Archipelago » qemu

#

# Local APIC acceleration for Windows XP and related guests

#

# Copyright 2011 Red Hat, Inc. and/or its affiliates

#

# Author: Avi Kivity <avi@redhat.com>

#

# This work is licensed under the terms of the GNU GPL, version 2, or (at your

# option) any later version.  See the COPYING file in the top-level directory.

#

	.text 0

	.code16

.global _start

_start:

	.short 0xaa55

	.byte (_end - _start) / 512

	# clear vapic area: firmware load using rep insb may cause

	# stale tpr/isr/irr data to corrupt the vapic area.

	push %es

	push %cs

	pop %es

	xor %ax, %ax

	mov $vapic_size/2, %cx

	lea vapic, %di

	cld

	rep stosw

	pop %es

	mov $vapic_base, %ax

	out %ax, $0x7e

	lret

	.code32

vapic_size = 2*4096

.macro fixup delta=-4

777:

	.text 1

	.long 777b + \delta  - vapic_base

	.text 0

.endm

.macro reenable_vtpr

	out %al, $0x7e

.endm

.text 1

	fixup_start = .

.text 0

.align 16

vapic_base:

	.ascii "kvm aPiC"

	/* relocation data */

	.long vapic_base	; fixup

	.long fixup_start	; fixup

	.long fixup_end		; fixup

	.long vapic		; fixup

	.long vapic_size

vcpu_shift:

	.long 0

real_tpr:

	.long 0

	.long up_set_tpr	; fixup

	.long up_set_tpr_eax	; fixup

	.long up_get_tpr_eax	; fixup

	.long up_get_tpr_ecx	; fixup

	.long up_get_tpr_edx	; fixup

	.long up_get_tpr_ebx	; fixup

	.long 0 /* esp. won't work. */

	.long up_get_tpr_ebp	; fixup

	.long up_get_tpr_esi	; fixup

	.long up_get_tpr_edi	; fixup

	.long up_get_tpr_stack  ; fixup

	.long mp_set_tpr	; fixup

	.long mp_set_tpr_eax	; fixup

	.long mp_get_tpr_eax	; fixup

	.long mp_get_tpr_ecx	; fixup

	.long mp_get_tpr_edx	; fixup

	.long mp_get_tpr_ebx	; fixup

	.long 0 /* esp. won't work. */

	.long mp_get_tpr_ebp	; fixup

	.long mp_get_tpr_esi	; fixup

	.long mp_get_tpr_edi	; fixup

	.long mp_get_tpr_stack  ; fixup

.macro kvm_hypercall

	.byte 0x0f, 0x01, 0xc1

.endm

kvm_hypercall_vapic_poll_irq = 1

pcr_cpu = 0x51

.align 64

mp_get_tpr_eax:

	pushf

	cli

	reenable_vtpr

	push %ecx

	fs/movzbl pcr_cpu, %eax

	mov vcpu_shift, %ecx	; fixup

	shl %cl, %eax

	testb $1, vapic+4(%eax)	; fixup delta=-5

	jz mp_get_tpr_bad

	movzbl vapic(%eax), %eax ; fixup

mp_get_tpr_out:

	pop %ecx

	popf

	ret

mp_get_tpr_bad:

	mov real_tpr, %eax	; fixup

	mov (%eax), %eax

	jmp mp_get_tpr_out

mp_get_tpr_ebx:

	mov %eax, %ebx

	call mp_get_tpr_eax

	xchg %eax, %ebx

	ret

mp_get_tpr_ecx:

	mov %eax, %ecx

	call mp_get_tpr_eax

	xchg %eax, %ecx

	ret

mp_get_tpr_edx:

	mov %eax, %edx

	call mp_get_tpr_eax

	xchg %eax, %edx

	ret

mp_get_tpr_esi:

	mov %eax, %esi

	call mp_get_tpr_eax

	xchg %eax, %esi

	ret

mp_get_tpr_edi:

	mov %eax, %edi

	call mp_get_tpr_edi

	xchg %eax, %edi

	ret

mp_get_tpr_ebp:

	mov %eax, %ebp

	call mp_get_tpr_eax

	xchg %eax, %ebp

	ret

mp_get_tpr_stack:

	call mp_get_tpr_eax

	xchg %eax, 4(%esp)

	ret

mp_set_tpr_eax:

