selftests: kvm: s390: Add s390x ucontrol test suite with hpage test

selftests: kvm: s390: Add s390x ucontrol test suite with hpage test

Add test suite to validate the s390x architecture specific ucontrol KVM
interface.

Make use of the selftest test harness.

* uc_cap_hpage testcase verifies that a ucontrol VM cannot be run with
  hugepages.

To allow testing of the ucontrol interface the kernel needs a
non-default config containing CONFIG_KVM_S390_UCONTROL.
This config needs to be set to built-in (y) as this cannot be built as
module.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20240807154512.316936-4-schlameuss@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20240807154512.316936-4-schlameuss@linux.ibm.com>