[kvm-unit-tests PATCH] s390x: Add specification exception test

* [kvm-unit-tests PATCH] s390x: Add specification exception test
@ 2021-07-06 11:54 Janis Schoetterl-Glausch
  2021-07-09  9:22 ` Cornelia Huck
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Janis Schoetterl-Glausch @ 2021-07-06 11:54 UTC (permalink / raw)
  To: Thomas Huth, David Hildenbrand, Janosch Frank
  Cc: Janis Schoetterl-Glausch, Cornelia Huck, Claudio Imbrenda, kvm,
	linux-s390

Generate specification exceptions and check that they occur.
Also generate specification exceptions during a transaction,
which results in another interruption code.
With the iterations argument one can check if specification
exception interpretation occurs, e.g. by using a high value and
checking that the debugfs counters are substantially lower.
The argument is also useful for estimating the performance benefit
of interpretation.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 s390x/Makefile           |   1 +
 lib/s390x/asm/arch_def.h |   1 +
 s390x/spec_ex.c          | 344 +++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg      |   3 +
 4 files changed, 349 insertions(+)
 create mode 100644 s390x/spec_ex.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 8820e99..be100d3 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -23,6 +23,7 @@ tests += $(TEST_DIR)/sie.elf
 tests += $(TEST_DIR)/mvpg.elf
 tests += $(TEST_DIR)/uv-host.elf
 tests += $(TEST_DIR)/edat.elf
+tests += $(TEST_DIR)/spec_ex.elf
 
 tests_binary = $(patsubst %.elf,%.bin,$(tests))
 ifneq ($(HOST_KEY_DOCUMENT),)
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 15cf7d4..7cb0b92 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -229,6 +229,7 @@ static inline uint64_t stctg(int cr)
 	return value;
 }
 
