drm/i915/uapi: introduce drm_i915_gem_create_ext

Same old gem_create but with now with extensions support. This is needed
to support various upcoming usecases.

v2:(Chris)
- Use separate ioctl number for gem_create_ext, instead of hijacking
the existing gem_create ioctl, otherwise we run into the issue
with being unable to detect if the kernel supports the new extension
behaviour.
- We now have gem_create_ext.flags, which should be zeroed.
- I915_GEM_CREATE_EXT_SETPARAM value is now zero, since this is the
index into our array of extensions.
- Setup a "vanilla" object which we can directly apply our extensions
to.
v3:(Daniel & Jason)
- drop I915_GEM_CREATE_EXT_SETPARAM. Instead just have each extension
do one thing only, instead of generic setparam which can cover
various use cases.
- add some kernel-doc.

Signed-off-by: Matthew Auld <[e-mail]>
Signed-off-by: CQ Tang <[e-mail]>
Cc: Joonas Lahtinen <[e-mail]>
Cc: Daniele Ceraolo Spurio <[e-mail]>
Cc: Lionel Landwerlin <[e-mail]>
Cc: Jordan Justen <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Kenneth Graunke <[e-mail]>
Cc: Jason Ekstrand <[e-mail]>
Cc: Dave Airlie <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Reviewed-by: Kenneth Graunke <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/gem/i915_gem_create.c

···
 
 #include "i915_drv.h"
 #include "i915_trace.h"
+#include "i915_user_extensions.h"
 
 static int i915_gem_publish(struct drm_i915_gem_object *obj,
 			    struct drm_file *file,
···
 	obj = i915_gem_object_alloc();
 	if (!obj)
 		return -ENOMEM;
+
+	ret = i915_gem_setup(obj,
+			     intel_memory_region_by_type(i915,
+							 INTEL_MEMORY_SYSTEM),
+			     args->size);
+	if (ret)
+		goto object_free;
+
+	return i915_gem_publish(obj, file, &args->size, &args->handle);
+
+object_free:
+	i915_gem_object_free(obj);
+	return ret;
+}
+
+struct create_ext {
+	struct drm_i915_private *i915;
+	struct drm_i915_gem_object *vanilla_object;
+};
+
+static const i915_user_extension_fn create_extensions[] = {
+};
+
+/**
+ * Creates a new mm object and returns a handle to it.
+ * @dev: drm device pointer
+ * @data: ioctl data blob
+ * @file: drm file pointer
+ */
+int
+i915_gem_create_ext_ioctl(struct drm_device *dev, void *data,
+			  struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct drm_i915_gem_create_ext *args = data;
+	struct create_ext ext_data = { .i915 = i915 };
+	struct drm_i915_gem_object *obj;
+	int ret;
+
+	if (args->flags)
+		return -EINVAL;
+
+	i915_gem_flush_free_objects(i915);
+
+	obj = i915_gem_object_alloc();
+	if (!obj)
+		return -ENOMEM;
+
+	ext_data.vanilla_object = obj;
+	ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
+				   create_extensions,
+				   ARRAY_SIZE(create_extensions),
+				   &ext_data);
+	if (ret)
+		goto object_free;
 
 	ret = i915_gem_setup(obj,
 			     intel_memory_region_by_type(i915,

drivers/gpu/drm/i915/gem/i915_gem_ioctls.h

···
 			struct drm_file *file);
 int i915_gem_create_ioctl(struct drm_device *dev, void *data,
 			  struct drm_file *file);
+int i915_gem_create_ext_ioctl(struct drm_device *dev, void *data,
+			      struct drm_file *file);
 int i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
 			       struct drm_file *file);
 int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,

drivers/gpu/drm/i915/i915_drv.c

···
 	DRM_IOCTL_DEF_DRV(I915_GEM_ENTERVT, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 	DRM_IOCTL_DEF_DRV(I915_GEM_LEAVEVT, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CREATE, i915_gem_create_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_GEM_CREATE_EXT, i915_gem_create_ext_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_PREAD, i915_gem_pread_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_PWRITE, i915_gem_pwrite_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_MMAP, i915_gem_mmap_ioctl, DRM_RENDER_ALLOW),

include/uapi/drm/i915_drm.h

···
 #define DRM_I915_QUERY			0x39
 #define DRM_I915_GEM_VM_CREATE		0x3a
 #define DRM_I915_GEM_VM_DESTROY		0x3b
+#define DRM_I915_GEM_CREATE_EXT		0x3c
 /* Must be kept compact -- no holes */
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
···
 #define DRM_IOCTL_I915_GEM_ENTERVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_ENTERVT)
 #define DRM_IOCTL_I915_GEM_LEAVEVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_LEAVEVT)
 #define DRM_IOCTL_I915_GEM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_CREATE, struct drm_i915_gem_create)
+#define DRM_IOCTL_I915_GEM_CREATE_EXT	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_CREATE_EXT, struct drm_i915_gem_create_ext)
 #define DRM_IOCTL_I915_GEM_PREAD	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PREAD, struct drm_i915_gem_pread)
 #define DRM_IOCTL_I915_GEM_PWRITE	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PWRITE, struct drm_i915_gem_pwrite)
 #define DRM_IOCTL_I915_GEM_MMAP		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP, struct drm_i915_gem_mmap)
···
 
 	/** @regions: Info about each supported region */
 	struct drm_i915_memory_region_info regions[];
+};
+
+/**
+ * struct drm_i915_gem_create_ext - Existing gem_create behaviour, with added
+ * extension support using struct i915_user_extension.
+ *
+ * Note that in the future we want to have our buffer flags here, at least for
+ * the stuff that is immutable. Previously we would have two ioctls, one to
+ * create the object with gem_create, and another to apply various parameters,
+ * however this creates some ambiguity for the params which are considered
+ * immutable. Also in general we're phasing out the various SET/GET ioctls.
+ */
+struct drm_i915_gem_create_ext {
+	/**
+	 * @size: Requested size for the object.
+	 *
+	 * The (page-aligned) allocated size for the object will be returned.
+	 *
+	 */
+	__u64 size;
+	/**
+	 * @handle: Returned handle for the object.
+	 *
+	 * Object handles are nonzero.
+	 */
+	__u32 handle;
+	/** @flags: MBZ */
+	__u32 flags;
+	/**
+	 * @extensions: The chain of extensions to apply to this object.
+	 *
+	 * This will be useful in the future when we need to support several
+	 * different extensions, and we need to apply more than one when
+	 * creating the object. See struct i915_user_extension.
+	 *
+	 * If we don't supply any extensions then we get the same old gem_create
+	 * behaviour.
+	 *
+	 */
+	__u64 extensions;
 };
 
 #if defined(__cplusplus)