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Date:   Wed, 9 Jun 2021 12:01:49 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     "Tian, Kevin" <kevin.tian@intel.com>
Cc:     Jason Gunthorpe <jgg@nvidia.com>,
        "Alex Williamson (alex.williamson@redhat.com)" 
        <alex.williamson@redhat.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
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        Jason Wang <jasowang@redhat.com>,
        "parav@mellanox.com" <parav@mellanox.com>,
        "Enrico Weigelt, metux IT consult" <lkml@metux.net>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Shenming Lu <lushenming@huawei.com>,
        Eric Auger <eric.auger@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        "Raj, Ashok" <ashok.raj@intel.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>, "Wu, Hao" <hao.wu@intel.com>,
        "Jiang, Dave" <dave.jiang@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Robin Murphy <robin.murphy@arm.com>,
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        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Joerg Roedel <joro@8bytes.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: Plan for /dev/ioasid RFC v2
Message-ID: <YMCDfWLw6r80Wdu3@unreal>
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On Mon, Jun 07, 2021 at 02:58:18AM +0000, Tian, Kevin wrote:
> Hi, all,

<...>

> (Remaining opens in v1)

<...>

> -   Device-centric (Jason) vs. group-centric (David) uAPI. David is not fully
>     convinced yet. Based on discussion v2 will continue to have ioasid uAPI
>     being device-centric (but it's fine for vfio to be group-centric). A new
>     section will be added to elaborate this part;

<...>

> (Adopted suggestions)

<...>

> -   (Jason) Addition of device label allows per-device capability/format 
>     check before IOASIDs are created. This leads to another major uAPI 
>     change in v2 - specify format info when creating an IOASID (mapping 
>     protocol, nesting, coherent, etc.). User is expected to check per-device 
>     format and then set proper format for IOASID upon to-be-attached 
>     device;

Sorry for my naive question, I still didn't read all v1 thread and maybe
the answer is already written, but will ask anyway.

Doesn't this adopted suggestion to allow device-specific configuration
actually means that uAPI should be device-centric?

User already needs to be aware of device, configure it explicitly, maybe
gracefully clean it later, it looks like not so much left to be group-centric.

Thanks