From: Matthew Auld <matthew.william.auld@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Serge Belyshev <belyshev@depni.sinp.msu.ru>,
Peter Zijlstra <peterz@infradead.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
ML dri-devel <dri-devel@lists.freedesktop.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Intel-gfx] [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot
Date: Mon, 17 May 2021 18:06:44 +0100 [thread overview]
Message-ID: <CAM0jSHPy68kMi8NnpAO7ESVW0Ct=dhZ0kYHJO7APy-GBsNp2fQ@mail.gmail.com> (raw)
In-Reply-To: <20210517131137.GA19451@lst.de>
On Mon, 17 May 2021 at 14:11, Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, May 17, 2021 at 04:09:42PM +0300, Serge Belyshev wrote:
> > Christoph Hellwig <hch@lst.de> writes:
> >
> > > As an ad-hoc experiment: can you replace the call to remap_pfn_range
> > > with remap_pfn_range_notrack (and export it if you build i915 modular)
> > > in remap_io_sg and see if that makes any difference?
> >
> > That worked, thanks -- no artifacts seen.
>
> Looks like it is caused by the validation failure then. Which means the
> existing code is doing something wrong in its choice of the page
> protection bit. I really need help from the i915 maintainers here..
AFAIK there are two users of remap_io_sg, the first is our shmem
objects(see i915_gem_shmem.c), and for these we support UC, WC, and WB
mmap modes for userspace. The other user is device local-memory
objects(VRAM), and for this one we have an actual io_mapping which is
allocated as WC, and IIRC this should only be mapped as WC for the
mmap mode, but normal userspace can't hit this path yet.
What do we need to do here? It sounds like shmem backed objects are
allocated as WB for the pages underneath, but i915 allows mapping them
as UC/WC which trips up this track_pfn thing?
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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next prev parent reply other threads:[~2021-05-17 17:07 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 5:55 [Intel-gfx] add remap_pfn_range_notrack instead of reinventing it in i915 v2 Christoph Hellwig
2021-03-26 5:55 ` [Intel-gfx] [PATCH 1/4] mm: add remap_pfn_range_notrack Christoph Hellwig
2021-03-26 5:55 ` [Intel-gfx] [PATCH 2/4] mm: add a io_mapping_map_user helper Christoph Hellwig
2021-10-20 15:40 ` Lucas De Marchi
2021-10-20 19:37 ` Peter Zijlstra
2021-10-21 6:18 ` Christoph Hellwig
2021-03-26 5:55 ` [Intel-gfx] [PATCH 3/4] i915: use io_mapping_map_user Christoph Hellwig
2021-03-26 5:55 ` [Intel-gfx] [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot Christoph Hellwig
2021-05-08 19:33 ` youling257
2021-05-10 8:58 ` Christoph Hellwig
2021-05-16 16:06 ` Serge Belyshev
2021-05-17 12:37 ` Christoph Hellwig
2021-05-17 13:09 ` Serge Belyshev
2021-05-17 13:11 ` Christoph Hellwig
2021-05-17 17:06 ` Matthew Auld [this message]
2021-05-18 13:21 ` Christoph Hellwig
2021-05-18 15:00 ` Matthew Auld
2021-05-19 5:46 ` Thomas Hellström (Intel)
2021-05-17 21:46 ` Thomas Hellström
2021-05-18 6:46 ` Thomas Hellström
2021-05-18 13:24 ` Christoph Hellwig
2021-05-18 13:33 ` Thomas Hellström
2021-05-18 13:23 ` Christoph Hellwig
2021-05-19 5:51 ` Thomas Hellström
2021-03-26 7:28 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/4] mm: add remap_pfn_range_notrack Patchwork
2021-03-26 7:31 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-03-26 7:34 ` [Intel-gfx] ✗ Fi.CI.DOCS: " Patchwork
2021-03-26 7:59 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
2021-04-08 10:36 ` [Intel-gfx] add remap_pfn_range_notrack instead of reinventing it in i915 v2 Daniel Vetter
2021-04-08 11:28 ` Christoph Hellwig
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