Re: [Qemu-devel] [Xen-devel] [PATCH] Remove hardcoded xen-platform device initialization

[Paolo Bonzini]

Il 18/06/2013 20:56, Stefano Stabellini ha scritto:
>> > 
>> > Ok. I guess we can have the ability to override the machine type in the VM 
>> > config, so you could still kick off an older qemu with a newer libxl - but 
>> > it sounds like the auto-discovery idea is a no-go then.
> xenfv-2.0 is a bad idea, like Paolo wrote, it should be possible to just
> use -M pc for HVM guests and retain -M xenpv for pv guests.
> 
> However it seems to me that we also need a way in libxl to find out
> whether QEMU is new enough for us to be able to use -M pc.
> We can't just assume that users will be able to figure out the magic
> rune they need to write in the VM config file to solve their VM crash at
> boot problem.
> 
> We could spawn an instance of QEMU just to figure out the QEMU version
> but we certainly cannot do that every time we start a new VM.
> Once we figure out the QEMU version the first time we could write it to
> xenstore so that the next time we don't have to go through the same
> process again.

Can you just assume that 4.4 requires QEMU 1.6 or newer?

Paolo