Re: [Qemu-devel] 1.1.1 -> 1.1.2 migrate /managedsave issue

[Philipp Hahn]

Hello Doug,

On Tuesday 23 October 2012 22:38:47 Doug Goldstein wrote:
> >>> qemu: warning: error while loading state for instance 0x0 of device
> >>> 'ram' load of migration failed
...
> >> I diagnosed that using gdb to single step kvm until I found
> >> hw/pci.c#get_pci_config_device() returning -EINVAL.
...
> But yes I can confirm that
> vmstate_load_state() which is calling field->info->get() which is
> calling get_pci_config_device() is returning -EINVAL.
...
> Any recommendations to fix this? Or do I need to kill the saved state
> and start over?

For start try to re-get the old PXE ROM files, that is for Debian re-install 
the old etherboot-qemu or an older Version of the ipxe-qemu package. If that 
then works again, you can go further. Otherwise you need to get the exact 
index "i" where get_pci_config_device() returns -EINVAL and match that with 
the PCI spec. For short see hw/pci_regs.h.


For our Debian based UCS distribution I patched qemu(-kvm) to use the old 
image files (which are still available and installed in parallel to the new 
files) if the pc-level is 0.14 or lower (which is the version we currently 
ship; only our next release will switch to 1.1.2).

I've attached my patch FYI. That is only a work around until QEMU provides a 
real solution. If you've used an e1000, that is not enougth because some more 
PCI configuration bits (PCI_STATUS_CAP_LIST) were changed in an incompatible 
way.

If I remember correctly there was a different bug report, where changed PCI 
bits were also responsible for breaking saved states: Some PCI devices were 
changed to multi-function devices (or the other way around), which also 
breaks loading of previous saved stated. I think it was a bug in libvirt 
which started adding an explicit "multifunction=on", while the save was done 
using an implicit "multifinction=off". 
(<https://forge.univention.org/bugzilla/show_bug.cgi?id=22877#c6> in our 
German BZ)

Sincerely
Philipp Hahn
-- 
Philipp Hahn           Open Source Software Engineer      address@hidden
Univention GmbH        be open.                       fon: +49 421 22 232- 0
Mary-Somerville-Str.1  D-28359 Bremen                 fax: +49 421 22 232-99
                                                   http://www.univention.de/

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