docs/interop/vhost-user-gpu.rst

2 Vhost-user-gpu Protocol
7            version 2 or later. See the COPYING file in the top-level
15 The vhost-user-gpu protocol is aiming at sharing the rendering result
16 of a virtio-gpu, done from a vhost-user back-end process to a vhost-user
17 front-end process (such as QEMU). It bears a resemblance to a display
19 back-end as the client, but in a very limited way. Typically, it will
29 Requests are sent by the *back-end*, and the optional replies by the
30 *front-end*.
38 A vhost-user-gpu message (request and reply) consists of 3 header
41 +---------+-------+------+---------+
43 +---------+-------+------+---------+
46 ------
50 :flags: ``u32``, 32-bit bit field:
52  - Bit 2 is the reply flag - needs to be set on each reply
57 -------------
64 +------------+---+---+
65 | scanout-id | x | y |
66 +------------+---+---+
68 :scanout-id: ``u32``, the scanout where the cursor is located
75 +-----+-------+-------+--------+
77 +-----+-------+-------+--------+
88 +------------+---+---+
89 | scanout-id | w | h |
90 +------------+---+---+
92 :scanout-id: ``u32``, the scanout configuration to set
99 +------------+---+---+---+---+------+
100 | scanout-id | x | y | w | h | data |
101 +------------+---+---+---+---+------+
103 :scanout-id: ``u32``, the scanout content to update
112 +------------+---+---+---+---+-----+-----+--------+-------+--------+
113 | scanout-id | x | y | w | h | fdw | fwh | stride | flags | fourcc |
114 +------------+---+---+---+---+-----+-----+--------+-------+--------+
116 :scanout-id: ``u32``, the scanout configuration to set
130 +------------+
131 | scanout-id |
132 +------------+
134 :scanout-id: ``u32``, the scanout to get edid from
140 +----------------+----------+
142 +----------------+----------+
151 -----------
153 In QEMU the vhost-user-gpu message is implemented with the following struct:
175 -----------------
190 -------------
218   Set/show the cursor position.
225   Set/hide the cursor.
239   Set the scanout resolution. To disable a scanout, the dimensions
240   width/height are set to 0.
247   Update the scanout content. The data payload contains the graphical bits.
255   Set the scanout resolution/configuration, and share a DMABUF file
256   descriptor for the scanout content, which is passed as ancillary
257   data. To disable a scanout, the dimensions width/height are set
269   to DMABUF, that must have been set previously with