[libvirt] vcpupin: fix cpu affinity setting bug of qemu driver

[Taku Izumi]

There is the case where cpu affinites for vcpu of qemu doesn't work
correctly.
For example, if only one vcpupin setting entry is provided and its setting
is
not for vcpu0, it doesn't work.

   # virsh dumpxml VM
   ...
   <vcpu>4</vcpu>
   <cputune>
     <vcpupin vcpu='3' cpuset='9-11'/>
   </cputune>
   ...

   # virsh start VM
   Domain VM started

   # virsh vcpuinfo VM
   VCPU:           0
   CPU:            31
   State:          running
   CPU time:       2.5s
   CPU Affinity:   yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
   
   VCPU:           1
   CPU:            12
   State:          running
   CPU time:       0.9s
   CPU Affinity:   yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
   
   VCPU:           2
   CPU:            30
   State:          running
   CPU time:       1.5s
   CPU Affinity:   yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
   
   VCPU:           3
   CPU:            13
   State:          running
   CPU time:       1.7s
   CPU Affinity:   yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy


This patch fixes this problem.

Signed-off-by: Taku Izumi <izumi.taku at jp.fujitsu.com>
---
 src/qemu/qemu_process.c |   10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

Index: libvirt/src/qemu/qemu_process.c
===================================================================
--- libvirt.orig/src/qemu/qemu_process.c
+++ libvirt/src/qemu/qemu_process.c
@@ -1194,7 +1194,7 @@ qemuProcessSetVcpuAffinites(virConnectPt
     virNodeInfo nodeinfo;
     pid_t vcpupid;
     unsigned char *cpumask;
-    int vcpu, cpumaplen, hostcpus, maxcpu;
+    int vcpu, cpumaplen, hostcpus, maxcpu, n;
     unsigned char *cpumap = NULL;
     int ret = -1;
 
@@ -1223,14 +1223,12 @@ qemuProcessSetVcpuAffinites(virConnectPt
         return -1;
     }
 
-    for (vcpu = 0; vcpu < def->cputune.nvcpupin; vcpu++) {
-        if (vcpu != def->cputune.vcpupin[vcpu]->vcpuid)
-            continue;
-
+    for (n = 0; n < def->cputune.nvcpupin; n++) {
         int i;
+        vcpu =  def->cputune.vcpupin[n]->vcpuid;
 
         memset(cpumap, 0, cpumaplen);
-        cpumask = (unsigned char *)def->cputune.vcpupin[vcpu]->cpumask;
+        cpumask = (unsigned char *)def->cputune.vcpupin[n]->cpumask;
         vcpupid = priv->vcpupids[vcpu];
 
         /* Convert cpumask to bitmap here. */