RE: [Xen-devel] [RFC] Disable xen platform device when it is not needed.

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

> 
> I plan to create the patch to disable xen platform device when it
> is not needed. Please let me know if anyone has a comment.
> 
> Windows guest shows xen platform device as unknown
> device with "!" mark in the device manager, when PV drivers are not
> loaded. So I'd like to disable xen platform device.
> 
> If following conditions are all true, I will disable xen platform
> device. Otherwise, xen platform device will be enabled.
> 
>     - All entries in "disk" parameter have "ioemu:" prefix in DEV
field.
>         Example:
>         disk = [ '/var/images/guest.img,ioemu:hda,w',
',ioemu:hdc:cdrom,r'
> ]
> 
>     - All entries in "vif" parameter have "type=ioemu".
>         Example:
>         vif = [ 'type=ioemu, bridge=eth0', 'type=ioemu, bridge=eth1' ]
> 
>     - "vscsi" parameter is not specified.

I still leave my disks and network as ioemu even when using PV drivers,
as I simply need to use the /NOGPLPV boot option to switch back to them.

I recommend you add a 'no_platform_pci=1' option or something like that,
rather than try and guess that the user doesn't want it.

I'm also not sure that xen will boot without the disks being in ioemu
mode, so using a non-ioemu disk for the situation where you want to use
PV drivers will not give you a bootable system.

James

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