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Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device |
Date: |
Fri, 23 May 2014 11:11:10 +0100 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Fri, 23 May 2014, Paul Durrant wrote:
> > -----Original Message-----
> > From: Stefano Stabellini [mailto:address@hidden
> > Sent: 22 May 2014 14:57
> > To: Gerd Hoffmann
> > Cc: Paolo Bonzini; Stefano Stabellini; Paul Durrant; address@hidden;
> > Anthony Liguori; address@hidden
> > Subject: Re: [PATCH] xen: make xen-platform a default device
> >
> > On Thu, 22 May 2014, Gerd Hoffmann wrote:
> > > > > Given that libxl always passes -nodefaults to QEMU, this patch is
> > > > > going
> > > > > to effectively disable xen_platform_pci for all Xen users. It is not a
> > > > > good idea. With the patch applied a Xen user would have no way to
> > enable
> > > > > xen_platform_pci except for passing some magic command line runes
> > via
> > > > > device_model_args_hvm.
> > > >
> > > > In fact this code only runs for "-M xenfv". If you use "-M pc", the
> > > > xen-platform device has to be added manually. Perhaps it would be
> > > > worthwhile to do the opposite, i.e. add the xen-platform device to "-M
> > > > pc" if not using -nodefaults.
> > >
> > > /me looks at the code. Yes, all the differences between xenfv and pc
> > > machine types are guarded by if (xen_enabled()) these days, except for
> > > adding the platform device.
> > >
> > > So using the pc machine type should just work on xen, and give you a
> > > machine without the platform device. So it can be added via -device, at
> > > any slot, if needed. No need to patch qemu at all. Adding or not
> > > adding xen-platform can easily handled by libxl then, depending on the
> > > xen_platform_pci switch in the config file.
> >
> > I agree. Changing libxl to always use -M pc and using -device to add
> > xen-platform when needed sounds like the best option.
>
> Really? You opposed this before:
>
> http://lists.xen.org/archives/html/xen-devel/2013-06/msg01946.html
>
> stating that you wanted a mechanism to query the running version of QEMU
> before choosing the machine type.
Many QEMU releases have been made since then. I feel more comfortable
with using -M pc, especially given the alternatives that have been
proposed. Of course having a mechanism to query the running version of
QEMU would still be the safest solution.
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, (continued)
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Stefano Stabellini, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Gerd Hoffmann, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Paolo Bonzini, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Gerd Hoffmann, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Stefano Stabellini, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Paul Durrant, 2014/05/23
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device,
Stefano Stabellini <=
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Paul Durrant, 2014/05/23
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Stefano Stabellini, 2014/05/23
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Paul Durrant, 2014/05/23
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Stefano Stabellini, 2014/05/22
- Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Paolo Bonzini, 2014/05/22
Re: [Qemu-devel] [PATCH] xen: make xen-platform a default device, Fabio Fantoni, 2014/05/23