Am 18.06.2013 21:35, schrieb Stefano Stabellini: > On Tue, 18 Jun 2013, Paolo Bonzini wrote: >> Il 18/06/2013 20:56, Stefano Stabellini ha scritto: >>> 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? > > I would rather not make that assumption because we cannot control what > distro are going to package. I wouldn't want a distro to ship with Xen > HVM guests broken because they choose the wrong QEMU version. Of course > we could put that in the release notes, but there are lots of distros > out there and I am pretty sure that at least one of them is not going to > read them.
You could check for existence of the pc-i440fx-1.6 machine and infer that it is at least v1.6 (might break in some distant future of course and for current git commits until your changes get merged). Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
