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Date: Fri, 04 May 2012 08:19:13 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [RFC 0/9] Virtio-mmio refactoring.
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: aliguori@us.ibm.com, i.mitsyanko@samsung.com, Evgeny Voevodin <e.voevodin@samsung.com>, qemu-devel@nongnu.org, kyungmin.park@samsung.com, d.solodkiy@samsung.com, m.kozlov@samsung.com

On 05/03/2012 07:14 AM, Peter Maydell wrote:
> On 25 April 2012 06:54, Evgeny Voevodin<e.voevodin@samsung.com>  wrote:
>> In this patchset refactoring of virtio-mmio layer is made.
>> Instead of creating virtio-blk-mmio, virtio-net-mmio, etc on the system bus
>> we create virtio-blk, virtio-net, etc devices on the virtio-transport bus.
>> To create virtio-transport bus virtio-mmio-transport device provided.
>> Transport device plugs into virtio-mmio bus.
>> To create virtio-mmio bus virtio-mmio-bridge device provided.
>
> This seems to me to have one more layer than it needs. Why not just:
>   create virtio-blk, virtio-net, etc on the virtio-transport bus
>   To create virtio-transport bus, we create a virtio-mmio-transport
>   device, and this device is a sysbus device.
>
> ie why do you have separate "virtio-mmio-transport" and
> "virtio-mmio-bridge" devices, and two different new buses ("virtio-mmio"
> and "virtio-transport") rather than just "virtio-transport"?

I think using a bus won't work.   You need to create a VirtioDevice that has a 
link<VirtioTransport>.  I would suggest making VirtioTransport an interface.

Then you can have VirtioPCI inherit from PCIDevice and implement VirtioTransport.

Regards,

Anthony Liguori

>
> -- PMM
>