From: Christoph Hellwig <hch@lst.de>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: alan.cox@intel.com, Christoph Hellwig <hch@lst.de>,
Stefano Stabellini <sstabellini@kernel.org>,
ashok.raj@intel.com, Jonathan Corbet <corbet@lwn.net>,
pengfei.xu@intel.com, Ingo Molnar <mingo@redhat.com>,
David Woodhouse <dwmw2@infradead.org>,
kevin.tian@intel.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Steven Rostedt <rostedt@goodmis.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
mika.westerberg@linux.intel.com, Juergen Gross <jgross@suse.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
jacob.jun.pan@intel.com, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v5 02/10] iommu/vt-d: Use per-device dma_ops
Date: Wed, 13 Nov 2019 08:03:12 +0100 [thread overview]
Message-ID: <20191113070312.GA2735@lst.de> (raw)
In-Reply-To: <0885617e-8390-6d18-987f-40d49f9f563e@linux.intel.com>
On Wed, Nov 13, 2019 at 10:50:27AM +0800, Lu Baolu wrote:
> Currently, this is a block issue for using per-device dma ops in Intel
> IOMMU driver. Hence block this driver from using the generic iommu dma
> ops.
That is in fact the reason why I bring it up :)
> I'd like to align Intel IOMMU driver with other vendors. Use iommu dma
> ops for devices which have been selected to go through iommu. And use
> direct dma ops if selected to by pass.
>
> One concern of this propose is that for devices with limited address
> capability, shall we force it to use iommu or alternatively use swiotlb
> if user decides to let it by pass iommu.
>
> I understand that using swiotlb will cause some overhead due to the
> bounced buffer, but Intel IOMMU is default on hence any users who use a
> default kernel won't suffer this. We only need to document this so that
> users understand this overhead when they decide to let such devices by
> pass iommu. This is common to all vendor iommu drivers as far as I can
> see.
Indeed. And one idea would be to lift the code in the powerpc
dma_iommu_ops that check a flag and use the direct ops to the generic
dma code and a flag in struct device. We can then switch the intel
iommu ops (and AMD Gart) over to it.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-11-13 7:03 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 3:17 [PATCH v5 00/10] iommu: Bounce page for untrusted devices Lu Baolu
2019-07-25 3:17 ` [PATCH v5 01/10] iommu/vt-d: Don't switch off swiotlb if use direct dma Lu Baolu
2019-07-25 5:41 ` Christoph Hellwig
2019-07-25 3:17 ` [PATCH v5 02/10] iommu/vt-d: Use per-device dma_ops Lu Baolu
2019-07-25 5:44 ` Christoph Hellwig
2019-07-25 7:18 ` Lu Baolu
2019-07-25 11:43 ` Christoph Hellwig
2019-07-26 1:56 ` Lu Baolu
2019-11-12 7:16 ` Christoph Hellwig
2019-11-13 2:50 ` Lu Baolu
2019-11-13 7:03 ` Christoph Hellwig [this message]
2019-11-13 9:53 ` Christoph Hellwig
2019-11-14 5:14 ` Lu Baolu
2019-11-14 8:14 ` Christoph Hellwig
2019-07-25 3:17 ` [PATCH v5 03/10] iommu/vt-d: Cleanup after use per-device dma ops Lu Baolu
2019-07-25 3:17 ` [PATCH v5 04/10] PCI: Add dev_is_untrusted helper Lu Baolu
2019-07-25 5:44 ` Christoph Hellwig
2019-07-25 3:17 ` [PATCH v5 05/10] swiotlb: Split size parameter to map/unmap APIs Lu Baolu
2019-07-25 11:47 ` Christoph Hellwig
2019-07-25 3:17 ` [PATCH v5 06/10] swiotlb: Zero out bounce buffer for untrusted device Lu Baolu
2019-07-25 11:49 ` Christoph Hellwig
2019-07-26 2:21 ` Lu Baolu
2019-07-25 3:17 ` [PATCH v5 07/10] iommu: Add bounce page APIs Lu Baolu
2019-07-25 3:17 ` [PATCH v5 08/10] iommu/vt-d: Check whether device requires bounce buffer Lu Baolu
2019-07-25 3:17 ` [PATCH v5 09/10] iommu/vt-d: Add trace events for device dma map/unmap Lu Baolu
2019-07-25 12:26 ` Steven Rostedt
2019-07-26 2:24 ` Lu Baolu
2019-07-25 3:17 ` [PATCH v5 10/10] iommu/vt-d: Use bounce buffer for untrusted devices Lu Baolu
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=20191113070312.GA2735@lst.de \
--to=hch@lst.de \
--cc=alan.cox@intel.com \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=boris.ostrovsky@oracle.com \
--cc=corbet@lwn.net \
--cc=dwmw2@infradead.org \
--cc=gregkh@linuxfoundation.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=jgross@suse.com \
--cc=kevin.tian@intel.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mika.westerberg@linux.intel.com \
--cc=mingo@redhat.com \
--cc=pengfei.xu@intel.com \
--cc=robin.murphy@arm.com \
--cc=rostedt@goodmis.org \
--cc=sstabellini@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).