Re: [PATCH v2 5/5] KVM: s390: selftests: Add regression tests for PLO subfunctions

Christoph Schlameuss
2024-08-21T07:25:46Z

On Tue Aug 20, 2024 at 8:48 AM CEST, Hariharan Mari wrote:
> Extend the existing regression test framework for s390x CPU subfunctions
> to include tests for the Perform Locked Operation (PLO) subfunction
> functions.
>
> PLO was introduced in the very first 64-bit machine generation.
> Hence it is assumed PLO is always installed in the Z Arch.
> The test procedure follows the established pattern.
>
> Suggested-by: Janosch Frank <frankja@linux.ibm.com>
> Signed-off-by: Hariharan Mari <hari55@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

LGTM (apart from the accidental whitespace)

Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>

> ---
> .../kvm/s390x/cpumodel_subfuncs_test.c | 34 +++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c b/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> index c31f445c6f03..255984a52365 100644
> --- a/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> +++ b/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> @@ -20,6 +20,8 @@
>
> #include "kvm_util.h"
>
> +#define U8_MAX ((u8)~0U)
> +
> /**
> * Query available CPU subfunctions
> */
> @@ -37,6 +39,33 @@ static void get_cpu_machine_subfuntions(struct kvm_vm *vm,
> TEST_ASSERT(!r, "Get cpu subfunctions failed r=%d errno=%d", r, errno);
> }
>
> +static inline int plo_test_bit(unsigned char nr)
> +{
> + unsigned long function = (unsigned long)nr | 0x100;
> + int cc;
> +
> + asm volatile(" lgr 0,%[function]\n"
> + /* Parameter registers are ignored for "test bit" */
> + " plo 0,0,0,0(0)\n"
> + " ipm %0\n"
> + " srl %0,28\n"
> + : "=d" (cc)
> + : [function] "d" (function)
> + : "cc", "0");
> + return cc == 0;
> +}
> +
> +/*
> + * Testing Perform Locked Operation (PLO) CPU subfunction's ASM block
> + */
> +static void test_plo_asm_block(u8 (*query)[32])
> +{
> + for (int i = 0; i <= U8_MAX; ++i) {
> + if (plo_test_bit(i))
> + (*query)[i >> 3] |= 0x80 >> (i & 7);
> + }
> +}
> +
> /*
> * Testing Crypto Compute Message Authentication Code (KMAC) CPU subfunction's
> * ASM block
> @@ -237,6 +266,11 @@ struct testdef {
> testfunc_t test;
> int facility_bit;
> } testlist[] = {
> + /* PLO was introduced in the very first 64-bit machine generation.
> + * Hence it is assumed PLO is always installed in Z Arch .
^
accidental whitespace

> + */
> + { "PLO", cpu_subfunc.plo, sizeof(cpu_subfunc.plo),
> + test_plo_asm_block, 1 },
> /* MSA - Facility bit 17 */
> { "KMAC", cpu_subfunc.kmac, sizeof(cpu_subfunc.kmac),
> test_kmac_asm_block, 17 },