[libvirt] [PATCH] qemu: Don't update count of vCPUs if hot-unplug has failed

[Peter Krempa]

After live change of cpu counts, the number of processor threads is
verified. This patch makes use of this approach to check if qemu ignored
the request for cpu hot-unplug and report an appropriate message.
---
 src/qemu/qemu_driver.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 39175f4..c4be130 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -3697,6 +3697,15 @@ static int qemuDomainHotplugVcpus(virQEMUDriverPtr driver,
         goto cleanup;
     }

+    /* check if hotplug has failed */
+    if (vcpus < oldvcpus && ncpupids == oldvcpus) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("qemu didn't unplug the vCPUs properly"));
+        vcpus = oldvcpus;
+        ret = -1;
+        goto cleanup;
+    }
+
     if (ncpupids != vcpus) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("got wrong number of vCPU pids from QEMU monitor. "
-- 
1.8.1