From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
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, Alan Cox <alan@linux.intel.com>,
Juergen Gross <jgross@suse.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mika Westerberg <mika.westerberg@intel.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
jacob.jun.pan@intel.com, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v6 5/8] iommu: Add bounce page APIs
Date: Fri, 16 Aug 2019 10:45:13 +0800 [thread overview]
Message-ID: <ec1dc4e2-626c-9c12-f17c-b51420fc2e81@linux.intel.com> (raw)
In-Reply-To: <20190815154845.GA18327@8bytes.org>
Hi Joerg,
On 8/15/19 11:48 PM, Joerg Roedel wrote:
> On Thu, Aug 15, 2019 at 02:15:32PM +0800, Lu Baolu wrote:
>> iommu_map/unmap() APIs haven't parameters for dma direction and
>> attributions. These parameters are elementary for DMA APIs. Say,
>> after map, if the dma direction is TO_DEVICE and a bounce buffer is
>> used, we must sync the data from the original dma buffer to the bounce
>> buffer; In the opposite direction, if dma is FROM_DEVICE, before unmap,
>> we need to sync the data from the bounce buffer onto the original
>> buffer.
>
> The DMA direction from DMA-API maps to the protections in iommu_map():
>
> DMA_FROM_DEVICE: IOMMU_WRITE
> DMA_TO_DEVICE: IOMMU_READ
> DMA_BIDIRECTIONAL IOMMU_READ | IOMMU_WRITE
>
> And for the sync DMA-API also has separate functions for either
> direction. So I don't see why these extra functions are needed in the
> IOMMU-API.
>
Okay. I understand that adding these APIs in iommu.c is not a good idea.
And, I also don't think merging the bounce buffer implementation into
iommu_map() is feasible since iommu_map() is not DMA API centric.
The bounce buffer implementation will eventually be part of DMA APIs
defined in dma-iommu.c, but currently those APIs are not ready for x86
use yet. So I will put them in iommu/vt-d driver for this time being and
will move them to dma-iommu.c later.
Does this work for you?
Best regards,
Lu Baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-08-16 2:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 4:52 [PATCH v6 0/8] iommu: Bounce page for untrusted devices Lu Baolu
2019-07-30 4:52 ` [PATCH v6 1/8] iommu/vt-d: Don't switch off swiotlb if use direct dma Lu Baolu
2019-07-30 4:52 ` [PATCH v6 2/8] PCI: Add dev_is_untrusted helper Lu Baolu
2019-07-30 4:52 ` [PATCH v6 3/8] swiotlb: Split size parameter to map/unmap APIs Lu Baolu
2019-07-30 4:52 ` [PATCH v6 4/8] swiotlb: Zero out bounce buffer for untrusted device Lu Baolu
2019-07-30 4:52 ` [PATCH v6 5/8] iommu: Add bounce page APIs Lu Baolu
2019-08-14 8:38 ` Joerg Roedel
2019-08-15 6:15 ` Lu Baolu
2019-08-15 15:48 ` Joerg Roedel
2019-08-16 2:45 ` Lu Baolu [this message]
2019-08-16 4:46 ` Christoph Hellwig
2019-08-18 3:07 ` Lu Baolu
2019-07-30 4:52 ` [PATCH v6 6/8] iommu/vt-d: Check whether device requires bounce buffer Lu Baolu
2019-07-30 4:52 ` [PATCH v6 7/8] iommu/vt-d: Add trace events for device dma map/unmap Lu Baolu
2019-07-30 4:52 ` [PATCH v6 8/8] 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=ec1dc4e2-626c-9c12-f17c-b51420fc2e81@linux.intel.com \
--to=baolu.lu@linux.intel.com \
--cc=alan.cox@intel.com \
--cc=alan@linux.intel.com \
--cc=ashok.raj@intel.com \
--cc=bhelgaas@google.com \
--cc=boris.ostrovsky@oracle.com \
--cc=corbet@lwn.net \
--cc=dwmw2@infradead.org \
--cc=gregkh@linuxfoundation.org \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=jgross@suse.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mika.westerberg@intel.com \
--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).