Re: [PATCH v4 1/1] s390x: KVM: accept STSI for CPU topology information

From: David Hildenbrand
Date: Thu Sep 16 2021 - 10:03:53 EST


struct kvm_vm_stat {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 51d1594bd6cd..f3887e13c5db 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -608,6 +608,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_S390_PROTECTED:
r = is_prot_virt_host();
break;
+ case KVM_CAP_S390_CPU_TOPOLOGY:
+ r = test_facility(11);
+ break;
default:
r = 0;
}
@@ -819,6 +822,19 @@ 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:

As given in my example, this should be

r = -EINVAL;
mutex_lock(&kvm->lock);
if (kvm->created_vcpus) {
r = -EBUSY;
} else if (test_facility(11)) {
...
}

Similar to how we handle KVM_CAP_S390_VECTOR_REGISTERS.

[...]

+
+ /* PTF needs both host and guest facilities to enable interpretation */
+ if (test_kvm_facility(vcpu->kvm, 11) && test_facility(11))
+ vcpu->arch.sie_block->ecb |= ECB_PTF;

This should be simplified to

if (test_kvm_facility(vcpu->kvm, 11))

then. (vsie code below is correct)


--
Thanks,

David / dhildenb