[dpdk-dev] [PATCH] doc: announce change in vfio dma mapping

Ferruh Yigit ferruh.yigit at intel.com
Tue Aug 31 18:01:28 CEST 2021


On 8/31/2021 2:10 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 at 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..1234420caf 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` will be amended to
> +  include page size. This change is targeted for DPDK 22.02.
> 

Is this means adding a new parameter to API?
If so this is an ABI/API break and we can't do this change in the 22.02.


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