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>

1 files changed, 58 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c1fcb7a3c125..0d7fc66289a0 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2762,6 +2762,64 @@ register number to be used.
 The "reserved" field is meant for future extensions. It is not used by
 KVM with the currently defined set of flags.
 
+4.90 KVM_S390_GET_SKEYS
+
+Capability: KVM_CAP_S390_SKEYS
+Architectures: s390
+Type: vm ioctl
+Parameters: struct kvm_s390_skeys
+Returns: 0 on success, KVM_S390_GET_KEYS_NONE if guest is not using storage
+         keys, negative value on error
+
+This ioctl is used to get guest storage key values on the s390
+architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
+
+struct kvm_s390_skeys {
+	__u64 start_gfn;
+	__u64 count;
+	__u64 skeydata_addr;
+	__u32 flags;
+	__u32 reserved[9];
+};
+
+The start_gfn field is the number of the first guest frame whose storage keys
+you want to get.
+
+The count field is the number of consecutive frames (starting from start_gfn)
+whose storage keys to get. The count field must be at least 1 and the maximum
+allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
+will cause the ioctl to return -EINVAL.
+
+The skeydata_addr field is the address to a buffer large enough to hold count
+bytes. This buffer will be filled with storage key data by the ioctl.
+
+4.91 KVM_S390_SET_SKEYS
+
+Capability: KVM_CAP_S390_SKEYS
+Architectures: s390
+Type: vm ioctl
+Parameters: struct kvm_s390_skeys
+Returns: 0 on success, negative value on error
+
+This ioctl is used to set guest storage key values on the s390
+architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
+See section on KVM_S390_GET_SKEYS for struct definition.
+
+The start_gfn field is the number of the first guest frame whose storage keys
+you want to set.
+
+The count field is the number of consecutive frames (starting from start_gfn)
+whose storage keys to get. The count field must be at least 1 and the maximum
+allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
+will cause the ioctl to return -EINVAL.
+
+The skeydata_addr field is the address to a buffer containing count bytes of
+storage keys. Each byte in the buffer will be set as the storage key for a
+single frame starting at start_gfn for count frames.
+
+Note: If any architecturally invalid key value is found in the given data then
+the ioctl will return -EINVAL.
+
 5. The kvm_run structure
 ------------------------