x86: extend e820 early_res support 32bit -fix #3

introduce init_pg_table_start, so xen PV could specify the value.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index af65b2d..bf7c34a 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -1011,6 +1011,7 @@
 	 * clobbered.  The Launcher places our initial pagetables somewhere at
 	 * the top of our physical memory, so we don't need extra space: set
 	 * init_pg_tables_end to the end of the kernel. */
+	init_pg_tables_start = __pa(pg0);
 	init_pg_tables_end = __pa(pg0);
 
 	/* Load the %fs segment register (the per-cpu segment register) with
@@ -1064,9 +1065,9 @@
 	pm_power_off = lguest_power_off;
 	machine_ops.restart = lguest_restart;
 
-	/* Now we're set up, call start_kernel() in init/main.c and we proceed
+	/* Now we're set up, call i386_start_kernel() in head32.c and we proceed
 	 * to boot as normal.  It never returns. */
-	start_kernel();
+	i386_start_kernel();
 }
 /*
  * This marks the end of stage II of our journey, The Guest.