virtinst: validate that the CPU topology is sane

The product of sockets * dies * cores * threads must be equal to the
vCPU count. While libvirt and QEMU will report this error scenario,
it makes sense to catch it in virt-install, so we can test our local
logic for setting defaults for topology.

This exposes some inconsistent configurations in the test suite.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

tests/data/cli/compare/virt-install-singleton-config-1.xml

@@ -37,7 +37,7 @@
   <cpu mode="custom" match="exact">
     <model fallback="forbid">Broadwell</model>
     <vendor>Intel</vendor>
-    <topology sockets="2" dies="1" cores="2" threads="2"/>
+    <topology sockets="2" dies="1" cores="2" threads="1"/>
     <feature policy="require" name="vme"/>
     <feature policy="require" name="ss"/>
     <feature policy="require" name="f16c"/>

tests/data/cli/compare/virt-install-singleton-config-3.xml

@@ -12,7 +12,7 @@
     <access mode="shared"/>
     <source type="anonymous"/>
   </memoryBacking>
-  <vcpu current="3" placement="auto">4</vcpu>
+  <vcpu current="3" placement="auto">6</vcpu>
   <sysinfo type="smbios">
     <bios>
       <entry name="vendor">Acme LLC</entry>

tests/test_cli.py

@@ -467,7 +467,7 @@ c = vinst.add_category("xml-comparsion", "--connect %(URI-KVM)s --noautoconsole
 c.add_compare("""
 --memory 1024
 --uuid 12345678-12F4-1234-1234-123456789AFA
---vcpus 4,cores=2,threads=2,dies=1,sockets=2 --cpuset=1,3-5
+--vcpus 4,cores=2,threads=1,dies=1,sockets=2 --cpuset=1,3-5
 --cpu host-copy
 --description \"foobar & baz\"
 --boot uefi,smbios_mode=emulate,boot1.dev=hd,boot.dev=network,initarg1=bar=baz,initarg=foo
@@ -573,7 +573,7 @@ memnode0.cellid=1,memnode0.mode=strict,memnode0.nodeset=2
 
 # Test the implied defaults for gl=yes setting virgl=on
 c.add_compare("""
---vcpus vcpu.current=3,maxvcpus=4,vcpu.placement=auto
+--vcpus vcpu.current=3,maxvcpus=6,vcpu.placement=auto
 --memory hotplugmemorymax=2048,hotplugmemoryslots=2
 --disk none
 --features apic.eoi=off,hap=on,hyperv.synic.state=on,hyperv.reset.state=off,hyperv.spinlocks.state=on,hyperv.spinlocks.retries=5678,pae=on,pmu.state=on,pvspinlock.state=off,smm.state=off,viridian=on,vmcoreinfo.state=on,vmport.state=off,kvm.hidden.state=on,hyperv.vapic.state=off,hyperv.relaxed.state=off,gic.version=host,kvm.hint-dedicated.state=on,kvm.poll-control.state=on,ioapic.driver=qemu

tests/test_misc.py

@@ -42,14 +42,22 @@ def test_misc_cpu_topology():
 
     cpu = virtinst.DomainCpu(conn)
     cpu.topology.cores = "4"
-    cpu.set_topology_defaults(9)
+    cpu.set_topology_defaults(8)
     assert get_top(cpu) == [2, 1, 4, 1]
 
     cpu = virtinst.DomainCpu(conn)
     cpu.topology.threads = "3"
-    cpu.set_topology_defaults(14)
+    cpu.set_topology_defaults(12)
     assert get_top(cpu) == [4, 1, 1, 3]
 
+    cpu = virtinst.DomainCpu(conn)
+    cpu.topology.threads = "3"
+    try:
+        cpu.set_topology_defaults(14)
+        assert False, "Topology unexpectedly validated"
+    except ValueError:
+        pass
+
     cpu = virtinst.DomainCpu(conn)
     cpu.topology.sockets = 5
     cpu.topology.cores = 2

virtinst/domain/cpu.py

@@ -41,6 +41,18 @@ class _CPUTopology(XMLBuilder):
         if not self.threads:
             self.threads = vcpus // self.total_vcpus()
 
+        if self.total_vcpus() != vcpus:
+            raise ValueError(_("Total CPUs implied by topology "
+                               "(sockets=%(sockets)d * dies=%(dies)d * cores=%(cores)d * threads=%(threads)d == %(total)d) "
+                               "does not match vCPU count %(vcpus)d") % {
+                                   "sockets": self.sockets,
+                                   "dies": self.dies,
+                                   "cores": self.cores,
+                                   "threads": self.threads,
+                                   "total": self.total_vcpus(),
+                                   "vcpus": vcpus,
+                               })
+
         return
 
     def total_vcpus(self):