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Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to sa
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state |
Date: |
Wed, 19 Jan 2011 18:53:50 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Jan 19, 2011 at 11:42:18AM -0600, Anthony Liguori wrote:
> On 01/19/2011 11:35 AM, Daniel P. Berrange wrote:
> >On Wed, Jan 19, 2011 at 10:53:30AM -0600, Anthony Liguori wrote:
> >>On 01/19/2011 03:48 AM, Gerd Hoffmann wrote:
> >>>On 01/18/11 18:09, Anthony Liguori wrote:
> >>>>On 01/18/2011 10:56 AM, Jan Kiszka wrote:
> >>>>>>The device model topology is 100% a hidden architectural detail.
> >>>>>This is true for the sysbus, it is obviously not the case for PCI and
> >>>>>similarly discoverable buses. There we have a guest-explorable topology
> >>>>>that is currently equivalent to the the qdev layout.
> >>>>But we also don't do PCI passthrough so we really haven't even explored
> >>>>how that maps in qdev. I don't know if qemu-kvm has attempted to
> >>>>qdev-ify it.
> >>>It is qdev-ified. It is a normal pci device from qdev's point of view.
> >>>
> >>>BTW: is there any reason why (vfio-based) pci passthrough couldn't
> >>>work with tcg?
> >>>
> >>>>The -device interface is a stable interface. Right now, you don't
> >>>>specify any type of identifier of the pci bus when you create a PCI
> >>>>device. It's implied in the interface.
> >>>Wrong. You can specify the bus you want attach the device to via
> >>>bus=<name>. This is true for *every* device, including all pci
> >>>devices. If unspecified qdev uses the first bus it finds.
> >>>
> >>>As long as there is a single pci bus only there is simply no need
> >>>to specify it, thats why nobody does that today.
> >>Right. In terms of specifying bus=, what are we promising re:
> >>compatibility? Will there always be a pci.0? If we add some
> >>PCI-to-PCI bridges in order to support more devices, is libvirt
> >>support to parse the hierarchy and figure out which bus to put the
> >>device on?
> >The answer to your questions probably differ depending on
> >whether '-nodefconfig' and '-nodefaults' are set on the
> >command line. If they are set, then I'd expect to only
> >ever see one PCI bus with name pci.0 forever more, unless
> >i explicitly ask for more. If they are not set, then you
> >might expect to see multiple PCI buses by appear by magic
>
> Yeah, we can't promise that. If you use -M pc, you aren't
> guaranteed a stable PCI bus topology even with
> -nodefconfig/-nodefaults.
That's why we never use '-M pc' when actually invoking QEMU.
If the user specifies 'pc' in the XML, we canonicalize that
to the versioned alternative like 'pc-0.12' before invoking
QEMU. We also expose the list of versioned machines to apps
so they can do canonicalization themselves if desired.
Regards,
Daniel
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, (continued)
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Anthony Liguori, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Daniel P. Berrange, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Anthony Liguori, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Daniel P. Berrange, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Anthony Liguori, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Daniel P. Berrange, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Anthony Liguori, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state,
Daniel P. Berrange <=
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Markus Armbruster, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Gleb Natapov, 2011/01/24
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Markus Armbruster, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Anthony Liguori, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Jan Kiszka, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Blue Swirl, 2011/01/19
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Jan Kiszka, 2011/01/20
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Blue Swirl, 2011/01/20
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Jan Kiszka, 2011/01/20
- Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state, Blue Swirl, 2011/01/20