Re: [libvirt] [PATCH 4/4] Check the kvm host cpu max limits in virConnectGetDomainCapabilities()

23 Jun 2016

      On Wed, 2016-06-15 at 09:58 +0000, Shivaprasad G Bhat wrote:
...
-    domCaps->maxvcpus = maxvcpus;
+    domCaps->maxvcpus = virQEMUCapsGetMachineMaxCpus(qemuCaps, domCaps-
machine);
+    if (virttype == VIR_DOMAIN_VIRT_KVM) {
+        hostmaxvcpus = virHostCPUGetKVMVCPUs(VIR_HOSTCPU_KVM_MAXVCPUS);
+        domCaps->suggestedvcpus =
virHostCPUGetKVMVCPUs(VIR_HOSTCPU_KVM_NR_VCPUS);
+        domCaps->maxvcpus = MIN(domCaps->maxvcpus, hostmaxvcpus);
+    }
Forgot to mention this yesterday: domCaps->suggestedvcpus
will have to be capped by hostmaxvcpus as well, because
otherwise you would end up with stuff like

  <vcpu max='1' suggested='160'/>

for the 'isapc' or 'xenpv' machine types.

-- 
Andrea Bolognani / Red Hat / Virtualization