lguest: move last_pages to lg_cpu

in our new model, pages are assigned to a virtual cpu, not to a guest.
We move it to the lg_cpu structure.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index f4f6df8..a87fca6 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -131,6 +131,10 @@
 	 * reference, it is destroyed before close() is called. */
 	cpu->mm = get_task_mm(cpu->tsk);
 
+	/* We remember which CPU's pages this Guest used last, for optimization
+	 * when the same Guest runs on the same CPU twice. */
+	cpu->last_pages = NULL;
+
 	return 0;
 }
 
@@ -192,10 +196,6 @@
 	if (err)
 		goto free_regs;
 
-	/* We remember which CPU's pages this Guest used last, for optimization
-	 * when the same Guest runs on the same CPU twice. */
-	lg->last_pages = NULL;
-
 	/* We keep our "struct lguest" in the file's private_data. */
 	file->private_data = lg;