From: Jason Gunthorpe <jgg@nvidia.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: iommu@lists.linux-foundation.org,
LKML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Christoph Hellwig <hch@infradead.org>,
"Tian, Kevin" <kevin.tian@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
mike.campin@intel.com, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC 0/7] Support in-kernel DMA with PASID and SVA
Date: Wed, 29 Sep 2021 16:39:53 -0300 [thread overview]
Message-ID: <20210929193953.GX964074@nvidia.com> (raw)
In-Reply-To: <20210929123437.721991dc@jacob-builder>
On Wed, Sep 29, 2021 at 12:37:19PM -0700, Jacob Pan wrote:
> For #2, it seems we can store the kernel PASID in struct device. This will
> preserve the DMA API interface while making it PASID capable. Essentially,
> each PASID capable device would have two special global PASIDs:
> - PASID 0 for DMA request w/o PASID, aka RID2PASID
> - PASID 1 (randomly selected) for in-kernel DMA request w/ PASID
This seems reasonable, I had the same thought. Basically just have the
driver issue some trivial call:
pci_enable_pasid_dma(pdev, &pasid)
And then DMA tagged with the PASID will be handled equivilant to
untagged DMA. Basically PASID and no PASID point to the exact same IO
page table and the DMA API manipulates that single page table.
Having multiple RID's pointing at the same IO page table is something
we expect iommufd to require so the whole thing should ideally fall
out naturally.
Jason
next prev parent reply other threads:[~2021-09-29 19:39 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 [this message]
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
2021-10-07 19:11 ` Jacob Pan
2021-10-07 19:10 ` Jason Gunthorpe
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