Latest revision as of 23:11, 7 October 2013

Description

Attach a CPU to a running VM.

Functioning virt host and VM created on F20+.

Launch virt-manager. Start with a shutoff VM. Verify that the guest has a 'Channel qemu-ga' device listed in its hardware details.
In Details->CPU, change the Max CPUs to 4 and the Current CPUs to 1. Note: there's a bug in virt-manager where it doesn't update the 'current vcpus' UI. But it does actually make the change.
Start the VM, log in, open a terminal and su - to get root.
Verify qemu-ga is running in the guest:
```
ps axwww | grep qemu-ga
```
Verify only CPU is visible to the guest, this should only show 'cpu0': ls -d /sys/devices/system/cpu/cpu[0-9]
In virt-manager, change the current CPU allocation to 2, hit apply.
Back in the guest, run the 'ls' command again, you should now see cpu0 and cpu1.
Online the CPU with: echo 1 > /sys/devices/system/cpu/cpu1/online
Verify the CPU shows up in: cat /proc/cpuinfo

Note: Hot remove is not currently supported.

No obvious errors occur, all results are as indicated.

@@ Line 10: / Line 10: @@
 * Launch virt-manager. Start with a shutoff VM. Verify that the guest has a 'Channel qemu-ga' device listed in its hardware details.
-* In Details->CPU, change the Max CPUs to 4 and the Current CPUs to 1.
+* In Details->CPU, change the Max CPUs to 4 and the Current CPUs to 1. Note: there's a [https://bugzilla.redhat.com/show_bug.cgi?id=1016318 bug in virt-manager] where it doesn't update the 'current vcpus' UI. But it does actually make the change.
 * Start the VM, log in, open a terminal and <code>su -</code> to get root.
 * Verify qemu-ga is running in the guest: <pre>ps axwww | grep qemu-ga</pre>