On 4/2/25 20:45, Sergio Lopez wrote: > 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. > > There has been a discussion in virtio-comments about whether the > information about alignment restrictions must be shared in a generic or > in a device-specific way, favoring the latter: > > https://lore.kernel.org/virtio-comment/cy8pr12mb7195b5e575099cd9ca1f2f39dc...@cy8pr12mb7195.namprd12.prod.outlook.com/T/#t > > v2: > - Rebase on top of current upstream. > - Make a reference in the cover to the discussion about how device > page alignment restrictions should be shared with the driver. > > Signed-off-by: Sergio Lopez <[email protected]> > --- > 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(-) > --- > base-commit: acc4d5ff0b61eb1715c498b6536c38c1feb7f3c1 > change-id: 20250402-virtio-gpu-host-page-size-282c99dfe44c > > Best regards,
Hi Sergio, Curious if this feature still wanted. The protocol was updated many months ago with the VIRTIO_GPU_F_BLOB_ALIGNMENT addition. -- Best regards, Dmitry
