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

From: Hariharan Mari
Date: Fri Aug 23 2024 - 09:12:15 EST


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@xxxxxxxxxxxxx>
Signed-off-by: Hariharan Mari <hari55@xxxxxxxxxxxxx>
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
.../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 },
--
2.45.2