public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Barry Song <21cnbao@gmail.com>,
	iommu@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	Christoph Hellwig <hch@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Raj Ashok <ashok.raj@intel.com>,
	"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	mike.campin@intel.com, Yi Liu <yi.l.liu@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	jacob.jun.pan@linux.intel.com
Subject: Re: [RFC 0/7] Support in-kernel DMA with PASID and SVA
Date: Thu, 7 Oct 2021 11:08:58 -0700	[thread overview]
Message-ID: <20211007110858.03cfea88@jacob-builder> (raw)
In-Reply-To: <20211007174822.GK2744544@nvidia.com>

Hi Jason,

On Thu, 7 Oct 2021 14:48:22 -0300, Jason Gunthorpe <jgg@nvidia.com> wrote:

> On Thu, Oct 07, 2021 at 10:50:10AM -0700, Jacob Pan wrote:
> 
> > On platforms that are DMA snooped, this barrier is not needed. But I
> > think your point is that once we convert to DMA API, the sync/barrier
> > is covered by DMA APIs if !dev_is_dma_coherent(dev). Then all archs are
> > good.  
> 
> No.. my point is that a CPU store release is not necessary a DMA
> visiable event on all platforms and things like dma_wmb/rmb() may
> still be necessary. This all needs to be architected before anyone
> starts writing drivers that assume a coherent DMA model without using
> a coherent DMA allocation.
> 
Why is that specific to SVA? Or you are talking about things in general?

Can we ensure coherency at the API level where SVA bind device is
happening? i.e. fail the bind if not passing coherency check.

Thanks,

Jacob

  reply	other threads:[~2021-10-07 18:05 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21 20:29 [RFC 0/7] Support in-kernel DMA with PASID and SVA Jacob Pan
2021-09-21 20:29 ` [RFC 1/7] ioasid: reserve special PASID for in-kernel DMA Jacob Pan
2021-09-21 20:29 ` [RFC 2/7] dma-iommu: Add API for DMA request with PASID Jacob Pan
2021-09-21 20:29 ` [RFC 3/7] iommu/vt-d: Add DMA w/ PASID support for PA and IOVA Jacob Pan
2021-09-21 20:29 ` [RFC 4/7] dma-iommu: Add support for DMA w/ PASID in KVA Jacob Pan
2021-09-21 20:29 ` [RFC 5/7] iommu/vt-d: Add support for KVA PASID mode Jacob Pan
2021-09-21 20:29 ` [RFC 6/7] iommu: Add KVA map API Jacob Pan
2021-09-21 20:29 ` [RFC 7/7] dma/idxd: Use dma-iommu PASID API instead of SVA lib Jacob Pan
2021-09-22 17:04 ` [RFC 0/7] Support in-kernel DMA with PASID and SVA Jason Gunthorpe
2021-09-29 19:37 ` Jacob Pan
2021-09-29 19:39   ` Jason Gunthorpe
2021-09-29 22:57     ` Jacob Pan
2021-09-29 23:43       ` Jason Gunthorpe
2021-09-30 14:22         ` Campin, Mike
2021-09-30 15:21           ` Jacob Pan
2021-10-01 12:24 ` Barry Song
2021-10-01 12:36   ` Jason Gunthorpe
2021-10-01 12:45     ` Barry Song
2021-10-04 16:40       ` Jacob Pan
2021-10-04 18:21         ` Jason Gunthorpe
2021-10-07  5:43           ` Barry Song
2021-10-07 11:32             ` Jason Gunthorpe
2021-10-07 11:54               ` Barry Song
2021-10-07 11:59                 ` Jason Gunthorpe
2021-10-07 17:50                   ` Jacob Pan
2021-10-07 17:48                     ` Jason Gunthorpe
2021-10-07 18:08                       ` Jacob Pan [this message]
2021-10-07 19:11             ` Jacob Pan
2021-10-07 19:10               ` Jason Gunthorpe

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=20211007110858.03cfea88@jacob-builder \
    --to=jacob.jun.pan@linux.intel.com \
    --cc=21cnbao@gmail.com \
    --cc=ashok.raj@intel.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=dave.jiang@intel.com \
    --cc=hch@infradead.org \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jgg@nvidia.com \
    --cc=joro@8bytes.org \
    --cc=kevin.tian@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mike.campin@intel.com \
    --cc=sanjay.k.kumar@intel.com \
    --cc=tony.luck@intel.com \
    --cc=yi.l.liu@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