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To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
 Daniil Egranov <daniil.egranov@arm.com>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
 Leif Lindholm <leif.lindholm@linaro.org>
References: <20180307013637.16462-1-daniil.egranov@arm.com>
 <CAKv+Gu9qXzqxLG0-a_hU7pwuW-B1=-y+iDCOmFYKx6kZ=nX3QA@mail.gmail.com>
From: Laszlo Ersek <lersek@redhat.com>
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Date: Wed, 7 Mar 2018 21:18:51 +0100
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Subject: Re: [PATCH 0/4] Virtio non-discoverable devices
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On 03/07/18 09:03, Ard Biesheuvel wrote:
> (+ Laszlo)
> 
> Hello Daniil,
> 
> On 7 March 2018 at 01:36, Daniil Egranov <daniil.egranov@arm.com> wrote:
>> This is an attempt to add MMIO Virtio devices into the
>> non-discoverable device registration procedure and allow
>> Virtio PCI drivers to recognize and program such devices
>> correctly.
> 
> Why? The purpose of the non-discoverable device layer is to make
> non-PCI controllers that can be driven by PCI class drivers appear as
> PCI devices. We have started using the base non-discoverable device
> protocol for other devices as well, but the PCI wrapper is really only
> intended for PCI class drivers.
> 
> For VirtIO MMIO, we already have a driver model driver, and given that
> you need to patch up differences between MMIO and PCI based virtio in
> your code, I am reluctant to incorporate modifications in to the PCI
> driver to support MMIO devices.

I'm impressed and thankful that you managed to say it in two paragraphs
-- I needed ten or more :)

Thanks,
Laszlo