Red Hat Bugzilla – Bug 177633
Virtual CPU hotplug does not work
Last modified: 2007-11-30 17:11:20 EST
Description of problem:
Virtual CPU hotplug does not work; running
# xm vcpu-set guest1 2
against a domU "guest1" with 1 vcpu does not dynamically increase the vcpu
count. And if I set the vcpus to 2 in /etc/xen/guest1 (which *does* work), then
# xm vcpu-set guest1 1
fails to lower it again.
Version-Release number of selected component (if applicable):
Still appears to be broken in today's rawhide.
The lowering of cpus works for me.
Just look at /proc/cpuinfo from inside the guest domain.
Raising the number of vcpus beyond what the guest booted with does not work,
however. I'll take a look at the code...
It seems that the vcpus parameter in the config file sets the maximum number of
possible vcpus for the domain. You should be able to set the current vcpus to
any number at or below this value. The hv code does not support changing the
value, in any case.
* Can only create new VCPUs while the domain is not fully constructed
* (and hence not runnable). Xen needs auditing for races before
* removing this check.