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Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 f
From: |
Anthony PERARD |
Subject: |
Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD |
Date: |
Tue, 20 May 2014 15:45:10 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, May 19, 2014 at 12:04:14PM +0000, Chen, Tiejun wrote:
> > -----Original Message-----
> > From: Gerd Hoffmann [mailto:address@hidden
> > Sent: Monday, May 19, 2014 7:23 PM
> > To: Chen, Tiejun
> > Cc: address@hidden; address@hidden;
> > address@hidden; address@hidden; address@hidden;
> > address@hidden; Kay, Allen M; address@hidden;
> > address@hidden; address@hidden; Zhang, Yang Z
> > Subject: Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve
> > 00:02.0 for INTEL IGD
> >
> > Hi,
> >
> > > I think '-vga none' just guarantees the qemu vga cards doesn't occupy
> > > 00:02.0, but this doesn't mean others use this specific slot since in
> > > qemu internal, we always pass -1 to assign a slot automatically to
> > > register a PCI device. So in some cases, we can't get this slot as we
> > > expect since that is already assigned previously before we need this.
> >
> > Yes, -vga, -net nic, -drive if=scsi (maybe more) can internally create pci
> > devices
> > with auto slot assignment, which will occupy slot 2 indeed.
> > Use -device instead to create the devices.
> >
>
> Are you saying we have to create the devices explicitly when we want to work
> IGD vga with passthrough? But how to make sure all user know this workable
> way? Maybe you suggest we should document somewhere.
>
> > > PCI: slot 2 function 0 not available for xen-pci-passthrough, in use
> > > by xen-platform
> >
> > Ah, the xen platform device. /me looks. Ah, pc_xen_hvm_init creates this
> > automatically. Two options here IMHO:
> >
> > (1) Just move it somewhere else explicitly. For example slot 3, or
> > make it a southbridge function (say 00:01.7).
> > (2) Don't create it automatically, instead expect management add it
> > if needed, using -device xen-plaform,addr=...
> >
> > I personally would suggest to go for #2. As far I know the platform device
> > is
> > only needed if you want attach xenbus devices to the guest (correct?), so
> > creating virtual machines without the xen platform device is a valid use
> > case
> > and you should allow it.
> >
>
> Looks you recommend we should change current xen platform design, I'm not
> sure if something in libxl also need to be modified. Especially, this may not
> be compatible with those old xen version. And especially, how to guarantee no
> one occupy 00:02.0 in the future with auto assign?
Hi,
Libxl knows how to create a guest without xen-platform, but I think this
can work only from QEMU 1.6 (which Xen 4.4 use).
So, using the options below with libxl would put the xen-platform device
away from the 00:02 slot.
xen_platform_pci=0
device_model_args_hvm = [ '-device', 'xen-platform,addr=0x3' ]
--
Anthony PERARD
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, (continued)
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Gerd Hoffmann, 2014/05/19
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Daniel P. Berrange, 2014/05/19
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Chen, Tiejun, 2014/05/21
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Chen, Tiejun, 2014/05/21
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Gerd Hoffmann, 2014/05/22
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Chen, Tiejun, 2014/05/22
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Gerd Hoffmann, 2014/05/22
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Michael S. Tsirkin, 2014/05/22
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Chen, Tiejun, 2014/05/22
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Konrad Rzeszutek Wilk, 2014/05/22
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD,
Anthony PERARD <=
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, Chen, Tiejun, 2014/05/20
[Qemu-devel] [v2][PATCH 5/8] xen, gfx passthrough: create intel isa bridge, Tiejun Chen, 2014/05/16
[Qemu-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Tiejun Chen, 2014/05/16
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Konrad Rzeszutek Wilk, 2014/05/16
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Zhang, Yang Z, 2014/05/18
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Konrad Rzeszutek Wilk, 2014/05/19
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Chen, Tiejun, 2014/05/20
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Konrad Rzeszutek Wilk, 2014/05/20