From: Christoph Hellwig <hch@infradead.org>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: kvm@vger.kernel.org, David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org,
Bjorn Andersson <bjorn.andersson@linaro.org>,
linux-tegra@vger.kernel.org, Julien Grall <julien.grall@arm.com>,
Will Deacon <will@kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
linux-samsung-soc@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-rockchip@lists.infradead.org,
Andy Gross <agross@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
virtualization@lists.linux-foundation.org,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
David Woodhouse <dwmw2@infradead.org>,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, Tom Murphy <murphyt7@tcd.ie>,
iommu@lists.linux-foundation.org, Kukjin Kim <kgene@kernel.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [Intel-gfx] [PATCH 0/8] Convert the intel iommu driver to the dma-iommu api
Date: Fri, 29 May 2020 05:45:23 -0700 [thread overview]
Message-ID: <20200529124523.GA11817@infradead.org> (raw)
In-Reply-To: <465815ae-9292-f37a-59b9-03949cb68460@deltatee.com>
On Thu, May 28, 2020 at 06:00:44PM -0600, Logan Gunthorpe wrote:
> > This issue is most likely in the i915 driver and is most likely caused by the driver not respecting the return value of the dma_map_ops::map_sg function. You can see the driver ignoring the return value here:
> > https://github.com/torvalds/linux/blob/7e0165b2f1a912a06e381e91f0f4e495f4ac3736/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c#L51
> >
> > Previously this didn’t cause issues because the intel map_sg always returned the same number of elements as the input scatter gather list but with the change to this dma-iommu api this is no longer the case. I wasn’t able to track the bug down to a specific line of code unfortunately.
Mark did a big audit into the map_sg API abuse and initially had
some i915 patches, but then gave up on them with this comment:
"The biggest TODO is DRM/i915 driver and I don't feel brave enough to fix
it fully. The driver creatively uses sg_table->orig_nents to store the
size of the allocate scatterlist and ignores the number of the entries
returned by dma_map_sg function. In this patchset I only fixed the
sg_table objects exported by dmabuf related functions. I hope that I
didn't break anything there."
it would be really nice if the i915 maintainers could help with sorting
that API abuse out.
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2020-05-29 14:03 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-21 15:03 [Intel-gfx] [PATCH 0/8] Convert the intel iommu driver to the dma-iommu api Tom Murphy
2019-12-21 15:03 ` [Intel-gfx] [PATCH 1/8] iommu/vt-d: clean up 32bit si_domain assignment Tom Murphy
2019-12-21 23:46 ` Arvind Sankar
2019-12-23 3:00 ` Lu Baolu
2019-12-21 15:03 ` [Intel-gfx] [PATCH 2/8] iommu/vt-d: Use default dma_direct_* mapping functions for direct mapped devices Tom Murphy
2019-12-21 15:03 ` [Intel-gfx] [PATCH 3/8] iommu/vt-d: Remove IOVA handling code from non-dma_ops path Tom Murphy
2020-03-20 6:30 ` Tom Murphy
2020-03-20 7:06 ` Lu Baolu
2019-12-21 15:03 ` [Intel-gfx] [PATCH 4/8] iommu: Handle freelists when using deferred flushing in iommu drivers Tom Murphy
2019-12-21 15:03 ` [Intel-gfx] [PATCH 5/8] iommu: Add iommu_dma_free_cpu_cached_iovas function Tom Murphy
2019-12-21 15:03 ` [Intel-gfx] [PATCH 6/8] iommu: allow the dma-iommu api to use bounce buffers Tom Murphy
2019-12-24 10:20 ` kbuild test robot
2019-12-21 15:03 ` [Intel-gfx] [PATCH 7/8] iommu/vt-d: Convert intel iommu driver to the iommu ops Tom Murphy
2019-12-21 15:04 ` [Intel-gfx] [PATCH 8/8] DO NOT MERGE: iommu: disable list appending in dma-iommu Tom Murphy
2019-12-22 2:43 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for Convert the intel iommu driver to the dma-iommu api Patchwork
2019-12-22 3:12 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
2019-12-23 10:37 ` [Intel-gfx] [PATCH 0/8] " Jani Nikula
2019-12-23 11:29 ` Robin Murphy
2019-12-23 11:41 ` Jani Nikula
2020-03-20 6:28 ` Tom Murphy
2020-05-29 0:00 ` Logan Gunthorpe
2020-05-29 12:45 ` Christoph Hellwig [this message]
2020-05-29 19:05 ` Logan Gunthorpe
2020-05-29 21:11 ` Marek Szyprowski
2020-05-29 21:21 ` Logan Gunthorpe
2020-08-24 0:04 ` Tom Murphy
2020-08-26 18:26 ` Alex Deucher
2020-08-27 21:36 ` Logan Gunthorpe
2020-08-27 23:34 ` Tom Murphy
2020-09-03 20:26 ` Tom Murphy
2020-09-08 15:28 ` Tvrtko Ursulin
2020-09-08 15:44 ` Logan Gunthorpe
2020-09-08 15:56 ` Tvrtko Ursulin
2020-09-08 22:43 ` Tom Murphy
2020-09-09 9:16 ` Tvrtko Ursulin
2020-09-09 12:55 ` Tvrtko Ursulin
2020-09-10 13:33 ` Tom Murphy
2020-09-10 13:34 ` Tom Murphy
2020-08-26 18:14 ` Robin Murphy
2020-08-26 18:23 ` Tom Murphy
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