Re: [PATCH v4 3/4] KVM: s390: Add UV feature negotiation
From: Michael Mueller
Date: Thu Aug 17 2023 - 07:50:06 EST
On 15.08.23 17:14, Steffen Eiden wrote:
Add a uv_feature list for pv-guests to the KVM cpu-model.
The feature bits 'AP-interpretation for secure guests' and
'AP-interrupt for secure guests' are available.
Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Reviewed-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
but a minor comment, see below.
---
arch/s390/include/asm/kvm_host.h | 2 +
arch/s390/include/uapi/asm/kvm.h | 16 +++++++
arch/s390/kvm/kvm-s390.c | 73 ++++++++++++++++++++++++++++++++
3 files changed, 91 insertions(+)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 91bfecb91321..427f9528a7b6 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -817,6 +817,8 @@ struct kvm_s390_cpu_model {
__u64 *fac_list;
u64 cpuid;
unsigned short ibc;
+ /* subset of available UV-features for pv-guests enabled by user space */
+ struct kvm_s390_vm_cpu_uv_feat uv_feat_guest;
};
typedef int (*crypto_hook)(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index a73cf01a1606..abe926d43cbe 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -159,6 +159,22 @@ struct kvm_s390_vm_cpu_subfunc {
__u8 reserved[1728];
};
+#define KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST 6
+#define KVM_S390_VM_CPU_MACHINE_UV_FEAT_GUEST 7
+
+#define KVM_S390_VM_CPU_UV_FEAT_NR_BITS 64
+struct kvm_s390_vm_cpu_uv_feat {
+ union {
+ struct {
+ __u64 : 4;
+ __u64 ap : 1; /* bit 4 */
+ __u64 ap_intr : 1; /* bit 5 */
+ __u64 : 58;
+ };
+ __u64 feat;
+ };
+};
+
/* kvm attributes for crypto */
#define KVM_S390_VM_CRYPTO_ENABLE_AES_KW 0
#define KVM_S390_VM_CRYPTO_ENABLE_DEA_KW 1
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 813cc3d59c90..b3f17e014cab 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1531,6 +1531,39 @@ static int kvm_s390_set_processor_subfunc(struct kvm *kvm,
return 0;
}
+#define KVM_S390_VM_CPU_UV_FEAT_GUEST_MASK \
+( \
+ ((struct kvm_s390_vm_cpu_uv_feat){ \
+ .ap = 1, \
+ .ap_intr = 1, \
+ }) \
+ .feat \
+)
+
+static int kvm_s390_set_uv_feat(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_uv_feat __user *ptr = (void __user *)attr->addr;
+ unsigned long data, filter;
+
+ filter = uv_info.uv_feature_indications & KVM_S390_VM_CPU_UV_FEAT_GUEST_MASK;
if get_user() fails the uv feature bits in "filter" are
calculated in vain
+ if (get_user(data, &ptr->feat))
+ return -EFAULT;
could be done here, but that's really minor to me
+ if (!bitmap_subset(&data, &filter, KVM_S390_VM_CPU_UV_FEAT_NR_BITS))
+ return -EINVAL;
+
+ mutex_lock(&kvm->lock);
+ if (kvm->created_vcpus) {
+ mutex_unlock(&kvm->lock);
+ return -EBUSY;
+ }
+ kvm->arch.model.uv_feat_guest.feat = data;
+ mutex_unlock(&kvm->lock);
+
+ VM_EVENT(kvm, 3, "SET: guest UV-feat: 0x%16.16lx", data);
+
+ return 0;
+}
+
static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret = -ENXIO;
@@ -1545,6 +1578,9 @@ static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC:
ret = kvm_s390_set_processor_subfunc(kvm, attr);
break;
+ case KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST:
+ ret = kvm_s390_set_uv_feat(kvm, attr);
+ break;
}
return ret;
}
@@ -1777,6 +1813,33 @@ static int kvm_s390_get_machine_subfunc(struct kvm *kvm,
return 0;
}
+static int kvm_s390_get_processor_uv_feat(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_uv_feat __user *dst = (void __user *)attr->addr;
+ unsigned long feat = kvm->arch.model.uv_feat_guest.feat;
+
+ if (put_user(feat, &dst->feat))
+ return -EFAULT;
+ VM_EVENT(kvm, 3, "GET: guest UV-feat: 0x%16.16lx", feat);
+
+ return 0;
+}
+
+static int kvm_s390_get_machine_uv_feat(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+ struct kvm_s390_vm_cpu_uv_feat __user *dst = (void __user *)attr->addr;
+ unsigned long feat;
+
+ BUILD_BUG_ON(sizeof(*dst) != sizeof(uv_info.uv_feature_indications));
+
+ feat = uv_info.uv_feature_indications & KVM_S390_VM_CPU_UV_FEAT_GUEST_MASK;
+ if (put_user(feat, &dst->feat))
+ return -EFAULT;
+ VM_EVENT(kvm, 3, "GET: guest UV-feat: 0x%16.16lx", feat);
+
+ return 0;
+}
+
static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret = -ENXIO;
@@ -1800,6 +1863,12 @@ static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_CPU_MACHINE_SUBFUNC:
ret = kvm_s390_get_machine_subfunc(kvm, attr);
break;
+ case KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST:
+ ret = kvm_s390_get_processor_uv_feat(kvm, attr);
+ break;
+ case KVM_S390_VM_CPU_MACHINE_UV_FEAT_GUEST:
+ ret = kvm_s390_get_machine_uv_feat(kvm, attr);
+ break;
}
return ret;
}
@@ -1952,6 +2021,8 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_CPU_MACHINE_FEAT:
case KVM_S390_VM_CPU_MACHINE_SUBFUNC:
case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC:
+ case KVM_S390_VM_CPU_MACHINE_UV_FEAT_GUEST:
+ case KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST:
ret = 0;
break;
default:
@@ -3296,6 +3367,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.model.cpuid = kvm_s390_get_initial_cpuid();
kvm->arch.model.ibc = sclp.ibc & 0x0fff;
+ kvm->arch.model.uv_feat_guest.feat = 0;
+
kvm_s390_crypto_init(kvm);
if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)) {