From: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>,
Jonathan Hunter
<jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: [PATCH v1 2/4] iommu/tegra: gart: Check whether page is already mapped
Date: Tue, 26 Sep 2017 16:49:52 +0300 [thread overview]
Message-ID: <e59eb818-4edf-f3a2-947a-bc21507b0b85@gmail.com> (raw)
In-Reply-To: <20170926110636.GA23108@ulmo>
On 26.09.2017 14:06, Thierry Reding wrote:
> On Wed, Jul 05, 2017 at 07:29:46PM +0300, Dmitry Osipenko wrote:
>> Due to a bug, multiple devices may try to map the same IOVA region. We can
>> catch that case by checking that 'VALID' bit of the GART's page entry is
>> unset prior to mapping of the page.
>
> Due to what bug? Sounds to me like access to the GART should be
> exclusive, so that only a single driver can ever access it.
>
Actually, there are a lot of peripherals behind the GART. But yes, probably we
would use it exclusively for the GPU allocations.
In a case of the GPU allocations there could be a bug in the allocation code
(drm_mm_scan) that would cause re-mapping of the already mapped pages, we would
be able to catch such a bug.
--
Dmitry
next prev parent reply other threads:[~2017-09-26 13:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-05 16:29 [PATCH v1 0/4] iommu/tegra: gart: Couple corrections Dmitry Osipenko
[not found] ` <cover.1499270277.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-07-05 16:29 ` [PATCH v1 1/4] iommu/tegra: gart: Don't unnecessarily allocate registers context Dmitry Osipenko
[not found] ` <df570fb6649da6bc3b5f2a68afcb5471e6148269.1499270277.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-26 11:19 ` Thierry Reding
2017-09-26 14:15 ` Dmitry Osipenko
2017-07-05 16:29 ` [PATCH v1 2/4] iommu/tegra: gart: Check whether page is already mapped Dmitry Osipenko
[not found] ` <a19ba1ca835aa2526d2c0492e6b0d0b35889596a.1499270277.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-26 11:06 ` Thierry Reding
2017-09-26 13:49 ` Dmitry Osipenko [this message]
[not found] ` <e59eb818-4edf-f3a2-947a-bc21507b0b85-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-26 16:07 ` Thierry Reding
2017-09-26 16:57 ` Dmitry Osipenko
2017-07-05 16:29 ` [PATCH v1 3/4] iommu/tegra: gart: Move PFN validation out of spinlock Dmitry Osipenko
[not found] ` <301b5e91fae43beae4542e8c4a7d5ca6a6918ba0.1499270277.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-26 11:07 ` Thierry Reding
2017-07-05 16:29 ` [PATCH v1 4/4] iommu/tegra: gart: Correct number of unmapped bytes Dmitry Osipenko
[not found] ` <f30500403195b029ee236fff3b3c6f0b4dc60cbb.1499270277.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-26 11:09 ` Thierry Reding
2017-07-25 14:43 ` [PATCH v1 0/4] iommu/tegra: gart: Couple corrections Joerg Roedel
[not found] ` <20170725144335.GC30429-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2017-07-29 11:04 ` Dmitry Osipenko
[not found] ` <430af3ab-29cd-bbe8-087d-82d8113d2a89-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-07-29 11:09 ` Dmitry Osipenko
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