vcpuinfo: add the code to fallback to try new API

The "virsh vcpuinfo" command results in failure when the target domain
is inactive on KVM. This patch improves this behavior by adding the
fallback to invoke virDomainGetVcpupinInfo API in case of
virDomainGetVcpus API returns error and the target domain is inactive.
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>

tools/virsh.c

@@ -2909,10 +2909,11 @@ cmdVcpuinfo(vshControl *ctl, const vshCmd *cmd)
     virDomainPtr dom;
     virNodeInfo nodeinfo;
     virVcpuInfoPtr cpuinfo;
-    unsigned char *cpumap;
-    int ncpus;
+    unsigned char *cpumaps;
+    int ncpus, maxcpu;
     size_t cpumaplen;
     bool ret = true;
+    int n, m;
 
     if (!vshConnectionUsability(ctl, ctl->conn))
         return false;
@@ -2931,15 +2932,14 @@ cmdVcpuinfo(vshControl *ctl, const vshCmd *cmd)
     }
 
     cpuinfo = vshMalloc(ctl, sizeof(virVcpuInfo)*info.nrVirtCpu);
-    cpumaplen = VIR_CPU_MAPLEN(VIR_NODEINFO_MAXCPUS(nodeinfo));
-    cpumap = vshMalloc(ctl, info.nrVirtCpu * cpumaplen);
+    maxcpu = VIR_NODEINFO_MAXCPUS(nodeinfo);
+    cpumaplen = VIR_CPU_MAPLEN(maxcpu);
+    cpumaps = vshMalloc(ctl, info.nrVirtCpu * cpumaplen);
 
     if ((ncpus = virDomainGetVcpus(dom,
                                    cpuinfo, info.nrVirtCpu,
-                                   cpumap, cpumaplen)) >= 0) {
-        int n;
+                                   cpumaps, cpumaplen)) >= 0) {
         for (n = 0 ; n < ncpus ; n++) {
-            unsigned int m;
             vshPrint(ctl, "%-15s %d\n", _("VCPU:"), n);
             vshPrint(ctl, "%-15s %d\n", _("CPU:"), cpuinfo[n].cpu);
             vshPrint(ctl, "%-15s %s\n", _("State:"),
@@ -2952,8 +2952,8 @@ cmdVcpuinfo(vshControl *ctl, const vshCmd *cmd)
                 vshPrint(ctl, "%-15s %.1lfs\n", _("CPU time:"), cpuUsed);
             }
             vshPrint(ctl, "%-15s ", _("CPU Affinity:"));
-            for (m = 0 ; m < VIR_NODEINFO_MAXCPUS(nodeinfo) ; m++) {
-                vshPrint(ctl, "%c", VIR_CPU_USABLE(cpumap, cpumaplen, n, m) ? 'y' : '-');
+            for (m = 0; m < maxcpu; m++) {
+                vshPrint(ctl, "%c", VIR_CPU_USABLE(cpumaps, cpumaplen, n, m) ? 'y' : '-');
             }
             vshPrint(ctl, "\n");
             if (n < (ncpus - 1)) {
@@ -2961,14 +2961,34 @@ cmdVcpuinfo(vshControl *ctl, const vshCmd *cmd)
             }
         }
     } else {
-        if (info.state == VIR_DOMAIN_SHUTOFF) {
-            vshError(ctl, "%s",
-                     _("Domain shut off, virtual CPUs not present."));
+        if (info.state == VIR_DOMAIN_SHUTOFF &&
+            (ncpus = virDomainGetVcpupinInfo(dom, info.nrVirtCpu,
+                                             cpumaps, cpumaplen,
+                                             VIR_DOMAIN_AFFECT_CONFIG)) >= 0) {
+
+            /* fallback plan to use virDomainGetVcpupinInfo */
+
+            for (n = 0; n < ncpus; n++) {
+                vshPrint(ctl, "%-15s %d\n", _("VCPU:"), n);
+                vshPrint(ctl, "%-15s %s\n", _("CPU:"), _("N/A"));
+                vshPrint(ctl, "%-15s %s\n", _("State:"), _("N/A"));
+                vshPrint(ctl, "%-15s %s\n", _("CPU time"), _("N/A"));
+                vshPrint(ctl, "%-15s ", _("CPU Affinity:"));
+                for (m = 0; m < maxcpu; m++) {
+                    vshPrint(ctl, "%c",
+                             VIR_CPU_USABLE(cpumaps, cpumaplen, n, m) ? 'y' : '-');
+                }
+                vshPrint(ctl, "\n");
+                if (n < (ncpus - 1)) {
+                    vshPrint(ctl, "\n");
+                }
+            }
+        } else {
+            ret = false;
         }
-        ret = false;
     }
 
-    VIR_FREE(cpumap);
+    VIR_FREE(cpumaps);
     VIR_FREE(cpuinfo);
     virDomainFree(dom);
     return ret;