Enhance RPMsg buffer management

[RFC PATCH 0/2] Enhance RPMsg buffer management

Posted by Tanmay Shah 2 months, 3 weeks ago

Take rx and tx buffer size from virtio device config space in the
resource table. This allows each firmware to configure RPMsg buffer size
as needed in each direction.

Original seris:
https://lore.kernel.org/all/1548949280-31794-1-git-send-email-xiaoxiang@xiaomi.com/

Following modificaitons are done to the original series:
  - Separate dma allocation is not done for tx and rx buffers. Instead
    allocated chunk of memory is split between tx and rx buffers.
  - If vdev doesn't support VIRTIO_RPMSG_F_BUFSZ feature then use the 
    default size of 512 bytes for buffers
  - Change MAX_RPMSG_BUF_SIZE to DEFAULT_RPMSG_BUF_SIZE
  - move virtio_rpmsg.h from uapi to linux dir
  - RPMsg buffer size must be set to hold rpmsg header at minimum in the
    vdev config space of the firmware.
  - align total buf size to page size when allocating and deallocating
    memory

Xiang Xiao (2):
  rpmsg: virtio_rpmsg_bus: allow the different vring size for send/recv
  rpmsg: virtio_rpmsg_bus: get buffer size from config space

 drivers/rpmsg/virtio_rpmsg_bus.c | 105 ++++++++++++++++++++-----------
 include/linux/virtio_rpmsg.h     |  24 +++++++
 2 files changed, 93 insertions(+), 36 deletions(-)
 create mode 100644 include/linux/virtio_rpmsg.h


base-commit: f982fbb1a6ca3553c15763ad9eb2beeae78d3684
-- 
2.34.1

Re: [RFC PATCH 0/2] Enhance RPMsg buffer management

Posted by Mathieu Poirier 1 month, 3 weeks ago

On Fri, Nov 14, 2025 at 10:46:38AM -0800, Tanmay Shah wrote:
> Take rx and tx buffer size from virtio device config space in the
> resource table. This allows each firmware to configure RPMsg buffer size
> as needed in each direction.
> 
> Original seris:
> https://lore.kernel.org/all/1548949280-31794-1-git-send-email-xiaoxiang@xiaomi.com/
> 
> Following modificaitons are done to the original series:
>   - Separate dma allocation is not done for tx and rx buffers. Instead
>     allocated chunk of memory is split between tx and rx buffers.
>   - If vdev doesn't support VIRTIO_RPMSG_F_BUFSZ feature then use the 
>     default size of 512 bytes for buffers
>   - Change MAX_RPMSG_BUF_SIZE to DEFAULT_RPMSG_BUF_SIZE
>   - move virtio_rpmsg.h from uapi to linux dir
>   - RPMsg buffer size must be set to hold rpmsg header at minimum in the
>     vdev config space of the firmware.
>   - align total buf size to page size when allocating and deallocating
>     memory
> 
> Xiang Xiao (2):
>   rpmsg: virtio_rpmsg_bus: allow the different vring size for send/recv
>   rpmsg: virtio_rpmsg_bus: get buffer size from config space
> 
>  drivers/rpmsg/virtio_rpmsg_bus.c | 105 ++++++++++++++++++++-----------
>  include/linux/virtio_rpmsg.h     |  24 +++++++
>  2 files changed, 93 insertions(+), 36 deletions(-)
>  create mode 100644 include/linux/virtio_rpmsg.h
>

This set is going somewhere.  Please address the comments that were received and
send a new revision.

Apologies for the long review delay.
Mathieu
 
> 
> base-commit: f982fbb1a6ca3553c15763ad9eb2beeae78d3684
> -- 
> 2.34.1
>

Re: [RFC PATCH 0/2] Enhance RPMsg buffer management

Posted by Tanmay Shah 1 month, 3 weeks ago


On 12/17/25 3:31 PM, Mathieu Poirier wrote:
> On Fri, Nov 14, 2025 at 10:46:38AM -0800, Tanmay Shah wrote:
>> Take rx and tx buffer size from virtio device config space in the
>> resource table. This allows each firmware to configure RPMsg buffer size
>> as needed in each direction.
>>
>> Original seris:
>> https://lore.kernel.org/all/1548949280-31794-1-git-send-email-xiaoxiang@xiaomi.com/
>>
>> Following modificaitons are done to the original series:
>>   - Separate dma allocation is not done for tx and rx buffers. Instead
>>     allocated chunk of memory is split between tx and rx buffers.
>>   - If vdev doesn't support VIRTIO_RPMSG_F_BUFSZ feature then use the 
>>     default size of 512 bytes for buffers
>>   - Change MAX_RPMSG_BUF_SIZE to DEFAULT_RPMSG_BUF_SIZE
>>   - move virtio_rpmsg.h from uapi to linux dir
>>   - RPMsg buffer size must be set to hold rpmsg header at minimum in the
>>     vdev config space of the firmware.
>>   - align total buf size to page size when allocating and deallocating
>>     memory
>>
>> Xiang Xiao (2):
>>   rpmsg: virtio_rpmsg_bus: allow the different vring size for send/recv
>>   rpmsg: virtio_rpmsg_bus: get buffer size from config space
>>
>>  drivers/rpmsg/virtio_rpmsg_bus.c | 105 ++++++++++++++++++++-----------
>>  include/linux/virtio_rpmsg.h     |  24 +++++++
>>  2 files changed, 93 insertions(+), 36 deletions(-)
>>  create mode 100644 include/linux/virtio_rpmsg.h
>>
> 
> This set is going somewhere.  Please address the comments that were received and
> send a new revision.
> 
> Apologies for the long review delay.
> Mathieu
>  

Sure Mathieu, no problem. I will be on leave in the January, and will start
working on this patch series once I come back.

Thanks,
Tanmay

>>
>> base-commit: f982fbb1a6ca3553c15763ad9eb2beeae78d3684
>> -- 
>> 2.34.1
>>