Re: [libvirt] CPU topology 'sockets' handling guest vs host

On my x86_64 host I have a pair of Quad core CPUs, each in a separate NUMA node. The virsh capabilities topology data reports this:  # virsh capabilities | xmllint  --xpath /capabilities/host/cpu -  <cpu>      <arch>x86_64</arch>      <model>Opteron_G3</model>      <vendor>AMD</vendor>      <topology sockets="1" cores="4" threads="1"/>      <feature name="osvw"/>      <feature name="3dnowprefetch"/>      <feature name="cr8legacy"/>      <feature name="extapic"/>      <feature name="cmp_legacy"/>      <feature name="3dnow"/>      <feature name="3dnowext"/>      <feature name="pdpe1gb"/>      <feature name="fxsr_opt"/>      <feature name="mmxext"/>      <feature name="ht"/>      <feature name="vme"/>    </cpu>  # virsh capabilities | xmllint  --xpath /capabilities/host/topology -  <topology>      <cells num="2">        <cell id="0">          <cpus num="4">            <cpu id="0"/>            <cpu id="1"/>            <cpu id="2"/>            <cpu id="3"/>          </cpus>        </cell>        <cell id="1">          <cpus num="4">            <cpu id="4"/>            <cpu id="5"/>            <cpu id="6"/>            <cpu id="7"/>          </cpus>        </cell>      </cells>  </topology> Note, it is reporting sockets=1, because sockets is the number of sockets *per* NUMA node. Now I try to figure the guest to match the host using:  <cpu>    <topology sockets='1' cores='4' threads='1'/>    <numa>      <cell cpus='0-3' memory='512000'/>      <cell cpus='4-7' memory='512000'/>    </numa>  </cpu> And I get:  error: Maximum CPUs greater than topology limit So, the XML checker is mistaking 'sockets' as the total number of sockets, rather than the per-node socket count. We need to fix this bogus check