Re: [Qemu-devel] Live migrate, inconsistent machine types - new machine type to fix?

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/07/2014 01:33, Alex Bligh ha scritto:
> I'm trying to migrate between a pc-1.0 machine on qemu 1.0 and a pc-1.0 machine on qemu-2.0. This appears not to work.
> 
> It looks to me as if at some point along the line the definition of pc-1.0 has changed (eek).
> 
> The machine was booted with the command line [1] below, then migrated (for the sake of ease including a full block device dump) to a file. I'm happy to provide this (it's a blank cirros image but on a 20GB disk so quite large).
> 
> Restoring the machine with the command line [2] (merely adding -machine pc-1.0 which is not the default for qemu-2.0) produces the error:
> Length mismatch: vga.vram: 1000000 in != 800000
> qemu: warning: error while loading state for instance 0x0 of device 'ram'
> load of migration failed

This is unfortunately a known difference between qemu-kvm and qemu.

> This can be fixed using command line [3] (adding an additional -global cirrus-vga.vgamem_mb=10) in which case it gets a little further.
> Length mismatch: 0000:00:03.0/virtio-net-pci.rom: 10000 in != 20000
> qemu: warning: error while loading state for instance 0x0 of device 'ram'
> load of migration failed

Looks like your source and destination machines have different iPXE
ROMs.  This could be a packaging problem in your distro.

Paolo