On Thu, Jun 08, 2017 at 10:21:44AM +0200, Andrea Bolognani wrote: > On Thu, 2017-06-08 at 14:12 +1000, David Gibson wrote: > > > David, are these known issues in QEMU? Are they being tracked? > > > > It's not an issue in qemu, it's an issue in the hardware. > > > > The various bugs in DD1 silicon mean it really isn't compliant with > > the 3.00 architecture (nor, quite, with the earlier ones). For that > > reason we explicitly disable compatibility modes on a DD1 host. > > > > More specifically advertising architected mode compatibility causes > > the guest kernel not to turn on some vital DD1 workarounds, which > > makes it break horribly. > > Fair enough. That still doesn't account for the lack of > power9 compatibility mode, which AFAICT is simply not > defined at all in QEMU. Umm.. what? It's right there in target/ppc/compat.c. Or are you looking at downstream - maybe it hasn't been backported yet. > Are there plans to introduce it? Should I file a bug to > track it? > > > > I don't see much point in updating libvirt to cope with these > > > new compat modes when QEMU itself doesn't. > > > > Try TCG, it should work there. > > Not quite: > > $ /usr/libexec/qemu-kvm \ > -nodefaults \ > -M pseries,accel=tcg \ > -cpu host,compat=power8 > qemu-kvm: Unable to find CPU definition: host Oh, right, of course, the "host" cpu only exists with KVM. > I *can* make it work with > > $ /usr/libexec/qemu-kvm \ > -nodefaults \ > -M pseries,accel=tcg \ > -cpu POWER9,compat=power8 > VNC server running on ::1:5900 > > but that's not helpful because <cpu mode='host-model'/> > uses the former. The same was true with POWER8, though. > > > One more issue I've noticed: > > $ /usr/libexec/qemu-kvm \ > -nodefaults \ > -M pseries,accel=kvm \ > -cpu POWER9 > qemu-kvm: Unable to find sPAPR CPU Core definition > > Since the recommended configuration for POWER8 guests is > to use > > <cpu mode='custom'> > <model>POWER8</model> > </cpu> > > I would expect the above command line to work so that > POWER9 guests can be configured in a similar manner. That > seems bug-worthy to me, should I go ahead and file it? Uh, yeah. Again, I'm pretty sure that's already working upstream. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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