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Date:   Thu, 9 May 2019 10:12:55 +0100
From:   Stefan Hajnoczi <stefanha@gmail.com>
To:     Maxim Levitsky <mlevitsk@redhat.com>
Cc:     Christoph Hellwig <hch@lst.de>, Fam Zheng <fam@euphon.net>,
        Keith Busch <keith.busch@intel.com>,
        Sagi Grimberg <sagi@grimberg.me>, kvm@vger.kernel.org,
        Wolfram Sang <wsa@the-dreams.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Liang Cunming <cunming.liang@intel.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        "David S . Miller" <davem@davemloft.net>,
        Jens Axboe <axboe@fb.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Liu Changpeng <changpeng.liu@intel.com>,
        "Paul E . McKenney" <paulmck@linux.ibm.com>,
        Amnon Ilan <ailan@redhat.com>, John Ferlan <jferlan@redhat.com>
Subject: Re: [PATCH v2 00/10] RFC: NVME MDEV
Message-ID: <20190509091255.GB15331@stefanha-x1.localdomain>
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On Mon, May 06, 2019 at 12:04:06PM +0300, Maxim Levitsky wrote:
> On top of that, it is expected that newer hardware will support the PASID based
> device subdivision, which will allow us to _directly_ pass through the
> submission queues of the device and _force_ us to use the NVME protocol for the
> frontend.

I don't understand the PASID argument.  The data path will be 100%
passthrough and this driver won't be necessary.

In the meantime there is already SPDK for users who want polling.  This
driver's main feature is that the host can still access the device at
the same time as VMs, but I'm not sure that's useful in
performance-critical use cases and for non-performance use cases this
driver isn't necessary.

Stefan

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