UPSTREAM: drm/virtio: implement context init: handle VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK

For the Sommelier guest Wayland proxy, it's desirable for the
DRM fd to be pollable in response to an host compositor event.
This can also be used by the 3D driver to poll events on a CPU
timeline.

This enables the DRM fd associated with a particular 3D context
to be polled independent of KMS events.  The parameter
VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK specifies the pollable
rings.

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Acked-by: Nicholas Verne <nverne@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20210921232024.817-11-gurchetansingh@chromium.org


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 8d6b006e)

BUG=b:176158390, b:203009046, b:230100768
TEST=gfxbench and deqp-cts in arcvm

Signed-off-by: Rob Clark <robdclark@chromium.org>
Change-Id: Ied9aedd1343b990a07f2e07dd85ec3e681a67627
Disallow-Recycled-Builds: test-failures
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3469489


Reviewed-by: Chia-I Wu <olv@google.com>
Reviewed-by: Ryan Neph <ryanneph@google.com>