commit af521a0182a0d6867796c65b1b0cd83fb14032a9
Author: Jim Fehlig <jfehlig@novell.com>
Date:   Wed Jan 5 15:20:01 2011 -0700

    Add HAP to xen hypervisor capabilities
    
    xen-unstable c/s 16931 introduced a per-domain setting for hvm
    guests to enable/disable hardware assisted paging.  If disabled,
    software techniques such as shadow page tables are used.  If enabled,
    and the feature exists in underlying hardware, hardware support for
    paging is used.
    
    Xen does not provide a mechanism to discover the HAP capability, so
    we advertise its availability for hvm guests on Xen >= 3.3.

diff --git a/src/xen/xen_hypervisor.c b/src/xen/xen_hypervisor.c
index ead8ee9..229ef3d 100644
--- a/src/xen/xen_hypervisor.c
+++ b/src/xen/xen_hypervisor.c
@@ -2321,6 +2321,16 @@ xenHypervisorBuildCapabilities(virConnectPtr conn,
                                                 hv_minor > 0 ?
                                                 0 : 1)) == NULL)
                 goto no_memory;
+
+            /* Xen 3.3.x and beyond supports enabling/disabling
+             * hardware assisted paging.  Default is off.
+             */
+            if ((hv_major == 3 && hv_minor >= 3) || (hv_major > 3))
+                if (virCapabilitiesAddGuestFeature(guest,
+                                                   "hap",
+                                                   0,
+                                                   1) == NULL)
+                    goto no_memory;
         }
     }