From: Jason Gunthorpe <jgg@nvidia.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org, Joerg Roedel <joro@8bytes.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Christoph Hellwig <hch@infradead.org>,
Yi Liu <yi.l.liu@intel.com>, Raj Ashok <ashok.raj@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
wangzhou1@hisilicon.com, zhangfei.gao@linaro.org,
vkoul@kernel.org, David Woodhouse <dwmw2@infradead.org>
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
WARNING: multiple messages have this Message-ID (diff)
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
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-05-11 16:35 UTC|newest]
Thread overview: 58+ 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 ` 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 13:25 ` Jacob Pan
2021-05-10 23:37 ` Jason Gunthorpe
2021-05-10 23:37 ` Jason Gunthorpe
2021-05-11 3:31 ` Jacob Pan
2021-05-11 3:31 ` Jacob Pan
2021-05-11 11:48 ` Jason Gunthorpe
2021-05-11 11:48 ` Jason Gunthorpe
2021-05-11 16:14 ` Jacob Pan
2021-05-11 16:14 ` Jacob Pan
2021-05-11 16:35 ` Jason Gunthorpe [this message]
2021-05-11 16:35 ` Jason Gunthorpe
2021-05-11 18:05 ` Jacob Pan
2021-05-11 18:05 ` Jacob Pan
2021-05-11 19:47 ` Jason Gunthorpe
2021-05-11 19:47 ` Jason Gunthorpe
2021-05-12 6:37 ` Christoph Hellwig
2021-05-12 6:37 ` Christoph Hellwig
2021-05-13 13:00 ` Jacob Pan
2021-05-13 13:00 ` Jacob Pan
2021-05-13 13:38 ` Jason Gunthorpe
2021-05-13 13:38 ` Jason Gunthorpe
2021-05-13 15:10 ` Jacob Pan
2021-05-13 15:10 ` Jacob Pan
2021-05-13 16:44 ` Luck, Tony
2021-05-13 16:44 ` Luck, Tony
2021-05-13 17:33 ` Jason Gunthorpe
2021-05-13 17:33 ` Jason Gunthorpe
2021-05-13 18:53 ` Luck, Tony
2021-05-13 18:53 ` Luck, Tony
2021-05-13 19:00 ` Jason Gunthorpe
2021-05-13 19:00 ` Jason Gunthorpe
2021-05-13 19:14 ` Luck, Tony
2021-05-13 19:14 ` Luck, Tony
2021-05-13 19:20 ` Jason Gunthorpe
2021-05-13 19:20 ` Jason Gunthorpe
2021-05-13 19:46 ` Jacob Pan
2021-05-13 19:46 ` Jacob Pan
2021-05-13 19:57 ` Luck, Tony
2021-05-13 19:57 ` Luck, Tony
2021-05-13 20:22 ` Jacob Pan
2021-05-13 20:22 ` Jacob Pan
2021-05-13 22:31 ` Jason Gunthorpe
2021-05-13 22:31 ` Jason Gunthorpe
2021-05-13 23:40 ` Jacob Pan
2021-05-13 23:40 ` Jacob Pan
2021-05-17 14:37 ` Jason Gunthorpe
2021-05-17 14:37 ` Jason Gunthorpe
2021-05-19 15:46 ` Jacob Pan
2021-05-19 15:46 ` Jacob Pan
2021-05-12 10:18 ` Jean-Philippe Brucker
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
2021-05-10 13:25 ` Jacob Pan
2021-05-12 10:24 ` Jean-Philippe Brucker
2021-05-12 10:24 ` Jean-Philippe Brucker
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