diff options
| author | Pierre Morel <pmorel@linux.ibm.com> | 2022-07-14 12:18:23 +0200 |
|---|---|---|
| committer | Janosch Frank <frankja@linux.ibm.com> | 2022-07-20 10:57:36 +0200 |
| commit | 24fe0195bc19306b2769b43b3e22bd35bd6fb061 (patch) | |
| tree | 11defb5fa0332ff31d98b40e37f21cc20a0a48c6 /arch/s390/kvm/kvm-s390.c | |
| parent | 0130337ec45bffd26ba3e782850da3b68f1eef9d (diff) | |
KVM: s390: guest support for topology function
We report a topology change to the guest for any CPU hotplug.
The reporting to the guest is done using the Multiprocessor
Topology-Change-Report (MTCR) bit of the utility entry in the guest's
SCA which will be cleared during the interpretation of PTF.
On every vCPU creation we set the MCTR bit to let the guest know the
next time it uses the PTF with command 2 instruction that the
topology changed and that it should use the STSI(15.1.x) instruction
to get the topology details.
STSI(15.1.x) gives information on the CPU configuration topology.
Let's accept the interception of STSI with the function code 15 and
let the userland part of the hypervisor handle it when userland
supports the CPU Topology facility.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20220714101824.101601-2-pmorel@linux.ibm.com
Message-Id: <20220714101824.101601-2-pmorel@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 5b77c43fbb01..5d18b66a08c9 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1763,6 +1763,32 @@ static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr) return ret; } +/** + * kvm_s390_update_topology_change_report - update CPU topology change report + * @kvm: guest KVM description + * @val: set or clear the MTCR bit + * + * Updates the Multiprocessor Topology-Change-Report bit to signal + * the guest with a topology change. + * This is only relevant if the topology facility is present. + * + * The SCA version, bsca or esca, doesn't matter as offset is the same. + */ +static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val) +{ + union sca_utility new, old; + struct bsca_block *sca; + + read_lock(&kvm->arch.sca_lock); + sca = kvm->arch.sca; + do { + old = READ_ONCE(sca->utility); + new = old; + new.mtcr = val; + } while (cmpxchg(&sca->utility.val, old.val, new.val) != old.val); + read_unlock(&kvm->arch.sca_lock); +} + static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr) { int ret; @@ -3172,6 +3198,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) kvm_clear_async_pf_completion_queue(vcpu); if (!kvm_is_ucontrol(vcpu->kvm)) sca_del_vcpu(vcpu); + kvm_s390_update_topology_change_report(vcpu->kvm, 1); if (kvm_is_ucontrol(vcpu->kvm)) gmap_remove(vcpu->arch.gmap); @@ -3574,6 +3601,8 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu) vcpu->arch.sie_block->ecb |= ECB_HOSTPROTINT; if (test_kvm_facility(vcpu->kvm, 9)) vcpu->arch.sie_block->ecb |= ECB_SRSI; + if (test_kvm_facility(vcpu->kvm, 11)) + vcpu->arch.sie_block->ecb |= ECB_PTF; if (test_kvm_facility(vcpu->kvm, 73)) vcpu->arch.sie_block->ecb |= ECB_TE; if (!kvm_is_ucontrol(vcpu->kvm)) @@ -3707,6 +3736,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) rc = kvm_s390_vcpu_setup(vcpu); if (rc) goto out_ucontrol_uninit; + + kvm_s390_update_topology_change_report(vcpu->kvm, 1); return 0; out_ucontrol_uninit: |