cputune: Support cputune for xend driver

Not sure if it's the correct way to add cputune xml for xend driver,
and besides, seems "xm driver" and "xen hypervisor" also support
vcpu affinity, do we need to add support for them too?

src/xen/xend_internal.c

@@ -2233,11 +2233,12 @@ xenDaemonDomainSetVcpusFlags(virDomainPtr domain, unsigned int vcpus,
  */
 int
 xenDaemonDomainPinVcpu(virDomainPtr domain, unsigned int vcpu,
-                     unsigned char *cpumap, int maplen)
+                       unsigned char *cpumap, int maplen)
 {
     char buf[VIR_UUID_BUFLEN], mapstr[sizeof(cpumap_t) * 64];
-    int i, j;
+    int i, j, ret;
     xenUnifiedPrivatePtr priv;
+    virDomainDefPtr def = NULL;
 
     if ((domain == NULL) || (domain->conn == NULL) || (domain->name == NULL)
      || (cpumap == NULL) || (maplen < 1) || (maplen > (int)sizeof(cpumap_t))) {
@@ -2265,8 +2266,29 @@ xenDaemonDomainPinVcpu(virDomainPtr domain, unsigned int vcpu,
         mapstr[strlen(mapstr) - 1] = 0;
 
     snprintf(buf, sizeof(buf), "%d", vcpu);
-    return(xend_op(domain->conn, domain->name, "op", "pincpu", "vcpu", buf,
-                  "cpumap", mapstr, NULL));
+
+    ret = xend_op(domain->conn, domain->name, "op", "pincpu", "vcpu", buf,
+                  "cpumap", mapstr, NULL);
+
+    if (!(def = xenDaemonDomainFetch(domain->conn,
+                                     domain->id,
+                                     domain->name,
+                                     NULL)))
+        goto cleanup;
+
+    if (ret == 0) {
+        if (virDomainVcpupinAdd(def, cpumap, maplen, vcpu) < 0) {
+            virXendError(VIR_ERR_INTERNAL_ERROR,
+                         "%s", _("failed to add vcpupin xml entry"));
+            return (-1);
+        }
+    }
+
+    return ret;
+
+cleanup:
+    virDomainDefFree(def);
+    return -1;
 }
 
 /**