Re: [PATCH v8 0/5] Enhance RPMsg buffer management

[Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>]

On 8/28/26 16:58, Tanmay Shah wrote:
> Current design uses fixed (512 bytes) rpmsg buffer size in both rx and
> tx directions. This design is not suitable if the payload is larger than
> 512 bytes or the payload is very small and doesn't need that much
> memory. Instead introduce new virtio feature to retrieve rpmsg tx buf
> size and rx buf size from the virtio config space in the resource table.

This version seems good to me, with or without my suggestion in patch 4/5

Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

Thanks!

Arnaud

> 
> Changes in v8:
>    - fix commit message of 3/5, "%s/enable/Enabled"
>    - introduce new function to get buffer size for the vdev device
>    - fix description of VIRTIO_RPMSG_F_BUFSZ define
>    - "%s/or differnt RX and TX sizes)/or different RX and TX queue sizes)/"
> 
> Changes in v7:
>    - Fix 5/5 commit text, and move change log out of commit text
> 
> Changes in v6:
>    - remove buffer alignment from config space
>    - rpmsg.rst: modify alignment related documentation
> 
> Changes in v5:
>    - fix documentation about alignment of the buffer size
>    - change version field from u16 to u8
>    - remove buffer alignment check
>    - Separate buffer alignment vs MTU of a single buffer
>    - Use buffer alignment only to get next buffer address at alignment
>      boundary
> 
> Changes in v4:
>    - Introduce new patch to modify rpmsg.rst documentation
>    - check version is always 1.
>    - check size field is same as size of struct virtio_rpmsg_config
>    - introduce alignment field
>    - check alignment field is power of 2
>    - check tx and rx buf size is aligned with alignment passed in the
>      structure
>    - check msg size is < MTU size
> 
> Changes in v3:
>    - new patch [1/4] that renames variables with clear names.
>    - %s/rbufs/rx_bufs/
>    - %s/sbufs/tx_bufs/
>    - %s/last_sbuf/last_tx_buf/
>    - add num_rx_buf and num_tx_buf in the documentation
>    - change version field from u16 to u8
>    - introduce size field in the rpmsg_virtio_config structure
>    - check version field is set to any non-zero value.
>    - check size field is not 0.
>    - Remove field for private config, as not needed for now.
>    - add documentation of rpmsg_virtio_config structure
>    - Check for error when retrieving MTU size in the sample driver
>    - %s/mtu/MTU/
> 
> Changes in v2:
>    - Change author
>    - fix commit message with better explanation
>    - %s/sbuf/tx_buf
>    - %s/rbuf/rx_buf
>    - %s/num_rbuf/num_rx_buf/
>    - %s/num_sbuf/num_tx_buf/
>    - %s/sbuf_size/tx_buf_size/
>    - %s/rbuf_size/rx_buf_size/
>    - fix typo
>    - do not use ALIGN on buf size, rely on allocator
>    - make err msg more explicit, %s/vdev config:/bad vdev config/
>    - fix license and add AMD copyrights in the header virtio_rpmsg.h
>    - Assign bit 1 to VIRTIO_RPMSG_F_BUFSZ feature
>    - use __virtio32 over __u32
>    - add version field to virtio rpmsg config structure
>    - Introduce new patch to print rpmsg mtu size in the sample rpmsg driver
>    - move linux/virtio_rpmsg.h to linux/rpmsg/virtio_rpmsg.h
> 
> 
> Tanmay Shah (5):
>    rpmsg: virtio_rpmsg_bus: rename rbufs and sbufs
>    rpmsg: virtio_rpmsg_bus: allow different size of tx and rx bufs
>    rpmsg: virtio_rpmsg_bus: get buffer size from config space
>    docs: rpmsg: add virtio config space details
>    samples: rpmsg: add MTU size info
> 
>   Documentation/staging/rpmsg.rst     |  17 +++
>   drivers/rpmsg/virtio_rpmsg_bus.c    | 156 +++++++++++++++++++---------
>   include/linux/rpmsg/virtio_rpmsg.h  |  41 ++++++++
>   samples/rpmsg/rpmsg_client_sample.c |  20 +++-
>   4 files changed, 186 insertions(+), 48 deletions(-)
>   create mode 100644 include/linux/rpmsg/virtio_rpmsg.h
> 
> 
> base-commit: d4d61a4b0a52e8f3cdb3e1578602850a3452ec3e