KVM: s390: Create ioctl for Getting/Setting guest storage keys
Provide the KVM_S390_GET_SKEYS and KVM_S390_SET_SKEYS ioctl which can be used
to get/set guest storage keys. This functionality is needed for live migration
of s390 guests that use storage keys.
Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index fdfa106..0dc22ba 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -179,6 +179,7 @@
case KVM_CAP_MP_STATE:
case KVM_CAP_S390_USER_SIGP:
case KVM_CAP_S390_USER_STSI:
+ case KVM_CAP_S390_SKEYS:
r = 1;
break;
case KVM_CAP_S390_MEM_OP:
@@ -729,6 +730,108 @@
return ret;
}
+static long kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
+{
+ uint8_t *keys;
+ uint64_t hva;
+ unsigned long curkey;
+ int i, r = 0;
+
+ if (args->flags != 0)
+ return -EINVAL;
+
+ /* Is this guest using storage keys? */
+ if (!mm_use_skey(current->mm))
+ return KVM_S390_GET_SKEYS_NONE;
+
+ /* Enforce sane limit on memory allocation */
+ if (args->count < 1 || args->count > KVM_S390_SKEYS_MAX)
+ return -EINVAL;
+
+ keys = kmalloc_array(args->count, sizeof(uint8_t),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!keys)
+ keys = vmalloc(sizeof(uint8_t) * args->count);
+ if (!keys)
+ return -ENOMEM;
+
+ for (i = 0; i < args->count; i++) {
+ hva = gfn_to_hva(kvm, args->start_gfn + i);
+ if (kvm_is_error_hva(hva)) {
+ r = -EFAULT;
+ goto out;
+ }
+
+ curkey = get_guest_storage_key(current->mm, hva);
+ if (IS_ERR_VALUE(curkey)) {
+ r = curkey;
+ goto out;
+ }
+ keys[i] = curkey;
+ }
+
+ r = copy_to_user((uint8_t __user *)args->skeydata_addr, keys,
+ sizeof(uint8_t) * args->count);
+ if (r)
+ r = -EFAULT;
+out:
+ kvfree(keys);
+ return r;
+}
+
+static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
+{
+ uint8_t *keys;
+ uint64_t hva;
+ int i, r = 0;
+
+ if (args->flags != 0)
+ return -EINVAL;
+
+ /* Enforce sane limit on memory allocation */
+ if (args->count < 1 || args->count > KVM_S390_SKEYS_MAX)
+ return -EINVAL;
+
+ keys = kmalloc_array(args->count, sizeof(uint8_t),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!keys)
+ keys = vmalloc(sizeof(uint8_t) * args->count);
+ if (!keys)
+ return -ENOMEM;
+
+ r = copy_from_user(keys, (uint8_t __user *)args->skeydata_addr,
+ sizeof(uint8_t) * args->count);
+ if (r) {
+ r = -EFAULT;
+ goto out;
+ }
+
+ /* Enable storage key handling for the guest */
+ s390_enable_skey();
+
+ for (i = 0; i < args->count; i++) {
+ hva = gfn_to_hva(kvm, args->start_gfn + i);
+ if (kvm_is_error_hva(hva)) {
+ r = -EFAULT;
+ goto out;
+ }
+
+ /* Lowest order bit is reserved */
+ if (keys[i] & 0x01) {
+ r = -EINVAL;
+ goto out;
+ }
+
+ r = set_guest_storage_key(current->mm, hva,
+ (unsigned long)keys[i], 0);
+ if (r)
+ goto out;
+ }
+out:
+ kvfree(keys);
+ return r;
+}
+
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -788,6 +891,26 @@
r = kvm_s390_vm_has_attr(kvm, &attr);
break;
}
+ case KVM_S390_GET_SKEYS: {
+ struct kvm_s390_skeys args;
+
+ r = -EFAULT;
+ if (copy_from_user(&args, argp,
+ sizeof(struct kvm_s390_skeys)))
+ break;
+ r = kvm_s390_get_skeys(kvm, &args);
+ break;
+ }
+ case KVM_S390_SET_SKEYS: {
+ struct kvm_s390_skeys args;
+
+ r = -EFAULT;
+ if (copy_from_user(&args, argp,
+ sizeof(struct kvm_s390_skeys)))
+ break;
+ r = kvm_s390_set_skeys(kvm, &args);
+ break;
+ }
default:
r = -ENOTTY;
}