Re: [libvirt] specifying cirrus ram size
On 03/18/2014 03:59 PM, Serge Hallyn wrote:
Hi,
In order to migrate a VM from an older system with qemu-kvm to a newer
one with qemu, the newer qemu needs to be told to use the same vga
ram size as qemu-kvm used, 8M.
virsh domxml-from-native suggests that the way to specify a
8mb cirrus vga ram size would be to add
<qemu:commandline>
<qemu:arg value='-global'/>
<qemu:arg value='cirrus-vga.vgamem_mb=8'/>
</qemu:commandline>
This points out a weakness in our code - <qemu:commandline> is
intentionally unsupported, which means our XML needs an actual parameter
for this, rather than forcing you back to qemu:commandline. Or maybe we
already have the parameter, in which case the bug is in the
domxml-from-native code for not recognizing this particular usage of
command line arguments. But a quick grep for vgamem_mb doesn't have any
hits in current src/qemu/qemu_command.c, so it looks like we don't
support it yet.
However whenever I edit a .xml to add this, it disappears.
When outputting <qemu:commandline> in domxml-from-native, you must also
output the xmlns directive that enables its use. domxml-from-native is
correctly doing it, but doing it at the very first <domain> which is
quite some distance away, so you probably missed that key point. See
http://libvirt.org/drvqemu.html#qemucommand
Am I doing something silly?
You're forgetting <domain type='qemu'
xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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