kvm и варианты настроек под smp машинки

windows xp

<domain type='kvm'>
  <name>winxp.my</name>
  <uuid>b155eaf4-408f-279e-a5d4-75fb828cfe32</uuid>
  <memory>2097152</memory>
  <currentMemory>2097152</currentMemory>
  <vcpu>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-0.13'>hvm</type>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
    <bootmenu enable='yes'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu match='exact'>
    <model>phenom</model>
    <vendor>AMD</vendor>
    <topology sockets='4' cores='4' threads='4'/>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='3dnowprefetch'/>
    <feature policy='require' name='3dnowext'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='pdpe1gb'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='3dnow'/>
  </cpu>
  <clock offset='localtime'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-kvm</emulator>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw' cache='none'/>
      <source file='/home/iron/media/virtio-win-1.1.16.iso'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='1' unit='0'/>
    </disk>
    <disk type='block' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source dev='/dev/mapper/vg_ess-winxp.my'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
    <disk type='file' device='floppy'>
      <driver name='qemu' type='raw'/>
      <target dev='fda' bus='fdc'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    </disk>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <controller type='scsi' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </controller>
    <controller type='fdc' index='0'/>
    <interface type='network'>
      <mac address='52:54:00:d1:a2:1b'/>
      <source network='default'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='tablet' bus='usb'/>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes'/>
    <sound model='ac97'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </memballoon>
  </devices>
</domain>

толком нигде не могу понять, как правильно задавать значения threads cores etc. соотношения.