[libvirt] [PATCH] virsh: use virConnectGetDomainCapabilities with maxvcpus

[Peter Krempa]

From: Shivaprasad G Bhat <sbhat at linux.vnet.ibm.com>

virsh maxvcpus --type kvm output is useless on PPC. Also, in
commit e6806d79 we documented not rely on virConnectGetMaxVcpus
output. Fix the  maxvcpus to use virConnectGetDomainCapabilities
now to make it useful. The call is made to use the default emulator
binary and to check for the host machine and arch which is what the
command intends to show anyway.

Signed-off-by: Shivaprasad G Bhat <sbhat at linux.vnet.ibm.com>
---
 tools/virsh-host.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/tools/virsh-host.c b/tools/virsh-host.c
index 57f0c0e..2337ce8 100644
--- a/tools/virsh-host.c
+++ b/tools/virsh-host.c
@@ -606,18 +606,40 @@ static bool
 cmdMaxvcpus(vshControl *ctl, const vshCmd *cmd)
 {
     const char *type = NULL;
-    int vcpus;
+    int vcpus = -1;
+    char *caps = NULL;
+    xmlDocPtr xml = NULL;
+    xmlXPathContextPtr ctxt = NULL;
     virshControlPtr priv = ctl->privData;
+    bool ret = false;

     if (vshCommandOptStringReq(ctl, cmd, "type", &type) < 0)
         return false;

-    if ((vcpus = virConnectGetMaxVcpus(priv->conn, type)) < 0)
-        return false;
+    if ((caps = virConnectGetDomainCapabilities(priv->conn, NULL, NULL, NULL,
+                                                type, 0))) {
+        if (!(xml = virXMLParseStringCtxt(caps, _("(domainCapabilities)"), &ctxt)))
+            goto cleanup;
+
+        ignore_value(virXPathInt("string(./vcpu[1]/@max)", ctxt, &vcpus));
+    } else {
+        if (last_error && last_error->code != VIR_ERR_NO_SUPPORT)
+            goto cleanup;
+
+       vshResetLibvirtError();
+    }
+
+    if (vcpus < 0 && (vcpus = virConnectGetMaxVcpus(priv->conn, type)) < 0)
+        goto cleanup;

     vshPrint(ctl, "%d\n", vcpus);
+    ret = true;

-    return true;
+ cleanup:
+    xmlXPathFreeContext(ctxt);
+    xmlFreeDoc(xml);
+    VIR_FREE(caps);
+    return ret;
 }

 /*
-- 
2.10.0