[PATCH i-g-t v2 3/4] tests/intel/xe_oa: Add a test for tail address wrap

[Umesh Nerlige Ramappa]

Add a test to verify that the HW wraps to start of the OA buffer when a
report does not fit in the remaining space in the buffer.

v2:
- Make test more robust

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
 tests/intel/xe_oa.c | 97 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/tests/intel/xe_oa.c b/tests/intel/xe_oa.c
index d10ef00d6abc..24442e4b83c6 100644
--- a/tests/intel/xe_oa.c
+++ b/tests/intel/xe_oa.c
@@ -4537,6 +4537,95 @@ static void closed_fd_and_unmapped_access(const struct drm_xe_engine_class_insta
 	try_invalid_access(vaddr);
 }
 
+static void read_reports(int fd, uint8_t *buf, size_t size)
+{
+	int len, total = 0;
+
+	while (total < size) {
+		len = read(fd, &buf[total], size - total);
+		if (len == -1 && (errno == EIO || errno == EINTR))
+			continue;
+
+		igt_assert(len);
+		total += len;
+	}
+}
+
+/**
+ * SUBTEST: tail-address-wrap
+ * Description: Test tail address wrap on odd format sizes. Ensure that the
+ * format size is not a power of 2. This means that the last report will not be
+ * broken down across the OA buffer end. Instead it will be written to the
+ * beginning of the OA buffer. We will check the end of the buffer to ensure it
+ * has zeroes in it.
+ */
+static void
+test_tail_address_wrap(const struct drm_xe_engine_class_instance *hwe, size_t oa_buffer_size)
+{
+	struct intel_xe_perf_metric_set *test_set = metric_set(hwe);
+	uint64_t exponent = max_oa_exponent_for_period_lte(20000);
+	uint64_t buffer_size = oa_buffer_size ?: buffer_fill_size;
+	uint64_t fmt = test_set->perf_oa_format;
+	uint64_t properties[] = {
+		DRM_XE_OA_PROPERTY_OA_UNIT_ID, 0,
+		DRM_XE_OA_PROPERTY_SAMPLE_OA, true,
+		DRM_XE_OA_PROPERTY_OA_METRIC_SET, test_set->perf_oa_metrics_set,
+		DRM_XE_OA_PROPERTY_OA_FORMAT, __ff(fmt),
+		DRM_XE_OA_PROPERTY_OA_PERIOD_EXPONENT, exponent,
+		DRM_XE_OA_PROPERTY_OA_ENGINE_INSTANCE, hwe->engine_instance,
+		DRM_XE_OA_PROPERTY_OA_BUFFER_SIZE, buffer_size,
+		DRM_XE_OA_PROPERTY_OA_DISABLED, true,
+	};
+	struct intel_xe_oa_open_prop param = {
+		.num_properties = ARRAY_SIZE(properties) / 2,
+		.properties_ptr = to_user_pointer(properties),
+	};
+	uint32_t fmt_size = get_oa_format(fmt).size;
+	uint32_t fit_reports = buffer_size / fmt_size;
+	uint32_t extra_reports = 10;
+	uint32_t total_reports = fit_reports + extra_reports;
+	uint32_t total_size = total_reports * fmt_size;
+	uint8_t *buf = malloc(total_size);
+
+	uint32_t wrap_offset = (fit_reports * fmt_size) >> 2;
+	uint32_t end_offset = buffer_size >> 2;
+	uint32_t *zero_area, *buffer_end, *buffer_start;
+	int i;
+
+	/* Ensure report does not fit */
+	igt_require(wrap_offset < end_offset);
+
+	stream_fd = __perf_open(drm_fd, &param, false);
+
+	/* Read fit_reports + extra_reports */
+	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_ENABLE, 0);
+	read_reports(stream_fd, buf, total_size);
+	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_DISABLE, 0);
+
+	/* Quick check for valid reports */
+	for (i = 0; i < total_reports; i++) {
+		uint32_t *report = (uint32_t *)&buf[i * fmt_size];
+
+		igt_assert(report_reason(report) && oa_timestamp(report, fmt));
+	}
+
+	/* mmap the buffer and check that the end of the buffer has zeroes */
+	buffer_start = mmap(0, buffer_size, PROT_READ, MAP_PRIVATE, stream_fd, 0);
+	igt_assert(buffer_start);
+
+	zero_area = buffer_start + wrap_offset;
+	buffer_end = buffer_start + end_offset;
+
+	/* Ensure HW did not write to this area */
+	while (zero_area < buffer_end)
+		igt_assert_eq(*zero_area++, 0);
+
+	munmap(buffer_start, buffer_size);
+
+	__perf_close(stream_fd);
+	free(buf);
+}
+
 /**
  * SUBTEST: map-oa-buffer
  * Description: Verify mapping of oa buffer
@@ -5095,6 +5184,14 @@ igt_main
 				closed_fd_and_unmapped_access(hwe);
 	}
 
+	igt_subtest_with_dynamic("tail-address-wrap") {
+		long k = random() % num_buf_sizes;
+
+		igt_require(oau->capabilities & DRM_XE_OA_CAPS_OA_BUFFER_SIZE);
+		__for_one_hwe_in_oag_w_arg(hwe, buf_sizes[k].name)
+			test_tail_address_wrap(hwe, buf_sizes[k].size);
+	}
+
 	igt_subtest_group {
 		igt_fixture {
 			perf_init_whitelist();
-- 
2.43.0