+#define CTL0_TRANSACT_EX_CTL	(63 -  8)
 #define CTL0_LOW_ADDR_PROT	(63 - 35)
 #define CTL0_EDAT		(63 - 40)
 #define CTL0_IEP		(63 - 43)
diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
new file mode 100644
index 0000000..2e05bfb
--- /dev/null
+++ b/s390x/spec_ex.c
@@ -0,0 +1,344 @@
+#include <stdlib.h>
+#include <htmintrin.h>
+#include <libcflat.h>
+#include <asm/barrier.h>
+#include <asm/interrupt.h>
+#include <asm/facility.h>
+
+struct lowcore *lc = (struct lowcore *) 0;
+
+static bool expect_early;
+static struct psw expected_early_pgm_psw;
+static struct psw fixup_early_pgm_psw;
+
+static void fixup_early_pgm_ex(void)
+{
+	if (expect_early) {
+		report(expected_early_pgm_psw.mask == lc->pgm_old_psw.mask
+		       && expected_early_pgm_psw.addr == lc->pgm_old_psw.addr,
+		       "Early program new PSW as expected");
+		expect_early = false;
+	}
+	lc->pgm_old_psw = fixup_early_pgm_psw;
+}
+
+static void lpsw(uint64_t psw)
+{
+	uint32_t *high, *low;
+	uint64_t r0 = 0, r1 = 0;
+
+	high = (uint32_t *) &fixup_early_pgm_psw.mask;
+	low = high + 1;
+
+	asm volatile (
+		"	epsw	%0,%1\n"
+		"	st	%0,%[high]\n"
+		"	st	%1,%[low]\n"
+		"	larl	%0,nop%=\n"
+		"	stg	%0,%[addr]\n"
+		"	lpsw	%[psw]\n"
+		"nop%=:	nop\n"
+		: "+&r"(r0), "+&a"(r1), [high] "=&R"(*high), [low] "=&R"(*low)
+		, [addr] "=&R"(fixup_early_pgm_psw.addr)
+		: [psw] "Q"(psw)
+		: "cc", "memory"
+	);
+}
+
+static void psw_bit_31_32_are_1_0(void)
+{
+	uint64_t bad_psw = 0x000800015eadbeef;
+
+	//bit 12 gets inverted when extending to 128-bit PSW
+	expected_early_pgm_psw.mask = 0x0000000100000000;
+	expected_early_pgm_psw.addr = 0x000000005eadbeef;
+	expect_early = true;
+	lpsw(bad_psw);
+}
+
+static void bad_alignment(void)
+{
+	uint32_t words[5] = {0, 0, 0};
+	uint32_t (*bad_aligned)[4];
+
+	register uint64_t r1 asm("6");
+	register uint64_t r2 asm("7");
+	if (((uintptr_t)&words[0]) & 0xf) {
+		bad_aligned = (uint32_t (*)[4])&words[0];
+	} else {
+		bad_aligned = (uint32_t (*)[4])&words[1];
+	}
+	asm volatile ("lpq %0,%2"
+		      : "=r"(r1), "=r"(r2)
+		      : "T"(*bad_aligned)
+	);
+}
+
+static void not_even(void)
+{
+	uint64_t quad[2];
+
+	register uint64_t r1 asm("7");
+	register uint64_t r2 asm("8");
+	asm volatile (".insn	rxy,0xe3000000008f,%0,%2" //lpq %0,%2
+		      : "=r"(r1), "=r"(r2)
+		      : "T"(quad)
+	);
+}
+
+struct spec_ex_trigger {
+	const char *name;
+	void (*func)(void);
+	bool transactable;
+	void (*fixup)(void);
+};
+
+static const struct spec_ex_trigger spec_ex_triggers[] = {
+	{ "psw_bit_31_32_are_1_0", &psw_bit_31_32_are_1_0, false, &fixup_early_pgm_ex},
+	{ "bad_alignment", &bad_alignment, true, NULL},
+	{ "not_even", &not_even, true, NULL},
+	{ NULL, NULL, true, NULL},
+};
+
+struct args {
+	uint64_t iterations;
+	uint64_t max_retries;
+	uint64_t suppress_info;
+	uint64_t max_failures;
+	bool diagnose;
+};
+
+static void test_spec_ex(struct args *args,
+			 const struct spec_ex_trigger *trigger)
+{
+	uint16_t expected_pgm = PGM_INT_CODE_SPECIFICATION;
+	uint16_t pgm;
+	unsigned int i;
+
+	register_pgm_cleanup_func(trigger->fixup);
+	for (i = 0; i < args->iterations; i++) {
+		expect_pgm_int();
+		trigger->func();
+		pgm = clear_pgm_int();
+		if (pgm != expected_pgm) {
+			report(0,
+			"Program interrupt: expected(%d) == received(%d)",
+			expected_pgm,
+			pgm);
+			return;
+		}
+	}
+	report(1,
+	"Program interrupt: always expected(%d) == received(%d)",
+	expected_pgm,
+	expected_pgm);
+}
+
+#define TRANSACTION_COMPLETED 4
+#define TRANSACTION_MAX_RETRIES 5
+
+static int __attribute__((nonnull))
+with_transaction(void (*trigger)(void), struct __htm_tdb *diagnose)
+{
+	int cc;
+
+	cc = __builtin_tbegin(diagnose);
+	if (cc == _HTM_TBEGIN_STARTED) {
+		trigger();
+		__builtin_tend();
+		return -TRANSACTION_COMPLETED;
+	} else {
+		return -cc;
+	}
+}
+
+static int retry_transaction(const struct spec_ex_trigger *trigger, unsigned int max_retries,
+			     struct __htm_tdb *tdb, uint16_t expected_pgm)
+{
+	int trans_result, i;
+	uint16_t pgm;
+
+	for (i = 0; i < max_retries; i++) {
+		expect_pgm_int();
+		trans_result = with_transaction(trigger->func, tdb);
+		if (trans_result == -_HTM_TBEGIN_TRANSIENT) {
+			mb();
+			pgm = lc->pgm_int_code;
+			if (pgm == 0) {
+				continue;
+			} else if (pgm == expected_pgm) {
+				return 0;
+			}
+		}
+		return trans_result;
+	}
+	return -TRANSACTION_MAX_RETRIES;
+}
+
+#define report_info_if(cond, fmt, ...)			\
+	do {						\
+		if (cond) {				\
+			report_info(fmt, ##__VA_ARGS__);\
+		}					\
+	} while (0)
+
+static void test_spec_ex_trans(struct args *args, const struct spec_ex_trigger *trigger)
+{
+	const uint16_t expected_pgm = PGM_INT_CODE_SPECIFICATION
