xen: add dom0_op hypercall

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

arch/x86/include/asm/xen/hypercall.h

@@ -45,6 +45,7 @@
 #include <xen/interface/xen.h>
 #include <xen/interface/sched.h>
 #include <xen/interface/physdev.h>
+#include <xen/interface/platform.h>
 
 /*
  * The hypercall asms have to meet several constraints:
@@ -298,6 +299,13 @@ HYPERVISOR_set_timer_op(u64 timeout)
 	return _hypercall2(long, set_timer_op, timeout_lo, timeout_hi);
 }
 
+static inline int
+HYPERVISOR_dom0_op(struct xen_platform_op *platform_op)
+{
+	platform_op->interface_version = XENPF_INTERFACE_VERSION;
+	return _hypercall1(int, dom0_op, platform_op);
+}
+
 static inline int
 HYPERVISOR_set_debugreg(int reg, unsigned long value)
 {