x86: connect guest creation with CONFIG_PV

This is a bit more complicated than the HVM case because system
domains have PV guest type. Leave them like that.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/common/domain.c

@@ -322,17 +322,36 @@ struct domain *domain_create(domid_t domid,
     }
 
     /* Sort out our idea of is_{pv,hvm}_domain(). */
-    if ( config && (config->flags & XEN_DOMCTL_CDF_hvm_guest) )
+    if ( config )
     {
+        if ( config->flags & XEN_DOMCTL_CDF_hvm_guest )
+        {
 #ifdef CONFIG_HVM
-        d->guest_type = guest_type_hvm;
+            d->guest_type = guest_type_hvm;
 #else
-        err = -EINVAL;
-        goto fail;
+            err = -EINVAL;
+            goto fail;
 #endif
+        }
+        else
+        {
+#ifdef CONFIG_PV
+            d->guest_type = guest_type_pv;
+#else
+            err = -EINVAL;
+            goto fail;
+#endif
+        }
     }
     else
+    {
+        /*
+         * At least the idle domain should be treated as PV domain
+         * because it uses PV context switch functions. To err on the
+         * safe side, leave all system domains to be guest_type_pv.
+         */
         d->guest_type = guest_type_pv;
+    }
 
     TRACE_1D(TRC_DOM0_DOM_ADD, d->domain_id);