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.d...@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. -- 2.17.1
