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From: Paul Brook <paul@codesourcery.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: "chrisw@redhat.com" <chrisw@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	"avi@redhat.com" <avi@redhat.com>,
	"kraxel@redhat.com" <kraxel@redhat.com>
Subject: Re: [Qemu-devel] [RFC PATCH 1/5] qdev: Create qdev_get_dev_path()
Date: Tue, 15 Jun 2010 14:32:38 +0100	[thread overview]
Message-ID: <201006151432.38864.paul@codesourcery.com> (raw)
In-Reply-To: <201006151419.54215.paul@codesourcery.com>

> > > Every hotplug-capable bus must have a proper addressing scheme, I think
> > > this is a reasonable and achievable requirement. Then we don't need
> > > instance numbers for those buses.
> > 
> > What about USB?
> 
> USB has useful device addresses (physical ports).
> These aren't used by most of the higher-level protocols (logically USB is a
> flat bus structure), but the physically tree topology is still there if you
> look hard enough.

... and thinking about it a bit more, this adds an extra addressing 
possibility. 

USB devices have both physical and logical.  The physical addresses is which 
port the device is plugged into (including port addresses of any intermediate 
hubs). These never change, so should be the canonical address.

The logical address is set by the guest OS so may change (or be absent). Most 
software uses the logical address, so this is by far the most useful option 
for mapping from a guest device to a qemu device.

Paul

  reply	other threads:[~2010-06-15 13:34 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-14  5:51 [Qemu-devel] [RFC PATCH 0/5] Introduce canonical device hierarchy string Alex Williamson
2010-06-14  5:51 ` [Qemu-devel] [RFC PATCH 1/5] qdev: Create qdev_get_dev_path() Alex Williamson
2010-06-14  6:39   ` Markus Armbruster
2010-06-14 12:52     ` Alex Williamson
2010-06-14 13:00       ` Jan Kiszka
2010-06-14 13:09       ` Paul Brook
2010-06-14 15:29         ` Alex Williamson
2010-06-14 15:42           ` Paul Brook
2010-06-14 16:00           ` Jan Kiszka
2010-06-14 16:38             ` Alex Williamson
2010-06-14 16:49               ` Jan Kiszka
2010-06-14 18:35                 ` Alex Williamson
2010-06-14 21:43                   ` Paul Brook
2010-06-14 22:11                     ` Alex Williamson
2010-06-14 22:46                       ` Paul Brook
2010-06-15  1:14                         ` Alex Williamson
2010-06-15 11:24                           ` Paul Brook
2010-06-15  8:47         ` Markus Armbruster
2010-06-15  9:34           ` Jan Kiszka
2010-06-15 11:28             ` Paul Brook
2010-06-15 11:45               ` Jan Kiszka
2010-06-15 12:04                 ` Paul Brook
2010-06-15 12:16                   ` Jan Kiszka
2010-06-15 12:39                     ` Paul Brook
2010-06-15 13:00                       ` Jan Kiszka
2010-06-15 13:14                         ` Paul Brook
2010-06-15 13:16                 ` Markus Armbruster
2010-06-15 13:32                   ` Jan Kiszka
2010-06-15 20:53               ` Alex Williamson
2010-06-15 21:55                 ` Paul Brook
2010-06-15 22:33                   ` Alex Williamson
2010-06-15 23:01                     ` Paul Brook
2010-06-15 23:10                       ` Alex Williamson
2010-06-16  0:25                       ` Chris Wright
2010-06-16  0:30                         ` Paul Brook
2010-06-16  0:35                           ` Chris Wright
2010-06-16  1:30                             ` Paul Brook
2010-06-16  2:55                               ` Alex Williamson
2010-06-16  8:23                 ` Markus Armbruster
2010-06-17 22:25                   ` Alex Williamson
2010-06-18  9:16                     ` Jan Kiszka
2010-06-18 15:01                       ` Alex Williamson
2010-06-18 15:22                         ` Jan Kiszka
2010-06-18 14:03                     ` Markus Armbruster
2010-06-18 14:14                       ` Jan Kiszka
2010-06-18 15:21                       ` Alex Williamson
2010-06-15 11:42             ` Markus Armbruster
2010-06-15 11:59               ` Jan Kiszka
2010-06-15 13:07                 ` Markus Armbruster
2010-06-15 13:19                   ` Paul Brook
2010-06-15 13:32                     ` Paul Brook [this message]
2010-06-15 15:08                   ` Jan Kiszka
2010-06-16 13:02                     ` Markus Armbruster
2010-06-14  5:51 ` [Qemu-devel] [RFC PATCH 2/5] savevm: Add DeviceState param Alex Williamson
2010-06-14  5:51 ` [Qemu-devel] [RFC PATCH 3/5] savevm: Make use of the new " Alex Williamson
2010-06-14  5:51 ` [Qemu-devel] [RFC PATCH 4/5] eepro100: Add a dev field to eeprom new/free functions Alex Williamson
2010-06-14  5:51 ` [Qemu-devel] [RFC PATCH 5/5] virtio-net: Incorporate a DeviceState pointer and let savevm track instances Alex Williamson
2010-06-14  7:02 ` [Qemu-devel] Re: [RFC PATCH 0/5] Introduce canonical device hierarchy string Gerd Hoffmann
2010-06-14 19:56   ` Alex Williamson
2010-06-15  8:53     ` Markus Armbruster
2010-06-15 18:01       ` Alex Williamson
2010-06-16  8:34         ` Markus Armbruster
2010-06-16  8:36           ` Markus Armbruster
2010-06-15  9:12     ` Gerd Hoffmann
2010-06-15 18:03       ` Alex Williamson
2010-06-16  9:46 ` RFC qdev path semantics (was: [Qemu-devel] [RFC PATCH 0/5] Introduce canonical device hierarchy string) Markus Armbruster
2010-06-16 10:40   ` Paul Brook
2010-06-16 11:37   ` [Qemu-devel] Re: RFC qdev path semantics Jan Kiszka
2010-06-16 11:45     ` Paul Brook
2010-06-16 12:01       ` Jan Kiszka
2010-06-16 12:21         ` Paul Brook
2010-06-16 13:50           ` Jan Kiszka
2010-06-16 13:05   ` Markus Armbruster
2010-06-16 13:23     ` Paul Brook
2010-06-16 14:31       ` Markus Armbruster
2010-06-17 21:43   ` Alex Williamson
2010-06-17 22:01     ` Paul Brook
2010-06-17 22:34       ` Alex Williamson
2010-06-18  7:52     ` Gerd Hoffmann
2010-06-18 14:58   ` Markus Armbruster
2010-06-22 14:27   ` Anthony Liguori

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