From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Juan Quintela <quintela@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 0/9] Virtio cleanups
Date: Mon, 22 Mar 2010 13:30:01 +0000 [thread overview]
Message-ID: <201003221330.02217.paul@codesourcery.com> (raw)
In-Reply-To: <4BA6DB3F.7010702@codemonkey.ws>
> A VirtIOBlock device cannot be a VirtIODevice while being a
> VirtIOPCIProxy (proxy is a poor name, btw).
>
> It really ought to be:
>
> DeviceState -> VirtIODevice -> VirtIOBlock
>
> and:
>
> PCIDevice -> VirtIOPCI : implements VirtIOBus
>
> The interface between the VirtIODevice and VirtIOBus is the virtio
> transport.
>
> The main reason a separate bus is needed is the same reason it's needed
> in Linux. VirtIOBlock has to be tied to some bus. It cannot be tied to
> the PCI bus without having it be part of the implementation detail.
> Introducing another bus type fixes this (and it's what we do in the
> kernel).
Why does virtio need a device state and bus at all?
Can't it just be an internal implementation interface, which happens to be
used by all devices that happen to exposed a block device over a virtio
transport?
If you have a virtio bus then IMO the PCI bridge device should be independent
of the virtio device that is connected to it.
Paul
next prev parent reply other threads:[~2010-03-22 13:30 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-16 18:51 [Qemu-devel] [PATCH 0/9] Virtio cleanups Juan Quintela
2010-03-16 18:51 ` [Qemu-devel] [PATCH 1/9] qemu/pci: document msix_entries_nr field Juan Quintela
2010-03-16 18:51 ` [Qemu-devel] [PATCH 2/9] virtio: Teach virtio-balloon about DO_UPCAST Juan Quintela
2010-03-18 7:29 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-16 18:51 ` [Qemu-devel] [PATCH 3/9] virtio: Teach virtio-blk " Juan Quintela
2010-03-18 7:29 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-16 18:51 ` [Qemu-devel] [PATCH 4/9] virtio: Teach virtio-net " Juan Quintela
2010-03-18 7:29 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-16 18:51 ` [Qemu-devel] [PATCH 5/9] virtio: Use DO_UPCAST instead of a cast Juan Quintela
2010-03-18 7:30 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-16 18:51 ` [Qemu-devel] [PATCH 6/9] virtio-pci: Remove duplicate test Juan Quintela
2010-03-18 7:25 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-18 8:26 ` Juan Quintela
2010-03-18 8:47 ` Michael S. Tsirkin
2010-03-18 8:59 ` Juan Quintela
2010-03-18 9:11 ` Michael S. Tsirkin
2010-03-18 11:40 ` Juan Quintela
2010-03-18 13:24 ` Michael S. Tsirkin
2010-03-18 13:47 ` Juan Quintela
2010-03-16 18:51 ` [Qemu-devel] [PATCH 7/9] QLIST: Introduce QLIST_COPY_HEAD Juan Quintela
2010-03-16 18:51 ` [Qemu-devel] [PATCH 8/9] virtio-blk: change rq type to VirtIOBlockReq Juan Quintela
2010-03-18 7:27 ` [Qemu-devel] " Michael S. Tsirkin
2010-03-16 18:51 ` [Qemu-devel] [PATCH 9/9] virtio-blk: use QLIST for the list of requests Juan Quintela
2010-03-18 6:40 ` [Qemu-devel] Re: [PATCH 0/9] Virtio cleanups Michael S. Tsirkin
2010-03-18 7:36 ` Juan Quintela
2010-03-18 7:42 ` Michael S. Tsirkin
2010-03-18 8:36 ` Juan Quintela
2010-03-18 9:07 ` Michael S. Tsirkin
2010-03-18 11:53 ` Juan Quintela
2010-03-18 12:33 ` Michael S. Tsirkin
2010-03-18 13:43 ` Juan Quintela
2010-03-18 13:47 ` Michael S. Tsirkin
2010-03-18 14:21 ` Juan Quintela
2010-03-18 17:13 ` Michael S. Tsirkin
2010-03-19 1:41 ` Jamie Lokier
2010-03-21 14:31 ` Michael S. Tsirkin
2010-03-21 18:11 ` Jamie Lokier
2010-03-21 19:16 ` Michael S. Tsirkin
2010-03-22 1:06 ` Juan Quintela
2010-03-22 2:51 ` Anthony Liguori
2010-03-22 13:30 ` Paul Brook [this message]
2010-03-22 14:49 ` Anthony Liguori
2010-03-22 14:50 ` Michael S. Tsirkin
2010-03-22 15:03 ` Anthony Liguori
2010-03-22 15:17 ` Michael S. Tsirkin
2010-03-22 15:50 ` Anthony Liguori
2010-03-22 16:16 ` Paul Brook
2010-03-22 18:48 ` Anthony Liguori
2010-03-22 21:00 ` Paul Brook
2010-03-23 1:13 ` Anthony Liguori
2010-03-22 15:51 ` Paul Brook
2010-03-22 17:19 ` Michael S. Tsirkin
2010-03-22 22:16 ` Juan Quintela
2010-03-23 0:49 ` Paul Brook
2010-03-23 1:16 ` Anthony Liguori
2010-03-23 10:47 ` Michael S. Tsirkin
2010-03-23 11:11 ` Gerd Hoffmann
2010-03-23 11:40 ` Paul Brook
2010-03-23 11:58 ` Michael S. Tsirkin
2010-03-23 12:32 ` Juan Quintela
2010-03-21 19:57 ` Michael S. Tsirkin
2010-03-22 1:13 ` Juan Quintela
2010-03-22 8:37 ` Michael S. Tsirkin
2010-03-18 10:05 ` Michael S. Tsirkin
2010-03-18 15:43 ` Gerd Hoffmann
2010-03-18 16:20 ` Juan Quintela
2010-03-18 16:36 ` Gerd Hoffmann
2010-03-18 17:08 ` Juan Quintela
2010-03-18 17:21 ` Michael S. Tsirkin
2010-03-18 19:37 ` Juan Quintela
2010-03-18 20:07 ` Anthony Liguori
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