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From: Jason Gunthorpe <jgg@nvidia.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: vkoul@kernel.org, "Tian, Kevin" <kevin.tian@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Raj Ashok <ashok.raj@intel.com>,
	David Woodhouse <dwmw2@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	iommu@lists.linux-foundation.org, zhangfei.gao@linaro.org,
	Jean-Philippe Brucker <jean-philippe@linaro.com>
Subject: Re: [PATCH v4 1/2] iommu/sva: Tighten SVA bind API with explicit flags
Date: Tue, 11 May 2021 13:35:21 -0300	[thread overview]
Message-ID: <20210511163521.GN1002214@nvidia.com> (raw)
In-Reply-To: <20210511091452.721e9a03@jacob-builder>

On Tue, May 11, 2021 at 09:14:52AM -0700, Jacob Pan wrote:

> > Honestly, I'm not convinced we should have "kernel SVA" at all.. Why
> > does IDXD use normal DMA on the RID for kernel controlled accesses?
> 
> Using SVA simplifies the work submission, there is no need to do map/unmap.
> Just bind PASID with init_mm, then submit work directly either with ENQCMDS
> (supervisor version of ENQCMD) to a shared workqueue or put the supervisor
> PASID in the descriptor for dedicated workqueue.

That is not OK, protable drivers in Linux have to sue dma map/unmap
calls to manage cache coherence. PASID does not opt out of any of
that.

I dislike this whole idea a lot. A single driver should not opt itself
out of IOMMU based security "just because"

Jason
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  reply	other threads:[~2021-05-11 16:35 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 13:25 [PATCH v4 0/2] Simplify and restrict IOMMU SVA APIs Jacob Pan
2021-05-10 13:25 ` [PATCH v4 1/2] iommu/sva: Tighten SVA bind API with explicit flags Jacob Pan
2021-05-10 23:37   ` Jason Gunthorpe
2021-05-11  3:31     ` Jacob Pan
2021-05-11 11:48       ` Jason Gunthorpe
2021-05-11 16:14         ` Jacob Pan
2021-05-11 16:35           ` Jason Gunthorpe [this message]
2021-05-11 18:05             ` Jacob Pan
2021-05-11 19:47               ` Jason Gunthorpe
2021-05-12  6:37                 ` Christoph Hellwig
2021-05-13 13:00                   ` Jacob Pan
2021-05-13 13:38                     ` Jason Gunthorpe
2021-05-13 15:10                       ` Jacob Pan
2021-05-13 16:44                         ` Luck, Tony
2021-05-13 17:33                           ` Jason Gunthorpe
2021-05-13 18:53                             ` Luck, Tony
2021-05-13 19:00                               ` Jason Gunthorpe
2021-05-13 19:14                                 ` Luck, Tony
2021-05-13 19:20                                   ` Jason Gunthorpe
2021-05-13 19:46                                     ` Jacob Pan
2021-05-13 19:57                                       ` Luck, Tony
2021-05-13 20:22                                         ` Jacob Pan
2021-05-13 22:31                                           ` Jason Gunthorpe
2021-05-13 23:40                                             ` Jacob Pan
2021-05-17 14:37                                               ` Jason Gunthorpe
2021-05-19 15:46                                                 ` Jacob Pan
2021-05-12 10:18   ` Jean-Philippe Brucker
2021-05-10 13:25 ` [PATCH v4 2/2] iommu/sva: Remove mm parameter from SVA bind API Jacob Pan
2021-05-12 10:24   ` Jean-Philippe Brucker

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