ring_idx zero is the CPU ring, others map to the priority level, as each
priority level for a given drm_file on the host kernel side maps to a
single fence timeline.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16086>
Add a new backend to enable using native driver in a VM guest, via a new
virtgpu context type which (indirectly) makes host kernel interface
available in guest and handles the details of mapping buffers to guest,
etc.
Note that fence-fd's are currently a bit awkward, in that they get
signaled by the guest kernel driver (drm/virtio) once virglrenderer in
the host has processed the execbuf, not when host kernel has signaled
the submit fence. For passing buffers to the host (virtio-wl) the egl
context in virglrenderer is used to create a fence on the host side.
But use of out-fence-fd's in guest could have slightly unexpected
results. For this reason we limit all submitqueues to default priority
(so they cannot be preepmted by host egl context). AFAICT virgl and
venus have a similar problem, which will eventually be solveable once we
have RESOURCE_CREATE_SYNC.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14900>
This change allows creating contexts of depending on set of
context parameters. The meaning of each of the parameters
is listed below:
1) VIRTGPU_CONTEXT_PARAM_CAPSET_ID
This determines the type of a context based on the capability set
ID. For example, the current capsets:
VIRTIO_GPU_CAPSET_VIRGL
VIRTIO_GPU_CAPSET_VIRGL2
define a Gallium, TGSI based "virgl" context. We only need 1 capset
ID per context type, though virgl has two due a bug that has since
been fixed.
The use case is the "gfxstream" rendering library and "venus"
renderer.
gfxstream doesn't do Gallium/TGSI translation and mostly relies on
auto-generated API streaming. Certain users prefer gfxstream over
virgl for GLES on GLES emulation. {gfxstream vk}/{venus} are also
required for Vulkan emulation.
The goal is for guest userspace to choose the optimal context type
depending on the situation/hardware.
2) VIRTGPU_CONTEXT_PARAM_NUM_RINGS
This tells the number of independent command rings that the context
will use. This value may be zero and is inferred to be zero if
VIRTGPU_CONTEXT_PARAM_NUM_RINGS is not passed in. This is backwards
compatibility for virgl, which has one big giant command ring for all
commands.
The maxiumum number of rings is 32. In practice, multi-queue or
multi-ring submission is used for powerful dGPUs and virtio-gpu
may not be the best option in that case (see PCI passthrough or
rendernode forwarding).
3) VIRTGPU_CONTEXT_PARAM_POLL_RING_IDX_MASK
This is a mask of ring indices for which the DRM fd is pollable.
For example, if VIRTGPU_CONTEXT_PARAM_NUM_RINGS is 2, then the mask
may be:
[ring idx] | [1 << ring_idx] | final mask
-------------------------------------------
0 1 1
1 2 3
The "Sommelier" guest Wayland proxy uses this to poll for events
from the host compositor.
Reviewed-by: Anthoine Bourgeois <anthoine.bourgeois@gmail.com>
Tested-by: Anthoine Bourgeois <anthoine.bourgeois@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7712>
Rob Clark
Gurchetan Singh