x86: change write_gdt_entry signature.

This patch changes the write_gdt_entry function signature.
Instead of the old "a" and "b" parameters, it now receives
a pointer to a desc_struct, and the size of the entry being
handled. This is because x86_64 can have some 16-byte entries
as well as 8-byte ones.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
CC: Zachary Amsden <zach@vmware.com>
CC: Jeremy Fitzhardinge <Jeremy.Fitzhardinge.citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index b50c8ad..a633737 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -262,10 +262,10 @@
 /* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
  * then tell the Host to reload the entire thing.  This operation is so rare
  * that this naive implementation is reasonable. */
-static void lguest_write_gdt_entry(struct desc_struct *dt,
-				   int entrynum, u32 low, u32 high)
+static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
+				   const void *desc, int type)
 {
-	write_dt_entry(dt, entrynum, low, high);
+	native_write_gdt_entry(dt, entrynum, desc, type);
 	hcall(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES, 0);
 }