End-User Question: XP-Guest produces high load for no obvious reason

Hello everyone,

I'm not sure if this is the correct mailing list with my topic. But the website says that end user's questions are welcome. So please give me a hint if this is the wrong place.

On the host:

# rpm -qa | grep kvm
kvm-0.12.5-1.2.1.x86_64

# uname -a
Linux alphawkst 2.6.34.7-0.7-desktop #1 SMP PREEMPT 2010-12-13 11:13:53
+0100 x86_64 x86_64 x86_64 GNU/Linux

The guest is a Windows XP 32 Bit, and everything was fine until yesterday. For no obvious reason, as soon as the guest starts one of the two cpu cores has 100% load if started with -smp 1, and both cpu cores have 100% load if started with -smp 2. There is no process inside the guest that generates this load. Instead, the guest is idling at 0-5% (that's what the windows task manager gives in the status line).

The guest is started with:

# qemu-kvm -M pc-0.12 -enable-kvm -smp 2 -m 1024 -name XP2Use -uuid
ad148b2d-b99e-c9de-7c0c-4ab6b716f3ec -rtc base=localtime -boot c -drive
file=/var/lib/libvirt/images/XP2Use.img,if=ide,index=0,boot=on,format=raw,cache=unsafe
-net nic,model=rtl8139,vlan=0,macaddr=52:54:00:5d:a2:a5 -net tap -vnc
127.0.0.1:0 -k de -vga std -usbdevice tablet

The same happens if the machine is started via virt-manager, in which case I find the following in the process list:

# ps aux | grep qemu
root     12909  100 13.1 1231668 1076428 ?     Sl   12:36   0:20
/usr/bin/qemu-kvm -S -M pc-0.12 -enable-kvm -m 1024 -smp
1,sockets=1,cores=1,threads=1 -name XP2Use -uuid
ad148b2d-b99e-c9de-7c0c-4ab6b716f3ec -nodefaults -chardev
socket,id=monitor,path=/var/lib/libvirt/qemu/XP2Use.monitor,server,nowait
-mon chardev=monitor,mode=readline -rtc base=localtime -boot dc -drive
if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive
file=/var/lib/libvirt/images/XP2Use.img,if=none,id=drive-
ide0-0-0,boot=on,format=raw
-device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0
-device rtl8139,vlan=0,id=net0,mac=52:54:00:5d:a2:a5,bus=pci.0,addr=0x4
-net tap,fd=38,vlan=0,name=hostnet0 -chardev pty,id=serial0 -device
isa-serial,chardev=serial0 -usb -device usb-tablet,id=input0 -vnc
127.0.0.1:0 -k en-us -vga std -device virtio-balloon-
pci,id=balloon0,bus=pci.0,addr=0x3

Can anyone see a reason for this behavior?

And again, if I'm wrong here, please point me to the right place.

Thanks!

Andre Tann