Re: [PATCH] iommu/vt-d: Fix scatterlist offset handling

From: Raj, Ashok
Date: Thu Nov 16 2017 - 16:44:50 EST

Hi Alex

On Thu, Nov 16, 2017 at 02:32:44PM -0700, Alex Williamson wrote:
> On Wed, 15 Nov 2017 15:54:56 -0800
> Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> wrote:
> > Hi Alex and all,
> >
> > Just wondering if you could merge Robin's patch for the next rc. From
> > all our testing, this seems to be a solid fix and should be included in
> > the stable releases as well.
> Hi Jacob,
> Sorry, this wasn't on my radar, I only scanned for patches back through
> about when Joerg refreshed his next branch (others on the list speak up
> if I didn't pickup your patches for the v4.15 merge window).
> This patch makes sense to me and I'm glad you were able to work through
> the anomaly Harsh saw in testing as an unrelated issue, but...
> What do we do about this? I certainly can't rip out large page support
> and put a stable tag on the patch. I'm not really spotting what's
> wrong with large page support here, other than the comment about it
> being a mess. Suggestions? Thanks,

Largepage seems to work and i don't think we need to rip it out. When
Harsh tested it at one point we thought disabling super-page seemed to make
the problem go away. Jacob tested and we still saw the need for Robin's patch.

Yes, the function looks humongous but i don't think we should wait for that
before this merge.