From: Jason Gunthorpe <jgg@nvidia.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>,
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>,
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>,
"Luck, Tony" <tony.luck@intel.com>
Subject: Re: [PATCH v4 1/2] iommu/sva: Tighten SVA bind API with explicit flags
Date: Thu, 13 May 2021 10:38:34 -0300 [thread overview]
Message-ID: <20210513133834.GC1002214@nvidia.com> (raw)
In-Reply-To: <20210513060012.0fcc7653@jacob-builder>
On Thu, May 13, 2021 at 06:00:12AM -0700, Jacob Pan wrote:
> > > If you want to do SVA PASID then it also must come with DMA APIs to
> > > manage the CPU cache coherence that are all NOP's on x86.
> >
> > Yes. And we have plenty of precende where an IOMMU is in "bypass" mode
> > to allow access to all memory and then uses the simple dma-direct case.
> I agree it is better not to expose the entire direct map. But the missing
> piece of using DMA APIs is the PASID. The caller needs the PASID value to
> do work submission once buffer is mapped.
You still haven't explained why the kernel driver should have a PASID at all.
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, "Luck,
Tony" <tony.luck@intel.com>,
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: Thu, 13 May 2021 10:38:34 -0300 [thread overview]
Message-ID: <20210513133834.GC1002214@nvidia.com> (raw)
In-Reply-To: <20210513060012.0fcc7653@jacob-builder>
On Thu, May 13, 2021 at 06:00:12AM -0700, Jacob Pan wrote:
> > > If you want to do SVA PASID then it also must come with DMA APIs to
> > > manage the CPU cache coherence that are all NOP's on x86.
> >
> > Yes. And we have plenty of precende where an IOMMU is in "bypass" mode
> > to allow access to all memory and then uses the simple dma-direct case.
> I agree it is better not to expose the entire direct map. But the missing
> piece of using DMA APIs is the PASID. The caller needs the PASID value to
> do work submission once buffer is mapped.
You still haven't explained why the kernel driver should have a PASID at all.
Jason
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iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-05-13 13:38 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
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 [this message]
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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