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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 17 Jan 2019 17:34:10 +0100
Message-ID: <CAK8P3a3qoxXZqrAuusw++dAU8csHDLHkPNhojjO0AF3FL3jZBg@mail.gmail.com>
Subject: Re: [PATCH 0/8] Virtio-over-PCIe on non-MIC
To:     Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc:     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>
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On Thu, Jan 17, 2019 at 5:26 PM Vincent Whitchurch
<vincent.whitchurch@axis.com> wrote:
> On Thu, Jan 17, 2019 at 04:53:25PM +0100, Arnd Bergmann wrote:
> > On Thu, Jan 17, 2019 at 4:19 PM Vincent Whitchurch

> > Ok, this seems fine so far. So the vop-host-backend is a regular PCI
> > driver that implements the VOP protocol from the host side, and it
> > can talk to either a MIC, or another guest-backend written for the PCI-EP
> > framework to implement the same protocol, right?
>
> Yes, but just to clarify:  the placement of the device page and the way
> to communicate the location of the device page address and any other
> information needed by the guest-backend are hardware-specific so there
> is no generic vop-host-backend implementation which can talk to both a
> MIC and to something else.

I'm not sure I understand what is hardware specific about it. Shouldn't
it be possible to define at least a vop-host-backend that could work with
any guest-backend running on the PCI-EP framework?

This may have to be different from the interface used on MIC, but
generally speaking that is what I expect from a PCI device.

       Arnd