drm/i915: Reject more ioctls for userptr, v2.

There are a couple of ioctl's related to tiling and cache placement,
that make no sense for userptr, reject those:
- i915_gem_set_tiling_ioctl()
    Tiling should always be linear for userptr. Changing placement will
    fail with -ENXIO.
- i915_gem_set_caching_ioctl()
    Userptr memory should always be cached. Changing caching mode will
    fail with -ENXIO.
- i915_gem_set_domain_ioctl()
    Still temporarily allowed to work as intended, it's used to check
    userptr validity. With the reworked userptr code, it will keep
    working for this usecase.

This plus the previous changes have been tested against beignet
by using its own unit tests, and intel-video-compute by using
piglit's opencl tests.

Changes since v1:
- set_domain was apparently used in iris for checking userptr validity,
  keep it working as intended.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-14-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -11905,7 +11905,7 @@ static int intel_user_framebuffer_create_handle(struct drm_framebuffer *fb,
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 
-	if (obj->userptr.mm) {
+	if (i915_gem_object_is_userptr(obj)) {
 		drm_dbg(&i915->drm,
 			"attempting to use a userptr for a framebuffer, denied\n");
 		return -EINVAL;

drivers/gpu/drm/i915/gem/i915_gem_domain.c

@@ -335,7 +335,14 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
 	 * not allowed to be changed by userspace.
 	 */
 	if (i915_gem_object_is_proxy(obj)) {
-		ret = -ENXIO;
+		/*
+		 * Silently allow cached for userptr; the vulkan driver
+		 * sets all objects to cached
+		 */
+		if (!i915_gem_object_is_userptr(obj) ||
+		    args->caching != I915_CACHING_CACHED)
+			ret = -ENXIO;
+
 		goto out;
 	}
 
@@ -532,7 +539,8 @@ i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 	 * tracking for that backing storage. The proxy object is always
 	 * considered to be outside of any cache domain.
 	 */
-	if (i915_gem_object_is_proxy(obj)) {
+	if (i915_gem_object_is_proxy(obj) &&
+	    !i915_gem_object_is_userptr(obj)) {
 		err = -ENXIO;
 		goto out;
 	}

drivers/gpu/drm/i915/gem/i915_gem_object.h

@@ -548,6 +548,12 @@ void __i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
 void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
 					      enum fb_op_origin origin);
 
+static inline bool
+i915_gem_object_is_userptr(struct drm_i915_gem_object *obj)
+{
+	return obj->userptr.mm;
+}
+
 static inline void
 i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
 				  enum fb_op_origin origin)

drivers/gpu/drm/i915/gem/i915_gem_userptr.c

@@ -721,7 +721,8 @@ static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
 	.name = "i915_gem_object_userptr",
 	.flags = I915_GEM_OBJECT_IS_SHRINKABLE |
 		 I915_GEM_OBJECT_NO_MMAP |
-		 I915_GEM_OBJECT_ASYNC_CANCEL,
+		 I915_GEM_OBJECT_ASYNC_CANCEL |
+		 I915_GEM_OBJECT_IS_PROXY,
 	.get_pages = i915_gem_userptr_get_pages,
 	.put_pages = i915_gem_userptr_put_pages,
 	.dmabuf_export = i915_gem_userptr_dmabuf_export,