[v2,09/23] virtio-gpu api: blob resources

Commit Message

Gurchetan Singh Sept. 2, 2020, 9:08 p.m. UTC

From: Gerd Hoffmann <[e-mail]>

A blob resource is a container for:
   - VIRTGPU_BLOB_MEM_GUEST: a guest memory allocation
     (referred to as a "guest-only blob resource")

   - VIRTGPU_BLOB_MEM_HOST3D: a host3d memory allocation
     (referred to as a "host-only blob resource")

   - VIRTGPU_BLOB_MEM_HOST3D_GUEST: a guest + host3d memory allocation
     (referred to as a "default blob resource").

The memory properties of the blob resource must be described by
`blob_mem`.

For default and guest only blob resources set, `nents` guest system
pages are assigned to the resource.  For default blob resources,
these guest pages are used for transfer operations. Attach/detach is
also possible to allow swap-in/swap-out, but isn't required since it
may not be applicable to future blob mem types
(shared guest/guest vram).

Host allocations depend on whether the 3D is supported. If 3D is not
supported, the only valid field for `blob_mem` is
VIRTGPU_BLOB_MEM_GUEST.

If 3D is supported, the virtio-gpu resource is created from the
context local object identified by the `blob_id`. The actual host
allocation done by the EXECBUFFER ioctl or for convenience the
`cmd` field in the RESOURCE_CREATE_BLOB ioctl.

Userspace must specify if the blob resource is intended to be used
for userspace mapping, sharing between virtio-gpu contexts and/or
sharing between virtio devices. This is done via `blob_flags`.

For 3D hosts, both VIRTIO_GPU_CMD_TRANSFER_TO_HOST_3D and
VIRTIO_GPU_CMD_TRANSFER_FROM_HOST_3D may be used to update
the host resource. There is no restriction on the image/buffer
view the guest/host userspace has on the blob resource.

VIRTIO_GPU_CMD_SET_SCANOUT_BLOB / VIRTIO_GPU_CMD_RESOURCE_FLUSH may
be used with blob resources as well.  The modifier is intentionally
left out of SCANOUT_BLOB, and auxilary blobs are also left out
as a simplification.

The use case for blob resources is zero-copy, needed for coherent
memory in virglrenderer. Host only blob resources are not mappable
without the feature described in the next patch, but are shareable.

Future work:
   - Emulated coherent `blob_mem` type for QEMU/vhost-user
   - A `blob_mem` type for guest-only resources imported in
     cache-coherent FOSS GPU/display drivers.
   - Display integration involving the blob model using seamless
     Wayland windows.

Signed-off-by: Gerd Hoffmann <[e-mail]>
Co-developed-by: Gurchetan Singh <[e-mail]>
Signed-off-by: Gurchetan Singh <[e-mail]>
Acked-by: Tomeu Vizoso <[e-mail]>
Acked-by: Chia-I Wu <[e-mail]>
Acked-by: Lingfeng Yang <[e-mail]>
---
 include/uapi/drm/virtgpu_drm.h  | 37 +++++++++++++++++++++++++++-
 include/uapi/linux/virtio_gpu.h | 43 +++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 1 deletion(-)

Comments

Gerd Hoffmann Sept. 9, 2020, 6:55 a.m. UTC | #1

Hi,

> @@ -100,7 +102,7 @@ struct drm_virtgpu_resource_info {
>  	__u32 bo_handle;
>  	__u32 res_handle;
>  	__u32 size;
> -	__u32 stride;
> +	__u32 blob_mem;
>  };

Huh?  This is not in the virtio spec update proposed.

>  struct drm_virtgpu_3d_box {
> @@ -117,6 +119,8 @@ struct drm_virtgpu_3d_transfer_to_host {
>  	struct drm_virtgpu_3d_box box;
>  	__u32 level;
>  	__u32 offset;
> +	__u32 stride;
> +	__u32 layer_stride;
>  };

Same here.

