diff -r 81c9213b3d39 xen/include/public/platform.h
--- a/xen/include/public/platform.h	Tue Nov 28 18:41:42 2006 +0000
+++ b/xen/include/public/platform.h	Thu Aug 30 14:18:04 2007 -0400
@@ -114,6 +114,19 @@ typedef struct xenpf_platform_quirk xenp
 typedef struct xenpf_platform_quirk xenpf_platform_quirk_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_platform_quirk_t);
 
+typedef uint64_t cputime_t;
+DEFINE_XEN_GUEST_HANDLE(cputime_t);
+#define XENPF_getidletime         40
+struct xenpf_getidletime {
+    /* IN variables. */
+    uint32_t           max_cpus;
+    XEN_GUEST_HANDLE(uint64_t) buffer;
+    /* OUT variables. */
+    uint32_t           num_cpus;
+};
+typedef struct xenpf_getidletime xenpf_getidletime_t;
+DEFINE_XEN_GUEST_HANDLE(xenpf_getidletime_t);
+
 struct xen_platform_op {
     uint32_t cmd;
     uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@@ -124,6 +137,7 @@ struct xen_platform_op {
         struct xenpf_read_memtype      read_memtype;
         struct xenpf_microcode_update  microcode;
         struct xenpf_platform_quirk    platform_quirk;
+        struct xenpf_getidletime       getidletime;
         uint8_t                        pad[128];
     } u;
 };
diff -r 81c9213b3d39 xen/arch/x86/platform_hypercall.c
--- a/xen/arch/x86/platform_hypercall.c	Tue Nov 28 18:41:42 2006 +0000
+++ b/xen/arch/x86/platform_hypercall.c	Thu Aug 30 14:18:12 2007 -0400
@@ -138,6 +138,31 @@ long do_platform_op(XEN_GUEST_HANDLE(xen
     }
     break;
 
+    case XENPF_getidletime:
+    {
+        uint32_t cpu;
+        uint32_t max_cpus = op->u.getidletime.max_cpus;
+        uint64_t idletime;
+
+        for_each_online_cpu (cpu) {
+            if ( cpu >= max_cpus )
+                break;
+
+            idletime = idle_vcpu[cpu]->runstate.time[RUNSTATE_running];
+
+            if ( copy_to_guest_offset(op->u.getidletime.buffer, cpu, &idletime, 1) ) {
+                ret = -EFAULT;
+                break;
+            }
+        }
+
+        op->u.getidletime.num_cpus = cpu;
+
+        if ( copy_to_guest(u_xenpf_op, op, 1) )
+            ret = -EFAULT;
+    }
+    break;
+
     default:
         ret = -ENOSYS;
         break;