On Fri, Sep 23, 2016 at 12:39:19PM +0200, Paolo Bonzini wrote: > > > On 23/09/2016 12:12, Peter Xu wrote: > > On Fri, Sep 23, 2016 at 12:03:26PM +0200, Paolo Bonzini wrote: > >> > >> > >> On 23/09/2016 12:02, Peter Xu wrote: > >>> On Fri, Sep 23, 2016 at 11:27:09AM +0200, Paolo Bonzini wrote: > >>>>> Since the whole IOMMU feature is new and somewhat experimental, I think > >>>>> it's okay to just make EIM the default for >=2.8 machine types if KVM is > >>>>> on (using DEFINE_PROP_ON_OFF_AUTO; auto means true if KVM is on and > >>>>> false otherwise, and pc-2.7 would set eim=off). It means requiring > >>>>> kernel 4.8 by default, but I don't think it's a big deal. > >>> I think the problem is, even we have KVM support for x2apic, we are > >>> still losing QEMU part. And guests with cluster x2apic and >8 vcpus > >>> will not working properly on device interrupts, which can be very > >>> confusing to people (it can boot, but some devices just don't work > >>> properly, and they won't see useful information in guest dmesg). > >> > >> Yes, that's why I suggested EIM=on by default. > > > > I am confused. :( > > > > Why not we just keep people from that wrong configuration by default, > > until we have x2apic in QEMU? > > Do you mean Igor's patches? I expect that they will go in pretty much > at the same time as Radim's.
Ah! Yes we have x2apic all here... So I totally agree we should set it on as default. (My mistake of not noticing the truth) Thanks, -- peterx