>  struct drm_virtgpu_3d_transfer_from_host {
> @@ -124,6 +128,8 @@ struct drm_virtgpu_3d_transfer_from_host {
>  	struct drm_virtgpu_3d_box box;
>  	__u32 level;
>  	__u32 offset;
> +	__u32 stride;
> +	__u32 layer_stride;
>  };

And here.

take care,
  Gerd

PS: cherry-picked patches 1-3 into drm-misc-next.

Gurchetan Singh Sept. 17, 2020, 12:16 a.m. UTC | #2

On Tue, Sep 8, 2020 at 11:55 PM Gerd Hoffmann <[e-mail]> wrote:

>   Hi,
>
> > @@ -100,7 +102,7 @@ struct drm_virtgpu_resource_info {
> >       __u32 bo_handle;
> >       __u32 res_handle;
> >       __u32 size;
> > -     __u32 stride;
> > +     __u32 blob_mem;
> >  };
>
> Huh?  This is not in the virtio spec update proposed.
>
> >  struct drm_virtgpu_3d_box {
> > @@ -117,6 +119,8 @@ struct drm_virtgpu_3d_transfer_to_host {
> >       struct drm_virtgpu_3d_box box;
> >       __u32 level;
> >       __u32 offset;
> > +     __u32 stride;
> > +     __u32 layer_stride;
> >  };
>
> Same here.
>
> >  struct drm_virtgpu_3d_transfer_from_host {
> > @@ -124,6 +128,8 @@ struct drm_virtgpu_3d_transfer_from_host {
> >       struct drm_virtgpu_3d_box box;
> >       __u32 level;
> >       __u32 offset;
> > +     __u32 stride;
> > +     __u32 layer_stride;
> >  };


> And here.
>

Separated out the virtio and DRM api changes, as per your recommendation.
The virtio spec changes should match v6 of the proposed spec.  Explanations
for these specific DRM changes here are in patch 16 & patch 17 of the v3
implementation.


> take care,
>   Gerd
>
> PS: cherry-picked patches 1-3 into drm-misc-next.
>
>

Patch

diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index f06a789f34cd9..bb224f604c9e3 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -46,6 +46,7 @@  extern "C" {
 #define DRM_VIRTGPU_TRANSFER_TO_HOST 0x07
 #define DRM_VIRTGPU_WAIT     0x08
 #define DRM_VIRTGPU_GET_CAPS  0x09
+#define DRM_VIRTGPU_RESOURCE_CREATE_BLOB 0x0a
 
 #define VIRTGPU_EXECBUF_FENCE_FD_IN	0x01
 #define VIRTGPU_EXECBUF_FENCE_FD_OUT	0x02
@@ -71,6 +72,7 @@  struct drm_virtgpu_execbuffer {
 
 #define VIRTGPU_PARAM_3D_FEATURES 1 /* do we have 3D features in the hw */
 #define VIRTGPU_PARAM_CAPSET_QUERY_FIX 2 /* do we have the capset fix */
+#define VIRTGPU_PARAM_RESOURCE_BLOB 3 /* DRM_VIRTGPU_RESOURCE_CREATE_BLOB */
 
 struct drm_virtgpu_getparam {
 	__u64 param;
@@ -100,7 +102,7 @@  struct drm_virtgpu_resource_info {
 	__u32 bo_handle;
 	__u32 res_handle;
 	__u32 size;
-	__u32 stride;
+	__u32 blob_mem;
 };
 
 struct drm_virtgpu_3d_box {
@@ -117,6 +119,8 @@  struct drm_virtgpu_3d_transfer_to_host {
 	struct drm_virtgpu_3d_box box;
 	__u32 level;
 	__u32 offset;
+	__u32 stride;
+	__u32 layer_stride;
 };
 
 struct drm_virtgpu_3d_transfer_from_host {
@@ -124,6 +128,8 @@  struct drm_virtgpu_3d_transfer_from_host {
 	struct drm_virtgpu_3d_box box;
 	__u32 level;
 	__u32 offset;
+	__u32 stride;
+	__u32 layer_stride;
 };
 
 #define VIRTGPU_WAIT_NOWAIT 1 /* like it */
@@ -140,6 +146,31 @@  struct drm_virtgpu_get_caps {
 	__u32 pad;
 };
 
