x86 setup: initialize LDTR and TR to make life easier to Intel VT

Intel VT doesn't like to engage when the protected-mode state isn't
fully initialized.  Make life easier for it by initializing LDTR (to
null) and TR (to a dummy hunk of low memory which will never actually
be touched.)

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/x86/boot/pm.c b/arch/x86/boot/pm.c
index 09fb342cc62e..b23cbdc7d547 100644
--- a/arch/x86/boot/pm.c
+++ b/arch/x86/boot/pm.c
@@ -121,6 +121,10 @@ static void setup_gdt(void)
                 [GDT_ENTRY_BOOT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),
                 /* DS: data, read/write, 4 GB, base 0 */
                 [GDT_ENTRY_BOOT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),
+                /* TSS: 32-bit tss, 104 bytes, base 4096 */
+                /* We only have a TSS here to keep Intel VT happy;
+                   we don't actually use it for anything. */
+                [GDT_ENTRY_BOOT_TSS] = GDT_ENTRY(0x0089, 4096, 103),
         };
         /* Xen HVM incorrectly stores a pointer to the gdt_ptr, instead
            of the gdt_ptr contents.  Thus, make it static so it will