From: Joerg Roedel <joro@8bytes.org>
To: "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>
Subject: Re: [PATCH] iommu: Remove functions that support private domain
Date: Thu, 14 May 2020 21:56:15 +0200 [thread overview]
Message-ID: <20200514195615.GP18353@8bytes.org> (raw)
In-Reply-To: <FFF73D592F13FD46B8700F0A279B802F573A651E@ORSMSX114.amr.corp.intel.com>
On Thu, May 14, 2020 at 06:44:16PM +0000, Prakhya, Sai Praneeth wrote:
> Could you please explain why we shouldn't change default-domain for an
> iommu group that has multiple devices?
Because you can't be sure that a device is bound to a driver while the
default domain of the group is changed. As long as this race condition
exists we can't change the default domains of groups with multiple
devices at runtime.
> I am asking this particularly because the patch set I am working on
> allows to change default-domain for an iommu group that has multiple
> devices. The pre-requisite being that all the devices in the group
> should already be unbounded from the device driver and the
> default-domain preferences of all the devices in the group shouldn't
> have conflicting types i.e. some devices cannot say they *only* need
> identity domain while other devices in the same group say that they
> *only* need to be in DMA domain. In this case, we will not be able to
> decide upon a default-domain for the iommu group.
Yeah, but as I wrote above, this is racy and there is currently no way
to fix that. So we can't support it.
Regards,
Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-05-14 19:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 22:47 [PATCH] iommu: Remove functions that support private domain Sai Praneeth Prakhya
2020-05-14 13:13 ` Joerg Roedel
2020-05-14 17:51 ` Prakhya, Sai Praneeth
2020-05-14 18:32 ` Joerg Roedel
2020-05-14 18:44 ` Prakhya, Sai Praneeth
2020-05-14 19:56 ` Joerg Roedel [this message]
2020-05-14 23:12 ` Prakhya, Sai Praneeth
2020-05-15 9:59 ` Joerg Roedel
2020-05-15 12:55 ` Lu Baolu
2020-05-15 15:46 ` Joerg Roedel
2020-05-17 8:29 ` Prakhya, Sai Praneeth
2020-05-25 13:56 ` Joerg Roedel
2020-05-28 19:31 ` Prakhya, Sai Praneeth
2020-05-15 18:35 ` Prakhya, Sai Praneeth
2020-05-15 10:01 ` Joerg Roedel
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=20200514195615.GP18353@8bytes.org \
--to=joro@8bytes.org \
--cc=iommu@lists.linux-foundation.org \
--cc=sai.praneeth.prakhya@intel.com \
/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).