	push %eax

	call mp_set_tpr

	ret

mp_set_tpr:

	pushf

	push %eax

	push %ecx

	push %edx

	push %ebx

	cli

	reenable_vtpr

mp_set_tpr_failed:

	fs/movzbl pcr_cpu, %edx

	mov vcpu_shift, %ecx	; fixup

	shl %cl, %edx

	testb $1, vapic+4(%edx)	; fixup delta=-5

	jz mp_set_tpr_bad

	mov vapic(%edx), %eax	; fixup

	mov %eax, %ebx

	mov 24(%esp), %bl

	/* %ebx = new vapic (%bl = tpr, %bh = isr, %b3 = irr) */

	lock cmpxchg %ebx, vapic(%edx) ; fixup

	jnz mp_set_tpr_failed

	/* compute ppr */

	cmp %bh, %bl

	jae mp_tpr_is_bigger

mp_isr_is_bigger:

	mov %bh, %bl

mp_tpr_is_bigger:

	/* %bl = ppr */

	mov %bl, %ch   /* ch = ppr */

	rol $8, %ebx

	/* now: %bl = irr, %bh = ppr */

	cmp %bh, %bl

	ja mp_set_tpr_poll_irq

mp_set_tpr_out:

	pop %ebx

	pop %edx

	pop %ecx

	pop %eax

	popf

	ret $4

mp_set_tpr_poll_irq:

	mov $kvm_hypercall_vapic_poll_irq, %eax

	kvm_hypercall

	jmp mp_set_tpr_out

mp_set_tpr_bad:

	mov 24(%esp), %ecx

	mov real_tpr, %eax	; fixup

	mov %ecx, (%eax)

	jmp mp_set_tpr_out

up_get_tpr_eax:

	reenable_vtpr

	movzbl vapic, %eax ; fixup

	ret

up_get_tpr_ebx:

	reenable_vtpr

	movzbl vapic, %ebx ; fixup

	ret

up_get_tpr_ecx:

	reenable_vtpr

	movzbl vapic, %ecx ; fixup

	ret

up_get_tpr_edx:

	reenable_vtpr

	movzbl vapic, %edx ; fixup

	ret

up_get_tpr_esi:

	reenable_vtpr

	movzbl vapic, %esi ; fixup

	ret

up_get_tpr_edi:

	reenable_vtpr

	movzbl vapic, %edi ; fixup

	ret

up_get_tpr_ebp:

	reenable_vtpr

	movzbl vapic, %ebp ; fixup

	ret

up_get_tpr_stack:

	reenable_vtpr

	movzbl vapic, %eax ; fixup

	xchg %eax, 4(%esp)

	ret

up_set_tpr_eax:

	push %eax

	call up_set_tpr

	ret

up_set_tpr:

	pushf

	push %eax

	push %ecx

	push %ebx

	reenable_vtpr

up_set_tpr_failed:

	mov vapic, %eax	; fixup

	mov %eax, %ebx

	mov 20(%esp), %bl

	/* %ebx = new vapic (%bl = tpr, %bh = isr, %b3 = irr) */

	lock cmpxchg %ebx, vapic ; fixup

	jnz up_set_tpr_failed

	/* compute ppr */

	cmp %bh, %bl

	jae up_tpr_is_bigger

up_isr_is_bigger:

	mov %bh, %bl

up_tpr_is_bigger:

	/* %bl = ppr */

	mov %bl, %ch   /* ch = ppr */

	rol $8, %ebx

	/* now: %bl = irr, %bh = ppr */

	cmp %bh, %bl

	ja up_set_tpr_poll_irq

up_set_tpr_out:

	pop %ebx

	pop %ecx

	pop %eax

	popf

	ret $4

up_set_tpr_poll_irq:

	mov $kvm_hypercall_vapic_poll_irq, %eax

	kvm_hypercall

	jmp up_set_tpr_out

.text 1

	fixup_end = .

.text 0

/*

 * vapic format:

 *  per-vcpu records of size 2^vcpu shift.

 *     byte 0: tpr (r/w)

 *     byte 1: highest in-service interrupt (isr) (r/o); bits 3:0 are zero

 *     byte 2: zero (r/o)

 *     byte 3: highest pending interrupt (irr) (r/o)

 */

.text 2

.align 128

vapic:

. = . + vapic_size

.byte 0  # reserve space for signature

.align 512, 0

_end: