From: Julien Grall <julien@xen.org>
To: Roman Skakun <rm.skakun@gmail.com>,
Stefano Stabellini <sstabellini@kernel.org>,
xen-devel@lists.xenproject.org
Cc: Roman Skakun <roman_skakun@epam.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Andrii Anisov <andrii_anisov@epam.com>
Subject: Re: [RFC 1/1] xen/arm: set iommu property for IOMMU-protected devices
Date: Mon, 8 Nov 2021 18:30:36 +0000 [thread overview]
Message-ID: <17547d29-8e15-96f6-2418-5f7ca1c3237d@xen.org> (raw)
In-Reply-To: <5b101e4e85668bbb18da83044520b0350344f408.1633106362.git.roman_skakun@epam.com>
Hi Roman,
On 04/10/2021 10:54, Roman Skakun wrote:
> From: Roman Skakun <roman_skakun@epam.com>
>
> Xen is not exposing any IOMMU properties to Dom0.
> So Dom0 assumes that all it's devices are not protected by IOMMU.
>
> To make Dom0 aware of IOMMU-protected devices, we need to mark
> them somehow. With this approach Dom0 Linux kernel will be able
> to selectively disable swiotlb-xen fops for them which will remove
> unnecessary buffer bounces.
>
> This patch adds mechanism to describe IOMMU-protected devices by
> adding `xen,behind-iommu` property to relevant device nodes in
> Dom0 device tree.
A few years ago, I attempted to disable the swiotlb when Xen configured
the IOMMU for the device (see [1]). Did you have a chance to go through
the thread? In particular, I think Ian Campbell suggestion about
creating an IOMMU binding is quite interesting.
Stefano, what do you think?
Cheers,
[1]
https://patchwork.ozlabs.org/project/devicetree-bindings/patch/1392913301-25524-1-git-send-email-julien.grall@linaro.org/
--
Julien Grall
next prev parent reply other threads:[~2021-11-08 18:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 9:54 [RFC 0/1] tag IOMMU-protected devices in Dom0 fdt Roman Skakun
2021-10-04 9:54 ` [RFC 1/1] xen/arm: set iommu property for IOMMU-protected devices Roman Skakun
2021-10-06 12:45 ` Oleksandr
2021-10-07 11:04 ` Roman Skakun
2021-11-08 18:30 ` Julien Grall [this message]
2021-11-10 21:12 ` Stefano Stabellini
2021-12-07 15:40 ` Sergiy Kibrik
2021-12-10 2:04 ` Stefano Stabellini
2021-10-04 9:54 ` [RFC PATCH] dma-mapping: don't set swiotlb-xen fops " Roman Skakun
2021-10-12 14:11 ` [RFC 0/1] tag IOMMU-protected devices in Dom0 fdt Roman Skakun
2021-10-12 14:20 ` Julien Grall
2021-10-12 14:23 ` Roman Skakun
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=17547d29-8e15-96f6-2418-5f7ca1c3237d@xen.org \
--to=julien@xen.org \
--cc=Volodymyr_Babchuk@epam.com \
--cc=andrii_anisov@epam.com \
--cc=rm.skakun@gmail.com \
--cc=roman_skakun@epam.com \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.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).