[PATCH 0/2] drm/virtio: introduce the HOST_PAGE_SIZE feature

[Sergio Lopez <slp@redhat.com>]

There's an incresing number of machines supporting multiple page sizes
and on these machines the host and a guest can be running, each one,
with a different page size.

For what pertains to virtio-gpu, this is not a problem if the page size
of the guest happens to be bigger or equal than the host, but will
potentially lead to failures in memory allocations and/or mappings
otherwise.

To improve this situation, we introduce here the HOST_PAGE_SIZE feature.
This feature indicates that the host has an extended virtio_gpu_config
structure that include it's own page size a new field.

On the second commit, we also add a new param that can be read with
VIRTGPU_GETPARAM by userspace applications running in the guest to
obtain the host's page size and find out the right alignment to be used
in shared memory allocations.

Sergio Lopez (2):
  drm/virtio: introduce the HOST_PAGE_SIZE feature
  drm/virtio: add VIRTGPU_PARAM_HOST_PAGE_SIZE to params

 drivers/gpu/drm/virtio/virtgpu_drv.c   |  1 +
 drivers/gpu/drm/virtio/virtgpu_drv.h   |  2 ++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c |  5 +++++
 drivers/gpu/drm/virtio/virtgpu_kms.c   | 13 ++++++++++---
 include/uapi/drm/virtgpu_drm.h         |  1 +
 include/uapi/linux/virtio_gpu.h        |  5 +++++
 6 files changed, 24 insertions(+), 3 deletions(-)

-- 
2.45.2