From: Joerg Roedel <joro@8bytes.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>,
Will Deacon <will.deacon@arm.com>,
iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH V2 3/5] iommu: Add support to change default domain of an iommu_group
Date: Tue, 3 Mar 2020 14:13:27 +0100 [thread overview]
Message-ID: <20200303131326.GB13185@8bytes.org> (raw)
In-Reply-To: <7fcadd2a-76cd-2114-bb5f-c916fd14e1cb@linux.intel.com>
Hi Baolu,
On Tue, Mar 03, 2020 at 02:47:02PM +0800, Lu Baolu wrote:
> Theoretically speaking, per-device default domain is impractical. PCI
> aliased devices (PCI bridge and all devices beneath it, VMD devices and
> various devices quirked with pci_add_dma_alias()) must use the same
> domain. It's likely that we have to introduce something like a sub-group
> with all PCI aliased devices staying in it. Current private-domain
> implementation in the vt-d driver was introduced for compatible purpose
> and I wanted to abandon it from the first day. :-)
What hinders you from removing it now? I looked a bit closer into
these private default domain implementation and it is very fragile. If
it can be removed, then better do so sooner than later.
> Probably, we are able to configure per-group default domain type with
> below two interfaces.
>
> - (ops->)dev_def_domain_type: Return the required default domain type
> for a device. It returns
> - IOMMU_DOMAIN_DMA (device must use a DMA domain), unlikely
> - IOMMU_DOMAIN_IDENTITY (device must use an Identity domain), unlikely
> - 0 (both are okay), likely
If we stay at the group level, this interface should work on the group
level too, and not on the device level.
> - iommu_group_change_def_domain: Change the default domain of a group
> Works only when all devices have no driver bond.
Btw, I have no objections about the concept of private default domains
for devices, but the implementation should be moved to generic IOMMU
code so that the behavior is consistent accross differnet IOMMU
platforms, and of course be robust.
Regards,
Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-03-03 13:13 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-16 21:57 [PATCH V2 0/5] iommu: Add support to change default domain of a group Sai Praneeth Prakhya
2020-02-16 21:57 ` [PATCH V2 1/5] iommu: Add dev_def_domain_type() call back function to iommu_ops Sai Praneeth Prakhya
2020-02-22 23:37 ` Lu Baolu
2020-02-22 23:39 ` Prakhya, Sai Praneeth
2020-02-16 21:57 ` [PATCH V2 2/5] iommu/vt-d: Rename device_def_domain_type() to intel_iommu_dev_def_domain_type() Sai Praneeth Prakhya
2020-02-22 23:42 ` Lu Baolu
2020-02-22 23:59 ` Prakhya, Sai Praneeth
2020-02-23 1:50 ` Lu Baolu
2020-02-24 3:23 ` Prakhya, Sai Praneeth
2020-02-16 21:57 ` [PATCH V2 3/5] iommu: Add support to change default domain of an iommu_group Sai Praneeth Prakhya
2020-02-23 1:20 ` Lu Baolu
2020-02-24 3:20 ` Prakhya, Sai Praneeth
2020-02-24 5:46 ` Lu Baolu
2020-02-24 7:03 ` Prakhya, Sai Praneeth
2020-02-24 7:39 ` Lu Baolu
2020-02-24 7:57 ` Prakhya, Sai Praneeth
2020-02-24 8:12 ` Lu Baolu
2020-02-24 8:39 ` Lu Baolu
2020-02-24 8:44 ` Prakhya, Sai Praneeth
2020-03-02 15:08 ` Joerg Roedel
2020-03-03 6:47 ` Lu Baolu
2020-03-03 13:13 ` Joerg Roedel [this message]
2020-03-04 12:17 ` Lu Baolu
2020-02-16 21:57 ` [PATCH V2 4/5] iommu: Take lock before reading iommu_group default domain type Sai Praneeth Prakhya
2020-02-16 21:57 ` [PATCH V2 5/5] iommu: Document usage of "/sys/kernel/iommu_groups/<grp_id>/type" file Sai Praneeth Prakhya
2020-02-23 1:38 ` Lu Baolu
2020-02-24 2:18 ` Prakhya, Sai Praneeth
2020-02-22 23:40 ` [PATCH V2 0/5] iommu: Add support to change default domain of a group Prakhya, Sai Praneeth
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=20200303131326.GB13185@8bytes.org \
--to=joro@8bytes.org \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=robin.murphy@arm.com \
--cc=will.deacon@arm.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).