Re: [PATCH v3 5/5] KVM: s390: selftests: Add regression tests for PLO subfunctions

["Christoph Schlameuss" <schlameuss@linux.ibm.com>]

On Fri Aug 23, 2024 at 3:05 PM 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

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

> ---
>  .../kvm/s390x/cpumodel_subfuncs_test.c        | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c b/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> index fe45fb131583..222ba1cc3cac 100644
> --- a/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> +++ b/tools/testing/selftests/kvm/s390x/cpumodel_subfuncs_test.c
> @@ -19,6 +19,8 @@
>  
>  #include "kvm_util.h"
>  
> +#define PLO_FUNCTION_MAX 256
> +
>  /* Query available CPU subfunctions */
>  struct kvm_s390_vm_cpu_subfunc cpu_subfunc;
>  
> @@ -33,6 +35,31 @@ 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 = 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 < PLO_FUNCTION_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 */
>  static void test_kmac_asm_block(u8 (*query)[16])
>  {
> @@ -196,6 +223,11 @@ 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.
> +	 */
> +	{ "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 },
>  	{ "KMC", cpu_subfunc.kmc, sizeof(cpu_subfunc.kmc), test_kmc_asm_block, 17 },