[PATCH v2 00/10] selftests: kvm: s390: Add s390x ucontrol selftests

Christoph Schlameuss
2024-07-23T09:32:10Z

This patch series adds a selftest suite to validate the s390x
architecture specific ucontrol KVM interface.

When creating a VM on s390x it is possible to create it as userspace
controlled VM or in short ucontrol VM.
These VMs delegates the management of the VM to userspace instead
of handling most events within the kernel. Consequently the userspace
has to manage interrupts, memory allocation etc.

Before this patch set this functionality lacks any public test cases.
It is desirable to add test cases for this interface to be able to
reduce the risk of breaking changes in the future.

In order to provision a ucontrol VM the kernel needs to be compiled with
the CONFIG_KVM_S390_UCONTROL enabled. The users with sys_admin capability
can then create a new ucontrol VM providing the KVM_VM_S390_UCONTROL
parameter to the KVM_CREATE_VM ioctl.

The kernels existing selftest helper functions can only be partially be
reused for these tests.

The test cases cover existing special handling of ucontrol VMs within the
implementation and basic VM creation and handling cases:
* Reject setting HPAGE when VM is ucontrol
* Assert KVM_GET_DIRTY_LOG is rejected
* Assert KVM_S390_VM_MEM_LIMIT_SIZE is rejected
* Assert state of initial SIE flags setup by the kernel
* Run simple program in VM with and without DAT
* Assert KVM_EXIT_S390_UCONTROL exit on not mapped memory access
* Assert functionality of storage keys in ucontrol VM

Running the test cases requires sys_admin capabilities to start the
ucontrol VM.
This can be achieved by running as root or with a command like:

sudo setpriv --reuid nobody --inh-caps -all,+sys_admin \
--ambient-caps -all,+sys_admin --bounding-set -all,+sys_admin \
./ucontrol_test

The patch set does also contain some code cleanup / consolidation of
architecture specific defines that are now used in multiple test cases.

---

V1 -> V2:
- add ucontrol to s390 debug config (new patch)
- PATCH 2: changed atomic_t to __u32 (thanks Claudio)
- PATCH 4: reformatted comment in FIXTURE_SETUP(uc_kvm)
- PATCH 5: refactored to display 8 byte blocks + more internal reuse
(thanks Claudio)
- PATCH 7: make use of more declarative defines instead of magic values
- PATCH 8: make use of more declarative defines instead of magic values
(thanks Claudio)
- PATCH 9: add reference to fix verified by the test case

Christoph Schlameuss (10):
selftests: kvm: s390: Define page sizes in shared header
selftests: kvm: s390: Add kvm_s390_sie_block definition for userspace
tests
selftests: kvm: s390: Add s390x ucontrol test suite with hpage test
selftests: kvm: s390: Add test fixture and simple VM setup tests
selftests: kvm: s390: Add debug print functions
selftests: kvm: s390: Add VM run test case
selftests: kvm: s390: Add uc_map_unmap VM test case
selftests: kvm: s390: Add uc_skey VM test case
selftests: kvm: s390: Verify reject memory region operations for
ucontrol VMs
s390: Enable KVM_S390_UCONTROL config in debug_defconfig

arch/s390/Kconfig.debug | 3 +
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/s390x/debug_print.h | 69 ++
.../selftests/kvm/include/s390x/processor.h | 5 +
.../testing/selftests/kvm/include/s390x/sie.h | 240 +++++++
.../selftests/kvm/lib/s390x/processor.c | 10 +-
tools/testing/selftests/kvm/s390x/cmma_test.c | 7 +-
tools/testing/selftests/kvm/s390x/config | 2 +
.../testing/selftests/kvm/s390x/debug_test.c | 4 +-
tools/testing/selftests/kvm/s390x/memop.c | 4 +-
tools/testing/selftests/kvm/s390x/tprot.c | 5 +-
.../selftests/kvm/s390x/ucontrol_test.c | 614 ++++++++++++++++++
13 files changed, 949 insertions(+), 16 deletions(-)
create mode 100644 tools/testing/selftests/kvm/include/s390x/debug_print.h
create mode 100644 tools/testing/selftests/kvm/include/s390x/sie.h
create mode 100644 tools/testing/selftests/kvm/s390x/config
create mode 100644 tools/testing/selftests/kvm/s390x/ucontrol_test.c

base-commit: 66ebbdfdeb093e097399b1883390079cd4c3022b
--
2.45.2