[libvirt] [PATCH] qemu: Check for maximum vcpus exceeding cpu topology

[Kothapally Madhu Pavan]

This patch will prevent guest to start when the maximum
vcpus are greater than cpu topology limit. Currently similar
checks do exist only during setvcpus. The patch adds the
missing check. The c9cb35c255222 reverted similar check to
avoid older configs from vanishing. The current patch adds
it in domain validation part to be consistent with the
original intent.

Signed-off-by: Kothapally Madhu Pavan <kmp at linux.vnet.ibm.com>
---
 src/qemu/qemu_process.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 184440d..f0d42b8 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -3738,6 +3738,13 @@ qemuValidateCpuCount(virDomainDefPtr def,
         return -1;
     }
 
+    if (def->cpu->sockets && virDomainDefGetVcpusMax(def) >
+        def->cpu->sockets * def->cpu->cores * def->cpu->threads) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("Maximum CPUs greater than topology limit"));
+        return -1;
+    }
+
     if (maxCpus > 0 && virDomainDefGetVcpusMax(def) > maxCpus) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                        _("Maximum CPUs greater than specified machine type limit"));