bit() here in kvm_s390_get_host_cpu_model())?
Thomas
