qemuValidateDomainVCpuTopology: Always validate vcpu count against topology

Historically we've used QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS as witness
that the topology must cover the maximum number ov vcpus. qemu started
to enforce this in qemu-2.5, thus we can now always do the check.

This change also requires aligning the topology in certain test files.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_validate.c

@@ -759,6 +759,9 @@ qemuValidateDomainVCpuTopology(const virDomainDef *def, virQEMUCaps *qemuCaps)
 {
     unsigned int maxCpus = virQEMUCapsGetMachineMaxCpus(qemuCaps, def->virtType,
                                                         def->os.machine);
+    unsigned int topologycpus;
+    unsigned int granularity;
+    unsigned int numacpus;
 
     if (virDomainDefGetVcpus(def) == 0) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
@@ -773,42 +776,31 @@ qemuValidateDomainVCpuTopology(const virDomainDef *def, virQEMUCaps *qemuCaps)
         return -1;
     }
 
-    /* QEMU 2.7 (detected via the availability of query-hotpluggable-cpus)
-     * enforces stricter rules than previous versions when it comes to guest
-     * CPU topology. Verify known constraints are respected */
-    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS)) {
-        unsigned int topologycpus;
-        unsigned int granularity;
-        unsigned int numacpus;
-
-        /* Starting from QEMU 2.5, max vCPU count and overall vCPU topology
-         * must agree. We only actually enforce this with QEMU 2.7+, due
-         * to the capability check above */
-        if (virDomainDefGetVcpusTopology(def, &topologycpus) == 0) {
-            if (topologycpus != virDomainDefGetVcpusMax(def)) {
-                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                               _("CPU topology doesn't match maximum vcpu count"));
-                return -1;
-            }
-
-            numacpus = virDomainNumaGetCPUCountTotal(def->numa);
-            if ((numacpus != 0) && (topologycpus != numacpus)) {
-                VIR_WARN("CPU topology doesn't match numa CPU count; "
-                         "partial NUMA mapping is obsoleted and will "
-                         "be removed in future");
-            }
-        }
-
-        /* vCPU hotplug granularity must be respected */
-        granularity = qemuValidateDefGetVcpuHotplugGranularity(def);
-        if ((virDomainDefGetVcpus(def) % granularity) != 0) {
-            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                           _("vCPUs count must be a multiple of the vCPU hotplug granularity (%1$u)"),
-                           granularity);
+    /* Starting from QEMU 2.5, max vCPU count and overall vCPU topology must agree. */
+    if (virDomainDefGetVcpusTopology(def, &topologycpus) == 0) {
+        if (topologycpus != virDomainDefGetVcpusMax(def)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("CPU topology doesn't match maximum vcpu count"));
             return -1;
         }
     }
 
+    numacpus = virDomainNumaGetCPUCountTotal(def->numa);
+    if ((numacpus != 0) && (topologycpus != numacpus)) {
+        VIR_WARN("CPU topology doesn't match numa CPU count; "
+                 "partial NUMA mapping is obsoleted and will "
+                 "be removed in future");
+    }
+
+    /* vCPU hotplug granularity must be respected */
+    granularity = qemuValidateDefGetVcpuHotplugGranularity(def);
+    if ((virDomainDefGetVcpus(def) % granularity) != 0) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("vCPUs count must be a multiple of the vCPU hotplug granularity (%1$u)"),
+                       granularity);
+        return -1;
+    }
+
     if (ARCH_IS_X86(def->os.arch) &&
         virDomainDefGetVcpusMax(def) > QEMU_MAX_VCPUS_WITHOUT_EIM) {
         if (!qemuDomainIsQ35(def)) {

tests/qemuxml2argvdata/fd-memory-numa-topology2.args

@@ -14,7 +14,7 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-instance-00000092/.config \
 -accel kvm \
 -m size=29360128k \
 -overcommit mem-lock=off \
--smp 20,sockets=1,cores=8,threads=1 \
+-smp 20,sockets=1,cores=20,threads=1 \
 -object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram/-1-instance-00000092/ram-node0,share=off,prealloc=on,size=15032385536 \
 -numa node,nodeid=0,cpus=0-7,cpus=16-19,memdev=ram-node0 \
 -object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram/-1-instance-00000092/ram-node1,share=on,prealloc=on,size=15032385536 \

tests/qemuxml2argvdata/fd-memory-numa-topology2.xml

@@ -14,7 +14,7 @@
     <boot dev='hd'/>
   </os>
   <cpu>
-    <topology sockets='1' dies='1' cores='8' threads='1'/>
+    <topology sockets='1' dies='1' cores='20' threads='1'/>
     <numa>
       <cell id='0' cpus='0-7,16-19' memory='14680064' unit='KiB'/>
       <cell id='1' cpus='8-15' memory='14680064' unit='KiB' memAccess='shared'/>

tests/qemuxml2argvdata/fd-memory-numa-topology3.args

@@ -14,7 +14,7 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-instance-00000092/.config \
 -accel kvm \
 -m size=44040192k \
 -overcommit mem-lock=off \
--smp 32,sockets=1,cores=24,threads=1 \
+-smp 32,sockets=1,cores=32,threads=1 \
 -object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram/-1-instance-00000092/ram-node0,share=on,prealloc=on,size=15032385536 \
 -numa node,nodeid=0,cpus=0-1,cpus=6-31,memdev=ram-node0 \
 -object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram/-1-instance-00000092/ram-node1,share=on,prealloc=on,size=15032385536 \

tests/qemuxml2argvdata/fd-memory-numa-topology3.xml

@@ -14,7 +14,7 @@
     <boot dev='hd'/>
   </os>
   <cpu>
-    <topology sockets='1' dies='1' cores='24' threads='1'/>
+    <topology sockets='1' dies='1' cores='32' threads='1'/>
     <numa>
       <cell id='0' cpus='0-1,6-31' memory='14680064' unit='KiB'/>
       <cell id='1' cpus='2-3' memory='14680064' unit='KiB' memAccess='shared'/>