s390/uvdevice: Add 'Lock Secret Store' UVC

Userspace can call the Lock Secret Store Ultravisor Call
using IOCTLs on the uvdevice. The Lock Secret Store UV call
disables all additions of secrets for the future.

The uvdevice is merely transporting the request from userspace to the
Ultravisor.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230615100533.3996107-6-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20230615100533.3996107-6-seiden@linux.ibm.com>

s390/uvdevice: Add 'List Secrets' UVC

Userspace can call the List Secrets Ultravisor Call
using IOCTLs on the uvdevice. The List Secrets UV call lists the
identifier of the secrets in the UV secret store.

The uvdevice is merely transporting the request from userspace to
Ultravisor. It's neither checking nor manipulating the request or
response data.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230615100533.3996107-5-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20230615100533.3996107-5-seiden@linux.ibm.com>

s390/uvdevice: Add 'Add Secret' UVC

Userspace can call the Add Secret Ultravisor Call using IOCTLs on the
uvdevice. The Add Secret UV call sends an encrypted and
cryptographically verified request to the Ultravisor. The request
inserts a protected guest's secret into the Ultravisor for later use.

The uvdevice is merely transporting the request from userspace to the
Ultravisor. It's neither checking nor manipulating the request data.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230615100533.3996107-4-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20230615100533.3996107-4-seiden@linux.ibm.com>

s390/uvdevice: Add info IOCTL

Add an IOCTL that allows userspace to find out which IOCTLs the uvdevice
supports without trial and error.

Explicitly expose the IOCTL nr for the request types.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230615100533.3996107-3-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20230615100533.3996107-3-seiden@linux.ibm.com>

drivers/s390/char: Add Ultravisor io device

This patch adds a new miscdevice to expose some Ultravisor functions
to userspace. Userspace can send IOCTLs to the uvdevice that will then
emit a corresponding Ultravisor Call and hands the result over to
userspace. The uvdevice is available if the Ultravisor Call facility is
present.
Userspace can call the Retrieve Attestation Measurement
Ultravisor Call using IOCTLs on the uvdevice.

The uvdevice will do some sanity checks first.
Then, copy the request data to kernel space, build the UVCB,
perform the UV call, and copy the result back to userspace.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/kvm/20220516113335.338212-1-seiden@linux.ibm.com/
Message-Id: <20220516113335.338212-1-seiden@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com> (whitespace and tristate fixes, pick)