get virtualization capabilities

diff -r ed67f68ae2a7 tools/python/xen/lowlevel/xc/xc.c
@@ -767,6 +767,8 @@ static PyObject *pyxc_physinfo(XcObject 
     uint64_t free_heap;
     PyObject *ret_obj, *node_to_cpu_obj, *node_to_memory_obj;
     xc_cpu_to_node_t map[MAX_CPU_ID + 1];
+    char virt_cap[128], *p_virt=virt_cap;
+    const char *virt_capsname[] = {"hvm", "iommu"};
 
     set_xen_guest_handle(info.cpu_to_node, map);
     info.max_cpu_id = MAX_CPU_ID;

@@ -784,7 +786,14 @@ static PyObject *pyxc_physinfo(XcObject 
     if ( q > cpu_cap )
         *(q-1) = 0;
 
-    ret_obj = Py_BuildValue("{s:i,s:i,s:i,s:i,s:i,s:l,s:l,s:l,s:i,s:s}",
+    *p_virt = 0;
+    for ( i = 0; i < 2; i++ )
+        if ((info.virt_cap >> i) & 1)
+          p_virt += sprintf(p_virt, "%s ", virt_capsname[i]);
+    if (p_virt != virt_cap)
+      *(p_virt - 1) = 0;
+
+    ret_obj = Py_BuildValue("{s:i,s:i,s:i,s:i,s:i,s:l,s:l,s:l,s:i,s:s:s:s}",
                             "nr_nodes",         info.nr_nodes,
                             "max_cpu_id",       info.max_cpu_id,
                             "threads_per_core", info.threads_per_core,

@@ -794,7 +803,8 @@ static PyObject *pyxc_physinfo(XcObject 
                             "free_memory",      pages_to_kib(info.free_pages),
                             "scrub_memory",     pages_to_kib(info.scrub_pages),
                             "cpu_khz",          info.cpu_khz,
-                            "hw_caps",          cpu_cap);
+                            "hw_caps",          cpu_cap,
+                            "virt_caps",        virt_cap);
 
     max_cpu_id = info.max_cpu_id;
     if ( max_cpu_id > MAX_CPU_ID )

diff -r ed67f68ae2a7 xen/arch/x86/sysctl.c
@@ -29,6 +29,8 @@
 
 #define get_xen_guest_handle(val, hnd)  do { val = (hnd).p; } while (0)
 
+extern int hvm_enabled;
+
 long arch_do_sysctl(
     struct xen_sysctl *sysctl, XEN_GUEST_HANDLE(xen_sysctl_t) u_sysctl)
 {

@@ -59,6 +61,8 @@ long arch_do_sysctl(
         pi->cpu_khz          = cpu_khz;
         memset(pi->hw_cap, 0, sizeof(pi->hw_cap));
         memcpy(pi->hw_cap, boot_cpu_data.x86_capability, NCAPINTS*4);
+        pi->virt_cap         = hvm_enabled << XEN_SYSCTL_PHYSINFO_HVM_ENABLED;
+        pi->virt_cap        |= iommu_enabled << XEN_SYSCTL_PHYSINFO_IOMMU_ENABLED;
 
         max_array_ent = pi->max_cpu_id;
         pi->max_cpu_id = last_cpu(cpu_online_map);

diff -r ed67f68ae2a7 xen/include/public/sysctl.h
@@ -35,6 +35,9 @@
 #include "domctl.h"
 
 #define XEN_SYSCTL_INTERFACE_VERSION 0x00000006
+
+#define XEN_SYSCTL_PHYSINFO_HVM_ENABLED         0
+#define XEN_SYSCTL_PHYSINFO_IOMMU_ENABLED       1
 
 /*
  * Read console content from Xen buffer ring.

@@ -95,6 +98,12 @@ struct xen_sysctl_physinfo {
     uint64_aligned_t free_pages;
     uint64_aligned_t scrub_pages;
     uint32_t hw_cap[8];
+    /*
+    ** Flags to get the different vt processor features
+    ** virt_cap:0 -> hvm enable
+    ** virt_cap:1 -> iommu enable
+    */
+    uint32_t virt_cap;
 
     /* IN/OUT variables. */
     /*