From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: <iommu@lists.linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joro@8bytes.org>, Jason Gunthorpe <jgg@nvidia.com>,
"Christoph Hellwig" <hch@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Jacob Pan <jacob.jun.pan@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>, Yi Liu <yi.l.liu@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
Barry Song <21cnbao@gmail.com>,
"Zanussi, Tom" <tom.zanussi@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH 2/4] iommu: Add PASID support for DMA mapping API users
Date: Wed, 8 Dec 2021 10:49:39 -0800 [thread overview]
Message-ID: <20211208104939.732fa5b9@jacob-builder> (raw)
In-Reply-To: <16408193-c8bc-3046-b32f-9274bf0b415c@linux.intel.com>
Hi Lu,
On Wed, 8 Dec 2021 10:31:36 +0800, Lu Baolu <baolu.lu@linux.intel.com>
wrote:
> Hi Jacob,
>
> On 12/7/21 9:47 PM, Jacob Pan wrote:
> > DMA mapping API is the de facto standard for in-kernel DMA. It operates
> > on a per device/RID basis which is not PASID-aware.
> >
> > Some modern devices such as Intel Data Streaming Accelerator, PASID is
> > required for certain work submissions. To allow such devices use DMA
> > mapping API, we need the following functionalities:
> > 1. Provide device a way to retrieve a kernel PASID for work submission
> > 2. Enable the kernel PASID on the IOMMU
> > 3. Establish address space for the kernel PASID that matches the default
> > domain. Let it be IOVA or physical address in case of pass-through.
> >
> > This patch introduces a driver facing API that enables DMA API
> > PASID usage. Once enabled, device drivers can continue to use DMA APIs
> > as is. There is no difference in dma_handle between without PASID and
> > with PASID.
>
> Can a device issue DMA requests with PASID even there's no system IOMMU
> or the system IOMMU is disabled?
>
Good point.
If IOMMU is not enabled, device cannot issue DMA requests with PASID. This
API will not be available. Forgot to add dummy functions to the header.
> Best regards,
> baolu
Thanks,
Jacob
next prev parent reply other threads:[~2021-12-08 18:45 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 13:47 [PATCH 0/4] Enable PASID for DMA API users Jacob Pan
2021-12-07 13:47 ` [PATCH 1/4] ioasid: Reserve a global PASID for in-kernel DMA Jacob Pan
2021-12-09 11:03 ` Jean-Philippe Brucker
2021-12-09 18:14 ` Jacob Pan
2021-12-10 9:06 ` Jean-Philippe Brucker
2021-12-10 12:31 ` Jason Gunthorpe
2021-12-10 18:05 ` Jacob Pan
2021-12-11 8:39 ` Tian, Kevin
2021-12-12 23:34 ` Jason Gunthorpe
2021-12-07 13:47 ` [PATCH 2/4] iommu: Add PASID support for DMA mapping API users Jacob Pan
2021-12-08 2:31 ` Lu Baolu
2021-12-08 18:49 ` Jacob Pan [this message]
2021-12-09 1:56 ` Tian, Kevin
2021-12-09 2:21 ` Lu Baolu
2021-12-09 16:32 ` Jacob Pan
2021-12-09 16:57 ` Raj, Ashok
2021-12-09 17:34 ` Jacob Pan
2021-12-07 13:47 ` [PATCH 3/4] iommu/vt-d: Support PASID DMA for in-kernel usage Jacob Pan
2021-12-08 13:22 ` Jason Gunthorpe
2021-12-08 19:16 ` Jacob Pan
2021-12-09 2:32 ` Lu Baolu
2021-12-09 23:21 ` Jacob Pan
2021-12-09 23:41 ` Jason Gunthorpe
2021-12-10 6:46 ` Lu Baolu
2021-12-10 17:50 ` Jacob Pan
2021-12-10 17:48 ` Jason Gunthorpe
2021-12-10 18:18 ` Jacob Pan
2021-12-10 18:53 ` Jason Gunthorpe
2021-12-07 13:47 ` [PATCH 4/4] dmaengine: idxd: Use DMA API for in-kernel DMA with PASID Jacob Pan
2021-12-07 23:27 ` Dave Jiang
2021-12-08 4:56 ` Vinod Koul
2021-12-08 17:36 ` Jacob Pan
2021-12-08 13:13 ` Jason Gunthorpe
2021-12-08 15:35 ` Dave Jiang
2021-12-08 17:51 ` Jason Gunthorpe
2021-12-09 1:48 ` Tian, Kevin
2021-12-09 19:18 ` Jacob Pan
2021-12-08 19:55 ` Jacob Pan
2021-12-08 20:30 ` Jason Gunthorpe
2021-12-08 21:59 ` Jacob Pan
2021-12-08 23:39 ` Jason Gunthorpe
2021-12-09 0:12 ` Dave Jiang
2021-12-09 2:06 ` Tian, Kevin
2021-12-08 18:37 ` kernel test robot
2021-12-08 13:10 ` [PATCH 0/4] Enable PASID for DMA API users Jason Gunthorpe
2021-12-08 18:15 ` Jacob Pan
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