From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: jean-philippe@linaro.org, will@kernel.org, linux-mm@kvack.org,
Linux IOMMU <iommu@lists.linux-foundation.org>,
Thierry Reding <thierry.reding@gmail.com>,
Ajay kumar <ajaynumb@gmail.com>,
Shaik Ameer Basha <shaik.ameer@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
hch@lst.de
Subject: Re: IOVA allocation dependency between firmware buffer and remaining buffers
Date: Thu, 24 Sep 2020 10:46:46 +0200 [thread overview]
Message-ID: <37e767b8-8ec4-ae80-ea0d-1caf3cdab8fa@samsung.com> (raw)
In-Reply-To: <20200924082830.GB27174@8bytes.org>
Hi Joerg,
On 24.09.2020 10:28, Joerg Roedel wrote:
> On Wed, Sep 23, 2020 at 08:48:26AM +0200, Marek Szyprowski wrote:
>> It allows to remap given buffer at the specific IOVA address, although
>> it doesn't guarantee that those specific addresses won't be later used
>> by the IOVA allocator. Probably it would make sense to add an API for
>> generic IOMMU-DMA framework to mark the given IOVA range as
>> reserved/unused to protect them.
> There is an API for that, the IOMMU driver can return IOVA reserved
> regions per device and the IOMMU core code will take care of mapping
> these regions and reserving them in the IOVA allocator, so that
> DMA-IOMMU code will not use it for allocations.
>
> Have a look at the iommu_ops->get_resv_regions() and
> iommu_ops->put_resv_regions().
I know about the reserved regions IOMMU API, but the main problem here,
in case of Exynos, is that those reserved regions won't be created by
the IOMMU driver but by the IOMMU client device. It is just a result how
the media drivers manages their IOVA space. They simply have to load
firmware at the IOVA address lower than the any address of the used
buffers.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-09-24 8:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 15:54 IOVA allocation dependency between firmware buffer and remaining buffers Ajay kumar
2020-04-24 15:04 ` Ajay kumar
2020-04-24 15:29 ` Robin Murphy
2020-04-24 16:15 ` Shaik Ameer Basha
2020-09-23 6:48 ` Marek Szyprowski
2020-09-23 6:58 ` Christoph Hellwig
2020-09-23 7:45 ` Ajay kumar
2020-09-23 13:47 ` Christoph Hellwig
2020-09-23 8:25 ` Ajay Kumar
2020-09-24 8:28 ` Joerg Roedel
2020-09-24 8:46 ` Marek Szyprowski [this message]
2020-09-24 10:16 ` Thierry Reding
2020-09-24 10:40 ` Robin Murphy
2020-09-24 10:47 ` Marek Szyprowski
2020-09-24 11:06 ` Robin Murphy
2020-09-24 14:14 ` Shaik Ameer Basha
2020-09-28 6:52 ` Marek Szyprowski
2020-09-24 10:41 ` Marek Szyprowski
2020-09-24 14:33 ` Thierry Reding
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=37e767b8-8ec4-ae80-ea0d-1caf3cdab8fa@samsung.com \
--to=m.szyprowski@samsung.com \
--cc=ajaynumb@gmail.com \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=jean-philippe@linaro.org \
--cc=joro@8bytes.org \
--cc=linux-mm@kvack.org \
--cc=robin.murphy@arm.com \
--cc=shaik.ameer@samsung.com \
--cc=thierry.reding@gmail.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).