[dpdk-dev] [PATCH] vfio: support iommu group zero

Thomas Monjalon thomas.monjalon at 6wind.com
Wed Dec 9 23:49:59 CET 2015


2015-12-09 13:58, Stephen Hemminger:
> On Wed, 09 Dec 2015 22:12:33 +0100
> Thomas Monjalon <thomas.monjalon at 6wind.com> wrote:
> 
> > 2015-12-09 09:55, Stephen Hemminger:
> > > The current implementation of VFIO will not with the new no-IOMMU mode
> > > in 4.4 kernel. The original code assumed that IOMMU group zero would
> > > never be used. Group numbers are assigned starting at zero, and up
> > > until now the group numbers came from the hardware which is likely
> > > to use group 0 for system devices that are not used with DPDK.
> > > 
> > > The fix is to allow 0 as a valid group and rearrange code
> > > to split the return value from the group value.
> > > 
> > > Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> > > ---
> > > Why was this ignored? It was originally sent on 26 Oct 15 back
> > > when IOMMU discussion was lively.
> > 
> > There was no review of this patch.
> > The patch has been marked as deferred recently when it was too late
> > to do such feature changes in DPDK code:
> > 	http://dpdk.org/dev/patchwork/patch/8035/
> 
> This is why as a fallback the MAINTAINER has to review the patch
> or direct a sub-maintainer to do it. I think almost 2 months is
> plenty of time for review.

27 October was 3 days before the feature deadline.
And you have not pinged about it since then.
But that's true I have missed the importance of this patch.
Would it help to have it integrated today?
Are you sure it won't break something else?



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