libxl: prefer new location of nested_hvm in libxl_domain_build_info

If available, use b_info->nested_hvm instead of
b_info->u.hvm.nested_hvm. This will make nested HVM config available
also for PVH domains.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>

src/libxl/libxl_conf.c

@@ -455,7 +455,18 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
                     }
                 }
             }
-            libxl_defbool_set(&b_info->u.hvm.nested_hvm, hasHwVirt);
+#ifdef LIBXL_HAVE_BUILDINFO_NESTED_HVM
+            libxl_defbool_set(&b_info->nested_hvm, hasHwVirt);
+#else
+            if (hvm) {
+                libxl_defbool_set(&b_info->u.hvm.nested_hvm, hasHwVirt);
+            } else {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                        _("unsupported nested HVM setting for %s machine on this Xen version"),
+                        def->os.machine);
+                return -1;
+            }
+#endif
         }
 
         if (def->cpu && def->cpu->mode == VIR_CPU_MODE_CUSTOM) {

tests/libxlxml2domconfigdata/fullvirt-cpuid.json

@@ -21,11 +21,11 @@
         ],
         "sched_params": {
         },
+        "nested_hvm": "False",
         "type.hvm": {
             "pae": "True",
             "apic": "True",
             "acpi": "True",
-            "nested_hvm": "False",
             "nographic": "True",
             "vnc": {
                 "enable": "False"

tests/libxlxml2domconfigdata/vnuma-hvm.json

@@ -109,11 +109,11 @@
         "sched_params": {
 
         },
+        "nested_hvm": "True",
         "type.hvm": {
             "pae": "True",
             "apic": "True",
             "acpi": "True",
-            "nested_hvm": "True",
             "vga": {
                 "kind": "cirrus"
             },