[Xen-changelog] [xen-3.1-testing] x86: GDTR must be reset after using real-mode BIOS services. Some

["Xen patchbot-3.1-testing" <patchbot-3.1-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1193301996 -3600
# Node ID f983730bfc809f768506fbbb27b0c5a5ec3ea626
# Parent  bf8eacda088f61a6fd286456bd8ed6411bf648fb
x86: GDTR must be reset after using real-mode BIOS services. Some
BIOSes clobber GDTR. While we're here reset IDTR too, although it's
not really necessary.
Signed-off-by: John Byrne <john.l.byrne@xxxxxx>
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
xen-unstable changeset:   16215:0f86492f1a8c44dd723cae0ebe3af9f2a737dea5
xen-unstable date:        Thu Oct 25 09:43:42 2007 +0100
---
 xen/arch/x86/boot/trampoline.S |    4 ++++
 1 files changed, 4 insertions(+)

diff -r bf8eacda088f -r f983730bfc80 xen/arch/x86/boot/trampoline.S
--- a/xen/arch/x86/boot/trampoline.S    Tue Oct 23 14:50:57 2007 +0100
+++ b/xen/arch/x86/boot/trampoline.S    Thu Oct 25 09:46:36 2007 +0100
@@ -160,6 +160,10 @@ 1:      mov     $(BOOT_TRAMPOLINE>>4),%a
         /* Disable irqs before returning to protected mode. */
         cli
 
+        /* Reset GDT and IDT. Some BIOSes clobber GDTR. */
+        lidt    bootsym(idt_48)
+        lgdt    bootsym(gdt_48)
+
         /* Enter protected mode, and flush insn queue. */
         xor     %ax,%ax
         inc     %ax

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