arm: add support for vm_assist hypercall

Up to now the vm_assist hypercall hasn't been supported on ARM, as
there are only x86 specific features to switch. Add support of
vm_assist on ARM for future use.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>

xen/arch/arm/traps.c

@@ -1282,6 +1282,7 @@ static arm_hypercall_t arm_hypercall_table[] = {
     HYPERCALL(multicall, 2),
     HYPERCALL(platform_op, 1),
     HYPERCALL_ARM(vcpu_op, 3),
+    HYPERCALL(vm_assist, 2),
 };
 
 #ifndef NDEBUG

xen/include/asm-arm/config.h

@@ -199,6 +199,8 @@ extern unsigned long frametable_virt_end;
 #define watchdog_disable() ((void)0)
 #define watchdog_enable()  ((void)0)
 
+#define VM_ASSIST_VALID          (0)
+
 #endif /* __ARM_CONFIG_H__ */
 /*
  * Local variables: