Re: [PATCH v3] virtio-gpu: support blob alignment information

Sergio Lopez <[email protected]> writes:

> There's an increasing number of machines supporting multiple page sizes
> and, on these machines, the host and a guest can be running with
> different pages sizes. In addition to this, there might be physical
> devices that require to operate their memory at a specific granularity.
>
> In these cases, if they are to use Shared Memory Regions, the device
> and the driver must operate with the same granularity, as otherwise
> the former might not be able to fulfill the requests sent by the
> latter.
>
> For the GPU device, this has an impact on blob creation and mapping. To
> address the problem, allow the device to require certain alignment
> constrains for blob resources by extending the device configuration
> with the field "blob_alignment" and introducing the
> VIRTIO_GPU_F_BLOB_ALIGNMENT feature.
>
> Signed-off-by: Sergio Lopez <[email protected]>
> ---
>
> v3:
>  - Add driver conformance statements (thanks Michael).
>  - Avoid using "must" outside conformance statements (thanks Michael).
>  - Elaborate use case in commit description (thanks Michael).
>  - Drop "padding" field requirements (thanks Daniel).
>
> v2:
>  - Clarify blob_alignment valid values (thanks Michael).
>  - Rephrase feature negotiation (thanks Michael).
>
>  conformance.tex                  |  2 ++
>  device-types/gpu/description.tex | 28 ++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+)

Fixes: https://github.com/oasis-tcs/virtio-spec/issues/223
Could you please open a voting ballot for this change?

Thanks,
Sergio.