anv: Support multiple engines with DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT

v2 (Jason Ekstrand):
 - Separate the anv_gem interface from anv_queue internals
 - Rework on top of the new anv_queue_family stuff

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8667>

src/intel/vulkan/anv_gem.c

@@ -374,6 +374,90 @@ anv_gem_create_context(struct anv_device *device)
    return create.ctx_id;
 }
 
+int
+anv_gem_create_context_engines(struct anv_device *device,
+                               const struct drm_i915_query_engine_info *info,
+                               int num_engines, uint16_t *engine_classes)
+{
+   const size_t engine_inst_sz = 2 * sizeof(__u16); /* 1 class, 1 instance */
+   const size_t engines_param_size =
+      sizeof(__u64) /* extensions */ + num_engines * engine_inst_sz;
+
+   void *engines_param = malloc(engines_param_size);
+   assert(engines_param);
+   *(__u64*)engines_param = 0;
+   __u16 *class_inst_ptr = (__u16*)(((__u64*)engines_param) + 1);
+
+   /* For each type of drm_i915_gem_engine_class of interest, we keep track of
+    * the previous engine instance used.
+    */
+   int last_engine_idx[] = {
+      [I915_ENGINE_CLASS_RENDER] = -1,
+   };
+
+   int i915_engine_counts[] = {
+      [I915_ENGINE_CLASS_RENDER] =
+         anv_gem_count_engines(info, I915_ENGINE_CLASS_RENDER),
+   };
+
+   /* For each queue, we look for the next instance that matches the class we
+    * need.
+    */
+   for (int i = 0; i < num_engines; i++) {
+      uint16_t engine_class = engine_classes[i];
+      if (i915_engine_counts[engine_class] <= 0) {
+         free(engines_param);
+         return -1;
+      }
+
+      /* Run through the engines reported by the kernel looking for the next
+       * matching instance. We loop in case we want to create multiple
+       * contexts on an engine instance.
+       */
+      int engine_instance = -1;
+      for (int i = 0; i < info->num_engines; i++) {
+         int *idx = &last_engine_idx[engine_class];
+         if (++(*idx) >= info->num_engines)
+            *idx = 0;
+         if (info->engines[*idx].engine.engine_class == engine_class) {
+            engine_instance = info->engines[*idx].engine.engine_instance;
+            break;
+         }
+      }
+      if (engine_instance < 0) {
+         free(engines_param);
+         return -1;
+      }
+
+      *class_inst_ptr++ = engine_class;
+      *class_inst_ptr++ = engine_instance;
+   }
+
+   assert((uintptr_t)engines_param + engines_param_size ==
+          (uintptr_t)class_inst_ptr);
+
+   struct drm_i915_gem_context_create_ext_setparam set_engines = {
+      .base = {
+         .name = I915_CONTEXT_CREATE_EXT_SETPARAM,
+      },
+      .param = {
+	 .param = I915_CONTEXT_PARAM_ENGINES,
+         .value = (uintptr_t)engines_param,
+         .size = engines_param_size,
+      }
+   };
+   struct drm_i915_gem_context_create_ext create = {
+      .flags = I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS,
+      .extensions = (uintptr_t)&set_engines,
+   };
+   int ret = gen_ioctl(device->fd, DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT, &create);
+   free(engines_param);
+   if (ret == -1)
+      return -1;
+
+   return create.ctx_id;
+}
+
 int
 anv_gem_destroy_context(struct anv_device *device, int context)
 {