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Commit 88089519 authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Ingo Molnar
Browse files

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: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent c4d9ba6d

arch/x86/boot/pm.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -121,6 +121,10 @@ static void setup_gdt(void) 
		[GDT_ENTRY_BOOT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),

		[GDT_ENTRY_BOOT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),

		/* DS: data, read/write, 4 GB, base 0 */

		/* DS: data, read/write, 4 GB, base 0 */

		[GDT_ENTRY_BOOT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),

		[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

	/* Xen HVM incorrectly stores a pointer to the gdt_ptr, instead

	   of the gdt_ptr contents.  Thus, make it static so it will

	   of the gdt_ptr contents.  Thus, make it static so it will

arch/x86/boot/pmjump.S

+7 −0
Original line number Original line Diff line number Diff line
@@ -36,6 +36,7 @@ protected_mode_jump: 
	addl	%ebx, 2f

	addl	%ebx, 2f





	movw	$__BOOT_DS, %cx

	movw	$__BOOT_DS, %cx

	movw	$__BOOT_TSS, %di





	movl	%cr0, %edx

	movl	%cr0, %edx

	orb	$1, %dl			# Protected mode (PE) bit

	orb	$1, %dl			# Protected mode (PE) bit
@@ -63,6 +64,9 @@ in_pm32: 
	# a valid stack if some debugging hack wants to use it.

	# a valid stack if some debugging hack wants to use it.

	addl	%ebx, %esp

	addl	%ebx, %esp





	# Set up TR to make Intel VT happy

	ltr	%di



	# Clear registers to allow for future extensions to the

	# Clear registers to allow for future extensions to the

	# 32-bit boot protocol

	# 32-bit boot protocol

	xorl	%ecx, %ecx

	xorl	%ecx, %ecx
@@ -71,6 +75,9 @@ in_pm32: 
	xorl	%ebp, %ebp

	xorl	%ebp, %ebp

	xorl	%edi, %edi

	xorl	%edi, %edi





	# Set up LDTR to make Intel VT happy

	lldt	%cx



	jmpl	*%eax			# Jump to the 32-bit entrypoint

	jmpl	*%eax			# Jump to the 32-bit entrypoint





	.size	in_pm32, .-in_pm32
 
	.size	in_pm32, .-in_pm32

include/asm-x86/segment.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -9,6 +9,9 @@ 
#define GDT_ENTRY_BOOT_DS	(GDT_ENTRY_BOOT_CS + 1)

#define GDT_ENTRY_BOOT_DS	(GDT_ENTRY_BOOT_CS + 1)

#define __BOOT_DS		(GDT_ENTRY_BOOT_DS * 8)

#define __BOOT_DS		(GDT_ENTRY_BOOT_DS * 8)





#define GDT_ENTRY_BOOT_TSS	(GDT_ENTRY_BOOT_CS + 2)

#define __BOOT_TSS		(GDT_ENTRY_BOOT_TSS * 8)



#ifdef CONFIG_X86_32

#ifdef CONFIG_X86_32

/*

/*

 * The layout of the per-CPU GDT under Linux:

 * The layout of the per-CPU GDT under Linux: