intel/perf: Implement Xe KMD perf stream read

Xe KMD perf stream reads just returns the samples, there is no header.
For error checking there is other uAPI that is not handled here yet.

So to mantain compatibility here reading the perf stream, adding a
header then copying the sample.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29312>

src/intel/perf/intel_perf.c

@@ -1570,6 +1570,8 @@ intel_perf_stream_read_samples(struct intel_perf_config *perf_config,
    switch (perf_config->devinfo->kmd_type) {
    case INTEL_KMD_TYPE_I915:
       return i915_perf_stream_read_samples(perf_stream_fd, buffer, buffer_len);
+   case INTEL_KMD_TYPE_XE:
+      return xe_perf_stream_read_samples(perf_stream_fd, buffer, buffer_len);
    default:
          unreachable("missing");
          return -1;

src/intel/perf/intel_perf.h

@@ -429,6 +429,8 @@ enum intel_perf_record_type {
    INTEL_PERF_RECORD_TYPE_SAMPLE = 1,
    INTEL_PERF_RECORD_TYPE_OA_REPORT_LOST = 2,
    INTEL_PERF_RECORD_TYPE_OA_BUFFER_LOST = 3,
+   INTEL_PERF_RECORD_TYPE_COUNTER_OVERFLOW = 4,
+   INTEL_PERF_RECORD_TYPE_MMIO_TRG_Q_FULL = 5,
    INTEL_PERF_RECORD_TYPE_MAX,
 };
 

src/intel/perf/xe/intel_perf.c

@@ -178,3 +178,81 @@ xe_perf_stream_set_metrics_id(int perf_stream_fd, uint64_t metrics_set_id)
    return intel_ioctl(perf_stream_fd, DRM_XE_PERF_IOCTL_CONFIG,
                       (void *)(uintptr_t)&prop);
 }
+
+static int
+xe_perf_stream_read_error(int perf_stream_fd, uint8_t *buffer, size_t buffer_len)
+{
+   struct drm_xe_oa_stream_status status = {};
+   struct intel_perf_record_header *header;
+   int ret;
+
+   ret = intel_ioctl(perf_stream_fd, DRM_XE_PERF_IOCTL_STATUS, &status);
+   if (ret)
+      return -errno;
+
+   header = (struct intel_perf_record_header *)buffer;
+   header->pad = 0;
+   header->type = 0;
+   header->size = sizeof(*header);
+   ret = header->size;
+
+   if (status.oa_status & INTEL_PERF_RECORD_TYPE_OA_BUFFER_LOST)
+      header->type = INTEL_PERF_RECORD_TYPE_OA_BUFFER_LOST;
+   else if (status.oa_status & DRM_XE_OASTATUS_REPORT_LOST)
+      header->type = INTEL_PERF_RECORD_TYPE_OA_REPORT_LOST;
+   else if (status.oa_status & DRM_XE_OASTATUS_COUNTER_OVERFLOW)
+      header->type = INTEL_PERF_RECORD_TYPE_COUNTER_OVERFLOW;
+   else if (status.oa_status & DRM_XE_OASTATUS_MMIO_TRG_Q_FULL)
+      header->type = INTEL_PERF_RECORD_TYPE_MMIO_TRG_Q_FULL;
+   else
+      unreachable("missing");
+
+   return header->type ? header->size : -1;
+}
+
+int
+xe_perf_stream_read_samples(int perf_stream_fd, uint8_t *buffer,
+                            size_t buffer_len)
+{
+   uint32_t num_samples = buffer_len / INTEL_PERF_OA_HEADER_SAMPLE_SIZE;
+   const size_t max_bytes_read = num_samples * INTEL_PERF_OA_SAMPLE_SIZE;
+   uint8_t *offset, *offset_samples;
+   int len, i;
+
+   if (buffer_len < INTEL_PERF_OA_HEADER_SAMPLE_SIZE)
+      return -ENOSPC;
+
+   do {
+      len = read(perf_stream_fd, buffer, max_bytes_read);
+   } while (len < 0 && errno == EINTR);
+
+   if (len <= 0) {
+      if (errno == EIO)
+         return xe_perf_stream_read_error(perf_stream_fd, buffer, buffer_len);
+
+      return len < 0 ? -errno : 0;
+   }
+
+   num_samples = len / INTEL_PERF_OA_SAMPLE_SIZE;
+   offset = buffer;
+   offset_samples = buffer + (buffer_len - len);
+   /* move all samples to the end of buffer */
+   memmove(offset_samples, buffer, len);
+
+   /* setup header, then copy sample from the end of buffer */
+   for (i = 0; i < num_samples; i++) {
+      struct intel_perf_record_header *header = (struct intel_perf_record_header *)offset;
+
+      /* TODO: also append REPORT_LOST and BUFFER_LOST */
+      header->type = INTEL_PERF_RECORD_TYPE_SAMPLE;
+      header->pad = 0;
+      header->size = INTEL_PERF_OA_HEADER_SAMPLE_SIZE;
+      offset += sizeof(*header);
+
+      memmove(offset, offset_samples, INTEL_PERF_OA_SAMPLE_SIZE);
+      offset += INTEL_PERF_OA_SAMPLE_SIZE;
+      offset_samples += INTEL_PERF_OA_SAMPLE_SIZE;
+   }
+
+   return offset - buffer;
+}

src/intel/perf/xe/intel_perf.h

@@ -6,6 +6,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
 struct intel_perf_config;
@@ -24,3 +25,5 @@ int xe_perf_stream_open(struct intel_perf_config *perf_config, int drm_fd,
                         bool hold_preemption, bool enable);
 int xe_perf_stream_set_state(int perf_stream_fd, bool enable);
 int xe_perf_stream_set_metrics_id(int perf_stream_fd, uint64_t metrics_set_id);
+int xe_perf_stream_read_samples(int perf_stream_fd, uint8_t *buffer,
+                                size_t buffer_len);