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From:   "Tian, Kevin" <kevin.tian@intel.com>
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        "iommu@lists.linux-foundation.org" <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>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>
CC:     "Pan, Jacob jun" <jacob.jun.pan@intel.com>,
        "Raj, Ashok" <ashok.raj@intel.com>,
        "Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
        "Jiang, Dave" <dave.jiang@intel.com>,
        "Luck, Tony" <tony.luck@intel.com>,
        "Zanussi, Tom" <tom.zanussi@intel.com>,
        "Williams, Dan J" <dan.j.williams@intel.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>
Subject: RE: [PATCH v2 0/8] Enable PASID for DMA API users
Thread-Topic: [PATCH v2 0/8] Enable PASID for DMA API users
Thread-Index: AQHYOCoZX1e6IOSYG0mi+cTZStvSnazAGQ3g
Date:   Tue, 15 Mar 2022 08:16:59 +0000
Message-ID: <BN9PR11MB5276F78A62AD159A73868C268C109@BN9PR11MB5276.namprd11.prod.outlook.com>
References: <20220315050713.2000518-1-jacob.jun.pan@linux.intel.com>
In-Reply-To: <20220315050713.2000518-1-jacob.jun.pan@linux.intel.com>
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> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Sent: Tuesday, March 15, 2022 1:07 PM
>=20
> Some modern accelerators such as Intel's Data Streaming Accelerator (DSA)
> require PASID in DMA requests to be operational. Specifically, the work
> submissions with ENQCMD on shared work queues require PASIDs. The use
> cases
> include both user DMA with shared virtual addressing (SVA) and in-kernel
> DMA similar to legacy DMA w/o PASID. Here we address the latter.
>=20
> DMA mapping API is the de facto standard for in-kernel DMA. However, it
> operates on a per device or Requester ID(RID) basis which is not
> PASID-aware. To leverage DMA API for devices relies on PASIDs, this
> patchset introduces the following APIs
>=20
> 1. A driver facing API that enables DMA API PASID usage:
> iommu_enable_pasid_dma(struct device *dev, ioasid_t &pasid);

Should this be called dma_enable_pasid() since it's about DMA API? Doing
so also avoids the driver to include iommu.h.

Thanks
Kevin