nouveau/ws: add API to query if the context was killed

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24326>

src/nouveau/winsys/nouveau_context.c

@@ -192,3 +192,19 @@ nouveau_ws_context_destroy(struct nouveau_ws_context *context)
    nouveau_ws_channel_dealloc(context->dev->fd, context->channel);
    FREE(context);
 }
+
+bool
+nouveau_ws_context_killed(struct nouveau_ws_context *context)
+{
+   /* we are using the normal pushbuf submission ioctl as this is how nouveau implemented this on
+    * the kernel side.
+    * And as long as we submit nothing (e.g. nr_push is 0) it's more or less a noop on the kernel
+    * side.
+    */
+   struct drm_nouveau_gem_pushbuf req = {
+      .channel = context->channel,
+   };
+   int ret = drmCommandWriteRead(context->dev->fd, DRM_NOUVEAU_GEM_PUSHBUF, &req, sizeof(req));
+   /* nouveau returns ENODEV once the channel was killed */
+   return ret == -ENODEV;
+}

src/nouveau/winsys/nouveau_context.h

@@ -22,6 +22,7 @@ struct nouveau_ws_context {
 };
 
 int nouveau_ws_context_create(struct nouveau_ws_device *, struct nouveau_ws_context **out);
+bool nouveau_ws_context_killed(struct nouveau_ws_context *);
 void nouveau_ws_context_destroy(struct nouveau_ws_context *);
 
 #endif