Re: [dpdk-dev] [PATCH] doc: announce change in dma mapping/unmapping

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 25-Aug-21 12:27 PM, Xuan Ding wrote:
> Currently, the VFIO subsystem will compact adjacent DMA regions for the
> purposes of saving space in the internal list of mappings. This has a
> side effect of compacting two separate mappings that just happen to be
> adjacent in memory. Since VFIO implementation on IA platforms also does
> not allow partial unmapping of memory mapped for DMA, the current DPDK
> VFIO implementation will prevent unmapping of accidentally adjacent
> maps even though it could have been unmapped [1].
> 
> The proper fix for this issue is to change the VFIO DMA mapping API to
> also include page size, and always map memory page-by-page.
> 
> [1] https://mails.dpdk.org/archives/dev/2021-July/213493.html
> 
> Signed-off-by: Xuan Ding <xuan.ding@intel.com>
> ---
>   doc/guides/rel_notes/deprecation.rst | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 76a4abfd6b..272ffa993e 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -287,3 +287,6 @@ Deprecation Notices
>     reserved bytes to 2 (from 3), and use 1 byte to indicate warnings and other
>     information from the crypto/security operation. This field will be used to
>     communicate events such as soft expiry with IPsec in lookaside mode.
> +
> +  * vfio: the functions `rte_vfio_container_dma_map` and `rte_vfio_container_dma_unmap`
> +  will be amended to include page size. This change is targeted for DPDK 21.11.
> 

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly