On 21.02.19 19:43, Christian Borntraeger wrote:
> While we will not implement interception for query functions yet, we can
> and should disable functions that have a control bit based on the given
> CPU model.
>
> Let us start with enabling the subfunction interface.
>
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/kvm-s390.c | 34 +++++++++++++++++++++-----------
> 2 files changed, 23 insertions(+), 12 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index d5d24889c3bcf..a042861554507 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -712,6 +712,7 @@ struct s390_io_adapter {
> struct kvm_s390_cpu_model {
> /* facility mask supported by kvm & hosting machine */
> __u64 fac_mask[S390_ARCH_FAC_LIST_SIZE_U64];
> + struct kvm_s390_vm_cpu_subfunc subfuncs;
> /* facility list requested by guest (in dma page) */
> __u64 *fac_list;
> u64 cpuid;
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 7f4bc58a53b97..5058fe58ece77 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -1258,11 +1258,20 @@ static int kvm_s390_set_processor_feat(struct kvm *kvm,
> static int kvm_s390_set_processor_subfunc(struct kvm *kvm,
> struct kvm_device_attr *attr)
> {
> - /*
> - * Once supported by kernel + hw, we have to store the subfunctions
> - * in kvm->arch and remember that user space configured them.
> - */
> - return -ENXIO;
> + mutex_lock(&kvm->lock);
> + if (kvm->created_vcpus) {
> + mutex_unlock(&kvm->lock);
> + return -EBUSY;
> + }
> +
> + if (copy_from_user(&kvm->arch.model.subfuncs, (void __user *)attr->addr,
> + sizeof(struct kvm_s390_vm_cpu_subfunc))) {
> + mutex_unlock(&kvm->lock);
> + return -EFAULT;
> + }
Wonder if we want to allow setting features the host does not have. I
guess we want to (similar to stfle).
> + mutex_unlock(&kvm->lock);
> +
> + return 0;
> }
>
> static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
> @@ -1381,12 +1390,11 @@ static int kvm_s390_get_machine_feat(struct kvm *kvm,
> static int kvm_s390_get_processor_subfunc(struct kvm *kvm,
> struct kvm_device_attr *attr)
> {
> - /*
> - * Once we can actually configure subfunctions (kernel + hw support),
> - * we have to check if they were already set by user space, if so copy
> - * them from kvm->arch.
> - */
> - return -ENXIO;
> + if (copy_to_user((void __user *)attr->addr, &kvm->arch.model.subfuncs,
> + sizeof(struct kvm_s390_vm_cpu_subfunc)))
> + return -EFAULT;
> +
> + return 0;
> }
>
> static int kvm_s390_get_machine_subfunc(struct kvm *kvm,
> @@ -1397,6 +1405,7 @@ static int kvm_s390_get_machine_subfunc(struct kvm *kvm,
> return -EFAULT;
> return 0;
> }
> +
> static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
> {
> int ret = -ENXIO;
> @@ -1514,10 +1523,10 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
> case KVM_S390_VM_CPU_PROCESSOR_FEAT:
> case KVM_S390_VM_CPU_MACHINE_FEAT:
> case KVM_S390_VM_CPU_MACHINE_SUBFUNC:
> + case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC:
> ret = 0;
> break;
> /* configuring subfunctions is not supported yet */
You want to drop that comment as well I think.
> - case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC:
> default:
> ret = -ENXIO;
> break;
> @@ -2218,6 +2227,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> kvm->arch.model.fac_list[i] = S390_lowcore.stfle_fac_list[i] &
> kvm_s390_fac_base[i];
> }
> + kvm->arch.model.subfuncs = kvm_s390_available_subfunc;
>
> /* we are always in czam mode - even on pre z14 machines */
> set_kvm_facility(kvm->arch.model.fac_mask, 138);
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
