[Qemu-devel] Re: Live migration of x86-64 kvm guests broken?

[Ryan Harper <ryanh@us.ibm.com>]

* Jan Kiszka <jan.kiszka@siemens.com> [2009-12-02 12:07]:
> Ryan Harper wrote:
> > * Jan Kiszka <jan.kiszka@siemens.com> [2009-12-02 09:28]:
> >> Hi,
> >>
> >> I'm facing stalled x86-64 guests after live migration when using kvm
> >> (share disk images). This does not happen with x86-32 guests or when
> >> disabling kvm. Both qemu and qemu-kvm git heads are affected (recent
> >> vmstate fixes applied). Running I/O load during the migration (e.g. a
> >> simple "ls -R /") seems to trigger it reliably.
> >>
> >> Can anyone confirm / comment on this? Do we fail to restore some magic
> >> state that only long mode cares about?
> > 
> > Just tested upstream qemu.git (with vmstate fixes) and I could migrate
> > RHEL 5.3 64-bit guest with your light io load over localhost.  I'll try
> > remote hosts next.
> 
> Hell, too many variables. It looks like the kernel modules have some if
> not the ultimate impact: kvm-mod-2.6.31.6b on my 2.6.27 host works fine,
> kvm-kmod stable-2.6.32 as well as master cause troubles.
> 
> What is your host kernel and/or kvm module version?

Stock 64-bit Ubuntu Karmic:
% uname -a
Linux symmetry 2.6.31-15-generic #50-Ubuntu SMP Tue Nov 10 14:53:52 UTC 2009 x86_64 GNU/Linux

% modinfo kvm
filename:
/lib/modules/2.6.31-15-generic/kernel/arch/x86/kvm/kvm.ko
license:        GPL
author:         Qumranet
srcversion:     82D6B673524596F9CF3E84C
depends:        
vermagic:       2.6.31-15-generic SMP mod_unload modversions 
parm:           oos_shadow:bool

% modinfo kvm-intel
filename: /lib/modules/2.6.31-15-generic/kernel/arch/x86/kvm/kvm-intel.ko
license:        GPL
author:         Qumranet
srcversion:     8FEA479DFCD7F174DA7864E
depends:        kvm
vermagic:       2.6.31-15-generic SMP mod_unload modversions 
parm:           bypass_guest_pf:bool
parm:           vpid:bool
parm:           flexpriority:bool
parm:           ept:bool
parm:           emulate_invalid_guest_state:bool


-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ryanh@us.ibm.com