Re: [libvirt-users] setvcpus --guest on windows

On 11/05/2014 10:50 AM, Thomas Stein wrote: > Am 04.11.14 17:55, schrieb Thomas Stein: >> Hello. >> >> Just a quick question. Is "setvcpus $windowsVM --guest 4" supposed to >> work? I have qemu-guest-agent (1.6.something) running inside a windows7 >> vm but all i get is: >> >> virsh # setvcpus windows7 --guest 4 >> error: invalid argument: requested vcpu count is greater than the count >> of enabled vcpus in the domain: 4 > 1 I'm not exactly sure how well setvcpus --guest will work (or not) with windows guests. But the way it works for Linux guest is by telling the guest to treat an available cpu as offline; for this to work, the host must provide that cpu. So the error message makes sense. >> >> The xml file looks like this: >> >> <vcpu placement='static' current='1'>4</vcpu> For --guest to have any chance of changing cpus from the guest perspective, you need something like <vcpu current='4'>4</vcpu> as your starting point, then tell the guest to offline 3 cpus shortly after boot, then later tell the guest to turn the cpus back on when you are ready to give it more power.

> > Another question regarding qemu-guest-agent. What if i have more then > one VM running on a host? Is the configuration for any of them the same > or do i have to adjust some settings? > > <channel type='unix'> > <source mode='bind' path='/var/lib/libvirt/qemu/f16x86_64.agent'/> > <target type='virtio' name='org.qemu.guest_agent.0'/> > <address type='virtio-serial' controller='0' bus='0' port='1'/> > </channel> > > I mean, do i have to use a different port or something for each VM? The <address> element of a guest XML is related to what the _guest_ sees, not what the host provides. So it is perfectly fine for multiple guests to see the same <address> (each sees their own virtual hardware, and could care less if some other guest has similar virtual hardware). Similarly for the name of the <target> element - each guest will see their own guest-agent channel at the name 'org.qemu.guest_agent.0'; this is a guest view, so it doesn't matter whether other guests happen to also pick the same name.