Use arbitrary_virt_to_machine() to deal with ioremapped pmd updates.

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

arch/x86/xen/mmu.c

@@ -233,7 +233,7 @@ static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
 	xen_mc_batch();
 
 	/* ptr may be ioremapped for 64-bit pagetable setup */
-	u.ptr = virt_to_machine(ptr).maddr;
+	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
 	u.val = pmd_val_ma(val);
 	xen_extend_mmu_update(&u);