Re: [Qemu-devel] [PATCH v4 0/6] spapr/xics: fix migration of older machine types

[David Gibson]

On Tue, Jun 13, 2017 at 01:59:29PM +0530, Nikunj A Dadhania wrote:
> Greg Kurz <address@hidden> writes:
> 
> > On Sun, 11 Jun 2017 17:38:42 +0800
> > David Gibson <address@hidden> wrote:
> >
> >> On Fri, Jun 09, 2017 at 05:09:13PM +0200, Greg Kurz wrote:
> >> > On Fri, 9 Jun 2017 20:28:32 +1000
> >> > David Gibson <address@hidden> wrote:
> >> >   
> >> > > On Fri, Jun 09, 2017 at 11:36:31AM +0200, Greg Kurz wrote:  
> >> > > > On Fri, 9 Jun 2017 12:28:13 +1000
> >> > > > David Gibson <address@hidden> wrote:
> >> > > >     
> >> > > > > On Thu, Jun 08, 2017 at 03:42:32PM +0200, Greg Kurz wrote:    
> >> > > > > > I've provided answers for all comments from the v3 review that I 
> >> > > > > > deliberately
> >> > > > > > don't address in v4.      
> >> > > > > 
> >> > > > > I've merged patches 1-4.  5 & 6 I'm still reviewing.
> >> > > > >     
> >> > > > 
> >> > > > Cool. FYI, I forgot to mention that I only tested with KVM.
> >> > > > 
> >> > > > I'm now trying with TCG and I hit various guest crash on
> >> > > > the destination (using your ppc-for-2.10 branch WITHOUT
> >> > > > my patches):    
> >> > > 
> >> > > Drat.  What's your reproducer for this crash?
> >> > >   
> >> > 
> >> > 1) start guest
> >> > 
> >> > qemu-system-ppc64 \
> >> >  -nodefaults -nographic -snapshot -no-shutdown -serial mon:stdio \
> >> >  -device virtio-net,netdev=netdev0,id=net0 \
> >> >  -netdev 
> >> > bridge,id=netdev0,br=virbr0,helper=/usr/libexec/qemu-bridge-helper \
> >> >  -device virtio-blk,drive=drive0,id=blk0 \
> >> >  -drive file=/home/greg/images/sle12-sp1-ppc64le.qcow2,id=drive0,if=none 
> >> > \
> >> >  -machine type=pseries,accel=tcg -cpu POWER8
> 
> Strangely, your command line does not have multiple threads. Need to see
> what is the side effect of enabling MTTCG by default here.
> 
> >> > 
> >> > 2) migrate
> >> > 
> >> > 3) destination crashes (immediately or after very short delay) or
> >> > hangs  
> >> 
> >> Ok.  I'll bisect it when I can, but you might well get to it first.
> >> 
> >> 
> >
> > Heh, maybe you didn't see in my mail but I did bisect:
> >
> > f0b0685d6694a28c66018f438e822596243b1250 is the first bad commit
> > commit f0b0685d6694a28c66018f438e822596243b1250
> > Author: Nikunj A Dadhania <address@hidden>
> > Date:   Thu Apr 27 10:48:23 2017 +0530
> >
> >     tcg: enable MTTCG by default for PPC64 on x86
> 
> Let me have a look at it.

Is this crash fixed by the patch from Thomas I merged yesterday?

-- 
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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