diff -r b28ae5f00553 xen/arch/x86/boot/trampoline.S
--- a/xen/arch/x86/boot/trampoline.S	Tue Oct 23 09:26:43 2007 +0100
+++ b/xen/arch/x86/boot/trampoline.S	Wed Oct 24 16:58:23 2007 -0700
@@ -167,6 +167,8 @@ 1:      mov     $(BOOT_TRAMPOLINE>>4),%a
 
         /* Disable irqs before returning to protected mode. */
         cli
+        /* At least 1 BIOS requires GDT to be reloaded. */
+        lgdt    bootsym(gdt_48)
 
         /* Enter protected mode, and flush insn queue. */
         xor     %ax,%ax