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Date:   Thu, 17 Jan 2019 16:32:06 +0100
From:   Vincent Whitchurch <vincent.whitchurch@axis.com>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Arnd Bergmann <arnd@arndb.de>, sudeep.dutt@intel.com,
        ashutosh.dixit@intel.com, gregkh <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        linux-pci <linux-pci@vger.kernel.org>,
        linux-ntb@googlegroups.com, Jon Mason <jdmason@kudzu.us>,
        Dave Jiang <dave.jiang@intel.com>,
        Allen Hubbe <allenbh@gmail.com>
Subject: Re: [PATCH 0/8] Virtio-over-PCIe on non-MIC
Message-ID: <20190117153206.2flxqb26tbdrwp4z@axis.com>
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On Thu, Jan 17, 2019 at 07:21:42AM -0800, Christoph Hellwig wrote:
> On Thu, Jan 17, 2019 at 04:19:06PM +0100, Vincent Whitchurch wrote:
> > On the RC, a vop-host-backend driver (PCI driver) sets up some shared
> > memory area which the RC and the endpoint can use to communicate the
> > location of the MIC device descriptors and other information such as the
> > MSI address.  It implements vop callbacks to allow the vop framework to
> > obtain the address of the MIC descriptors and send/receive interrupts
> > to/from the guest.
> 
> Why would we require any work on the RC / host side?  A properly
> setup software controlled virtio device should just show up as a
> normal PCIe device, and the virtio-pci device should bind to it.

If I understand you correctly, I think you're talking about the RC
running the virtio drivers and the endpoint implementing the virtio
device?  This vop stuff is used for the other way around: the virtio
device is implement on the RC and the endpoint runs the virtio drivers.