Re: [dpdk-dev] [PATCH] vfio: fix expanding DMA area in ppc64le

[Aaron Conole <aconole@redhat.com>]

Takeshi Yoshimura <tyos@jp.ibm.com> writes:

> In ppc64le, expanding DMA areas always fail because we cannot remove
> a DMA window. As a result, we cannot allocate more than one memseg in
> ppc64le. This is because vfio_spapr_dma_mem_map() doesn't unmap all
> the mapped DMA before removing the window. This patch fixes this
> incorrect behavior.
>
> I added a global variable to track current window size since we do
> not have better ways to get exact size of it than doing so. sPAPR
> IOMMU seems not to provide any ways to get window size with ioctl
> interfaces. rte_memseg_walk*() is currently used to calculate window
> size, but it walks memsegs that are marked as used, not mapped. So,
> we need to determine if a given memseg is mapped or not, otherwise
> the ioctl reports errors due to attempting to unregister memory
> addresses that are not registered. The global variable is excluded
> in non-ppc64le binaries.
>
> Similar problems happen in user maps. We need to avoid attempting to
> unmap the address that is given as the function's parameter. The
> compaction of user maps prevents us from passing correct length for
> unmapping DMA at the window recreation. So, I removed it in ppc64le.
>
> I also fixed the order of ioctl for unregister and unmap. The ioctl
> for unregister sometimes report device busy errors due to the
> existence of mapped area.
>
> Signed-off-by: Takeshi Yoshimura <tyos@jp.ibm.com>
> ---

Hi Takeshi,

I see the compilation with this patch has failed.

See https://travis-ci.com/ovsrobot/dpdk/builds/115206950 for the jobs
run.