[libvirt] [PATCH 6/6] virsh: vcpuinfo: Report proper vcpu numbers and data for offline VMs

[Peter Krempa]

If the VM is offline virsh attempted to at least report the pinning
information for the VM. This would not work properly now that the vcpus
can be sparse. Fix it by getting the vcpu states from the XML.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1375920
---
 tools/virsh-domain.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 100 insertions(+), 9 deletions(-)

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 84a4854..050e7fb 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -6310,37 +6310,125 @@ virshVcpuinfoPrintAffinity(vshControl *ctl,
 }


+static virBitmapPtr
+virshDomainGetVcpuBitmap(vshControl *ctl,
+                         virDomainPtr dom,
+                         bool inactive)
+{
+    unsigned int flags = 0;
+    char *def = NULL;
+    virBitmapPtr ret = NULL;
+    xmlDocPtr xml = NULL;
+    xmlXPathContextPtr ctxt = NULL;
+    xmlNodePtr *nodes = NULL;
+    xmlNodePtr old;
+    int nnodes;
+    size_t i;
+    unsigned int curvcpus = 0;
+    unsigned int maxvcpus = 0;
+    unsigned int vcpuid;
+    char *online = NULL;
+
+    if (inactive)
+        flags |= VIR_DOMAIN_XML_INACTIVE;
+
+    if (!(def = virDomainGetXMLDesc(dom, flags)))
+        goto cleanup;
+
+    if (!(xml = virXMLParseStringCtxt(def, _("(domain_definition)"), &ctxt)))
+        goto cleanup;
+
+    if (virXPathUInt("string(/domain/vcpu)", ctxt, &maxvcpus) < 0) {
+        vshError(ctl, "%s", _("Failed to retrieve maximum vcpu count"));
+        goto cleanup;
+    }
+
+    ignore_value(virXPathUInt("string(/domain/vcpu/@current)", ctxt, &curvcpus));
+
+    if (curvcpus == 0)
+        curvcpus = maxvcpus;
+
+    if (!(ret = virBitmapNew(maxvcpus)))
+        goto cleanup;
+
+    if ((nnodes = virXPathNodeSet("/domain/vcpus/vcpu", ctxt, &nodes)) <= 0) {
+        /* if the specific vcpu state is missing provide a fallback */
+        for (i = 0; i < curvcpus; i++)
+            ignore_value(virBitmapSetBit(ret, i));
+
+        goto cleanup;
+    }
+
+    old = ctxt->node;
+
+    for (i = 0; i < nnodes; i++) {
+        ctxt->node = nodes[i];
+
+        if (virXPathUInt("string(@id)", ctxt, &vcpuid) < 0 ||
+            !(online = virXPathString("string(@enabled)", ctxt)))
+            continue;
+
+        if (STREQ(online, "yes"))
+            ignore_value(virBitmapSetBit(ret, vcpuid));
+
+        VIR_FREE(online);
+    }
+
+    ctxt->node = old;
+
+    if (virBitmapCountBits(ret) != curvcpus) {
+        vshError(ctl, "%s", _("Failed to retrieve vcpu state bitmap"));
+        virBitmapFree(ret);
+        ret = NULL;
+    }
+
+ cleanup:
+    VIR_FREE(online);
+    VIR_FREE(nodes);
+    xmlXPathFreeContext(ctxt);
+    xmlFreeDoc(xml);
+    VIR_FREE(def);
+    return ret;
+}
+
+
 static bool
 virshVcpuinfoInactive(vshControl *ctl,
                       virDomainPtr dom,
-                      int nvcpus,
                       int maxcpu,
                       bool pretty)
 {
     unsigned char *cpumaps = NULL;
     size_t cpumaplen;
     int ncpus;
-    size_t i;
+    virBitmapPtr vcpus = NULL;
+    ssize_t nextvcpu = -1;
     bool ret = false;
+    bool first = true;
+
+    if (!(vcpus = virshDomainGetVcpuBitmap(ctl, dom, true)))
+        goto cleanup;

     cpumaplen = VIR_CPU_MAPLEN(maxcpu);
-    cpumaps = vshMalloc(ctl, nvcpus * cpumaplen);
+    cpumaps = vshMalloc(ctl, virBitmapSize(vcpus) * cpumaplen);

-    if ((ncpus = virDomainGetVcpuPinInfo(dom, nvcpus,
+    if ((ncpus = virDomainGetVcpuPinInfo(dom, virBitmapSize(vcpus),
                                          cpumaps, cpumaplen,
                                          VIR_DOMAIN_AFFECT_CONFIG)) < 0)
         goto cleanup;

-    for (i = 0; i < ncpus; i++) {
-        if (i != 0)
+    while ((nextvcpu = virBitmapNextSetBit(vcpus, nextvcpu)) >= 0) {
+        if (!first)
             vshPrint(ctl, "\n");
+        first = false;

-        vshPrint(ctl, "%-15s %zu\n", _("VCPU:"), i);
+        vshPrint(ctl, "%-15s %zd\n", _("VCPU:"), nextvcpu);
         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"));

-        if (virshVcpuinfoPrintAffinity(ctl, VIR_GET_CPUMAP(cpumaps, cpumaplen, i),
+        if (virshVcpuinfoPrintAffinity(ctl,
+                                       VIR_GET_CPUMAP(cpumaps, cpumaplen, nextvcpu),
                                        maxcpu, pretty) < 0)
             goto cleanup;
     }
@@ -6348,6 +6436,7 @@ virshVcpuinfoInactive(vshControl *ctl,
     ret = true;

  cleanup:
+    virBitmapFree(vcpus);
     VIR_FREE(cpumaps);
     return ret;
 }
@@ -6386,8 +6475,10 @@ cmdVcpuinfo(vshControl *ctl, const vshCmd *cmd)
         if (info.state != VIR_DOMAIN_SHUTOFF)
             goto cleanup;

+        vshResetLibvirtError();
+
         /* for offline VMs we can return pinning information */
-        ret = virshVcpuinfoInactive(ctl, dom, info.nrVirtCpu, maxcpu, pretty);
+        ret = virshVcpuinfoInactive(ctl, dom, maxcpu, pretty);
         goto cleanup;
     }

-- 
2.10.0