+			      | PGM_INT_CODE_TX_ABORTED_EVENT;
+	union {
+		struct __htm_tdb tdb;
+		uint64_t dwords[sizeof(struct __htm_tdb) / sizeof(uint64_t)];
+	} diag;
+	unsigned int i, failures = 0;
+	int trans_result;
+
+	if (!test_facility(73)) {
+		report_skip("transactional-execution facility not installed");
+		return;
+	}
+	ctl_set_bit(0, CTL0_TRANSACT_EX_CTL); /* enable transactional-exec */
+
+	register_pgm_cleanup_func(trigger->fixup);
+	for (i = 0; i < args->iterations && failures <= args->max_failures; i++) {
+		trans_result = retry_transaction(trigger, args->max_retries, &diag.tdb, expected_pgm);
+		switch (trans_result) {
+		case 0:
+			continue;
+		case -_HTM_TBEGIN_INDETERMINATE:
+		case -_HTM_TBEGIN_PERSISTENT:
+			report_info_if(failures < args->suppress_info,
+				       "transaction failed with cc %d",
+				       -trans_result);
+			break;
+		case -_HTM_TBEGIN_TRANSIENT:
+			report(0,
+			       "Program interrupt: expected(%d) == received(%d)",
+			       expected_pgm,
+			       clear_pgm_int());
+			goto out;
+		case -TRANSACTION_COMPLETED:
+			report(0,
+			       "Transaction completed without exception");
+			goto out;
+		case -TRANSACTION_MAX_RETRIES:
+			report_info_if(failures < args->suppress_info,
+				       "Retried transaction %u times without exception",
+				       10);
+			break;
+		default:
+			report(0, "Invalid return transaction result");
+			goto out;
+		}
+
+		report_info_if(failures < args->suppress_info,
+			       "transaction abort code: %llu", diag.tdb.abort_code);
+		if (args->diagnose && failures < args->suppress_info) {
+			for (i = 0; i < 32; i++) {
+				report_info("diag+%03d: %016lx", i*8, diag.dwords[i]);
+			}
+		}
+		++failures;
+	}
+	if (failures <= args->max_failures) {
+		report(1,
+		       "Program interrupt: always expected(%d) == received(%d), transaction failures: %u",
+		       expected_pgm,
+		       expected_pgm,
+		       failures);
+	} else {
+		report(0,
+		       "Too many transaction failures: %u", failures);
+	}
+	report_info_if(failures > args->suppress_info,
+		       "Suppressed some transaction failure information messages");
+
+out:
+	ctl_clear_bit(0, CTL0_TRANSACT_EX_CTL);
+}
+
+static struct args parse_args(int argc, char **argv)
+{
+	struct args args = {
+		.iterations = 1,
+		.max_retries = 20,
+		.suppress_info = 20,
+		.diagnose = false
+	};
+	unsigned int i;
+	long parsed;
+	bool error, max_failures = false;
+	char *end;
+
+	for (i = 1; i < argc; i++) {
+		error = true;
+		if (i < argc - 1) {
+			error = *argv[i+1] == '\0';
+			parsed = strtol(argv[i+1], &end, 10);
+			error |= *end != '\0';
+			error |= parsed < 0;
+		}
+
+		if (!strcmp("--iterations", argv[i])) {
+			if (error)
+				report_abort("--iterations needs a positive parameter");
+			args.iterations = parsed;
+			++i;
+		} else if (!strcmp("--max-retries", argv[i])) {
+			if (error)
+				report_abort("--max-retries needs a positive parameter");
+			args.max_retries = parsed;
+			++i;
+		} else if (!strcmp("--suppress-info", argv[i])) {
+			if (error)
+				report_abort("--suppress-info needs a positive parameter");
+			args.suppress_info = parsed;
+			++i;
+		} else if (!strcmp("--max-failures", argv[i])) {
+			if (error)
+				report_abort("--max-failures needs a positive parameter");
+			args.max_failures = parsed;
+			max_failures = true;
+			++i;
+		} else if (!strcmp("--diagnose", argv[i])) {
+			args.diagnose = true;
+		} else if (!strcmp("--no-diagnose", argv[i])) {
+			args.diagnose = false;
+		} else {
+			report_abort("Unsupported parameter '%s'",
+				     argv[i]);
+		}
+	}
+
+	if (!max_failures)
+		args.max_failures = args.iterations / 1000;
+
+	return args;
+}
+
+int main(int argc, char **argv)
+{
+	unsigned int i;
+
+	struct args args = parse_args(argc, argv);
+
+	report_prefix_push("specification exception");
+	for (i = 0; spec_ex_triggers[i].name; i++) {
+		report_prefix_push(spec_ex_triggers[i].name);
+		test_spec_ex(&args, &spec_ex_triggers[i]);
+		report_prefix_pop();
+	}
+	report_prefix_pop();
+
+	report_prefix_push("specification exception during transaction");
+	for (i = 0; spec_ex_triggers[i].name; i++) {
+		if (spec_ex_triggers[i].transactable) {
+			report_prefix_push(spec_ex_triggers[i].name);
+			test_spec_ex_trans(&args, &spec_ex_triggers[i]);
+			report_prefix_pop();
+		}
+	}
+	report_prefix_pop();
+
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index a0ec886..b93aead 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -106,3 +106,6 @@ timeout = 10
 
 [edat]
 file = edat.elf
+
+[spec_ex]
+file = spec_ex.elf

base-commit: bc6f264386b4cb2cadc8b2492315f3e6e8a801a2
-- 
2.31.1


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