Re: [PATCH v4] self_tests/kvm: sync_regs test for diag318

[Cornelia Huck <cohuck@redhat.com>]

On Mon,  7 Dec 2020 10:41:25 -0500
Collin Walling <walling@linux.ibm.com> wrote:

> The DIAGNOSE 0x0318 instruction, unique to s390x, is a privileged call
> that must be intercepted via SIE, handled in userspace, and the
> information set by the instruction is communicated back to KVM.
> 
> To test the instruction interception, an ad-hoc handler is defined which
> simply has a VM execute the instruction and then userspace will extract
> the necessary info. The handler is defined such that the instruction
> invocation occurs only once. It is up to the caller to determine how the
> info returned by this handler should be used.
> 
> The diag318 info is communicated from userspace to KVM via a sync_regs
> call. This is tested During a sync_regs test, where the diag318 info is

s/During/during/

> requested via the handler, then the info is stored in the appropriate
> register in KVM via a sync registers call.
> 
> If KVM does not support diag318, then the tests will print a message
> stating that diag318 was skipped, and the asserts will simply test
> against a value of 0.
> 
> Signed-off-by: Collin Walling <walling@linux.ibm.com>
> ---
>  tools/testing/selftests/kvm/Makefile          |  2 +-
>  .../kvm/include/s390x/diag318_test_handler.h  | 13 +++
>  .../kvm/lib/s390x/diag318_test_handler.c      | 82 +++++++++++++++++++
>  .../selftests/kvm/s390x/sync_regs_test.c      | 16 +++-
>  4 files changed, 111 insertions(+), 2 deletions(-)
>  create mode 100644 tools/testing/selftests/kvm/include/s390x/diag318_test_handler.h
>  create mode 100644 tools/testing/selftests/kvm/lib/s390x/diag318_test_handler.c

Looks reasonable to me.

Acked-by: Cornelia Huck <cohuck@redhat.com>