+struct drm_virtgpu_resource_create_blob {
+#define VIRTGPU_BLOB_MEM_GUEST             0x0001
+#define VIRTGPU_BLOB_MEM_HOST3D            0x0002
+#define VIRTGPU_BLOB_MEM_HOST3D_GUEST      0x0003
+
+#define VIRTGPU_BLOB_FLAG_USE_MAPPABLE     0x0001
+#define VIRTGPU_BLOB_FLAG_USE_SHAREABLE    0x0002
+#define VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
+	/* zero is invalid blob_mem */
+	__u32 blob_mem;
+	__u32 blob_flags;
+	__u32 bo_handle;
+	__u32 res_handle;
+	__u64 size;
+
+	/*
+	 * for 3D contexts with VIRTGPU_BLOB_MEM_HOST3D_GUEST and
+	 * VIRTGPU_BLOB_MEM_HOST3D otherwise, must be zero.
+	 */
+	__u32 pad;
+	__u32 cmd_size;
+	__u64 cmd;
+	__u64 blob_id;
+};
+
 #define DRM_IOCTL_VIRTGPU_MAP \
 	DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_MAP, struct drm_virtgpu_map)
 
@@ -175,6 +206,10 @@  struct drm_virtgpu_get_caps {
 	DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_GET_CAPS, \
 	struct drm_virtgpu_get_caps)
 
+#define DRM_IOCTL_VIRTGPU_RESOURCE_CREATE_BLOB				\
+	DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_RESOURCE_CREATE_BLOB,	\
+		struct drm_virtgpu_resource_create_blob)
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
index 747a5c5cc4e60..4ddf2fe342ed0 100644
--- a/include/uapi/linux/virtio_gpu.h
+++ b/include/uapi/linux/virtio_gpu.h
@@ -55,6 +55,11 @@ 
  */
 #define VIRTIO_GPU_F_RESOURCE_UUID       2
 
+/*
+ * VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB
+ */
+#define VIRTIO_GPU_F_RESOURCE_BLOB       3
+
 enum virtio_gpu_ctrl_type {
 	VIRTIO_GPU_UNDEFINED = 0,
 
@@ -71,6 +76,8 @@  enum virtio_gpu_ctrl_type {
 	VIRTIO_GPU_CMD_GET_CAPSET,
 	VIRTIO_GPU_CMD_GET_EDID,
 	VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID,
+	VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB,
+	VIRTIO_GPU_CMD_SET_SCANOUT_BLOB,
 
 	/* 3d commands */
 	VIRTIO_GPU_CMD_CTX_CREATE = 0x0200,
@@ -359,4 +366,40 @@  struct virtio_gpu_resp_resource_uuid {
 	__u8 uuid[16];
 };
 
+/* VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB */
+struct virtio_gpu_resource_create_blob {
+	struct virtio_gpu_ctrl_hdr hdr;
+	__le32 resource_id;
+#define VIRTIO_GPU_BLOB_MEM_GUEST             0x0001
+#define VIRTIO_GPU_BLOB_MEM_HOST3D            0x0002
+#define VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST      0x0003
+
+#define VIRTIO_GPU_BLOB_FLAG_USE_MAPPABLE     0x0001
+#define VIRTIO_GPU_BLOB_FLAG_USE_SHAREABLE    0x0002
+#define VIRTIO_GPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
+	/* zero is invalid blob mem */
+	__le32 blob_mem;
+	__le32 blob_flags;
+	__le64 blob_id;
+	__le64 size;
+	__le32 nr_entries;
+	/*
+	 * sizeof(nr_entries * virtio_gpu_mem_entry) bytes follow
+	 */
+};
+
+/* VIRTIO_GPU_CMD_SET_SCANOUT_BLOB */
+struct virtio_gpu_set_scanout_blob {
+	struct virtio_gpu_ctrl_hdr hdr;
+	struct virtio_gpu_rect r;
+	__le32 scanout_id;
+	__le32 resource_id;
+	__le32 width;
+	__le32 height;
+	__le32 format;
+	__le32 padding;
+	__le32 strides[4];
+	__le32 offsets[4];
+};
+
 #endif