[PATCH v2] qemu-kvm: Remove extboot support

[Jan Kiszka <jan.kiszka@siemens.com>]

Except for booting from SCSI via the LSI controller, SeaBIOS has native
support for mass storage interfaces now. And SCSI can be worked around
via [1] - or someone finally adds the necessary bits to SeaBIOS if there
is a real need.

As there might be still scripts around that append "boot=on", continue
to parse it, but ignore it and issue a deprecation warning instead.

[1] http://thread.gmane.org/gmane.comp.emulators.qemu/78467

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Changes in v2:
 - restore accidentally removed VAPIC option ROM installation
 - continue to parse boot=on|off

 .gitignore                  |    1 -
 Makefile                    |    1 -
 Makefile.target             |    1 -
 blockdev.c                  |   15 +-
 blockdev.h                  |    2 -
 hw/extboot.c                |  123 --------
 hw/pc.c                     |   18 --
 hw/pc.h                     |    4 -
 pc-bios/optionrom/Makefile  |    2 +-
 pc-bios/optionrom/extboot.S |  691 -------------------------------------------
 qemu-config.c               |    2 +-
 qemu-options.hx             |    4 +-
 12 files changed, 7 insertions(+), 857 deletions(-)
 delete mode 100644 hw/extboot.c
 delete mode 100644 pc-bios/optionrom/extboot.S

diff --git a/.gitignore b/.gitignore
index 625f28e..ea2bd8a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -66,7 +66,6 @@ pc-bios/vgabios-pq/status
 pc-bios/optionrom/linuxboot.bin
 pc-bios/optionrom/multiboot.bin
 pc-bios/optionrom/multiboot.raw
-pc-bios/optionrom/extboot.bin
 pc-bios/optionrom/vapic.bin
 .stgit-*
 cscope.*
diff --git a/Makefile b/Makefile
index 936f130..f7f33a6 100644
--- a/Makefile
+++ b/Makefile
@@ -252,7 +252,6 @@ mpc8544ds.dtb \
 multiboot.bin linuxboot.bin \
 s390-zipl.rom \
 spapr-rtas.bin slof.bin
-BLOBS += extboot.bin
 BLOBS += vapic.bin
 else
 BLOBS=
diff --git a/Makefile.target b/Makefile.target
index 324b4f1..f84d8cb 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -229,7 +229,6 @@ obj-i386-y += mc146818rtc.o i8259.o pc.o
 obj-i386-y += cirrus_vga.o sga.o apic.o ioapic.o piix_pci.o
 obj-i386-y += vmport.o
 obj-i386-y += device-hotplug.o pci-hotplug.o smbios.o wdt_ib700.o
-obj-i386-y += extboot.o
 obj-i386-y += debugcon.o multiboot.o
 obj-i386-y += pc_piix.o
 obj-i386-$(CONFIG_KVM) += kvmclock.o
diff --git a/blockdev.c b/blockdev.c
index da74171..9678915 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -16,8 +16,6 @@
 #include "sysemu.h"
 #include "block_int.h"
 
-DriveInfo *extboot_drive = NULL;
-
 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
 
 static const char *const if_name[IF_COUNT] = {
@@ -237,7 +235,6 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
     int on_read_error, on_write_error;
     const char *devaddr;
     DriveInfo *dinfo;
-    int is_extboot = 0;
     int snapshot = 0;
     int ret;
 
@@ -356,10 +353,10 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         }
     }
 
-    is_extboot = qemu_opt_get_bool(opts, "boot", 0);
-    if (is_extboot && extboot_drive) {
-        fprintf(stderr, "qemu: two bootable drives specified\n");
-        return NULL;
+    if (qemu_opt_get(opts, "boot") != NULL) {
+        fprintf(stderr, "qemu-kvm: boot=on|off is deprecated and will be "
+                "ignored. Future versions will reject this parameter. Please "
+                "update your scripts.\n");
     }
 
     on_write_error = BLOCK_ERR_STOP_ENOSPC;
@@ -467,10 +464,6 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 
-    if (is_extboot) {
-        extboot_drive = dinfo;
-    }
-
     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 
     switch(type) {
diff --git a/blockdev.h b/blockdev.h
index 0a5144c..3587786 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -66,6 +66,4 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data);
 
-extern DriveInfo *extboot_drive;
-
 #endif
diff --git a/hw/extboot.c b/hw/extboot.c
deleted file mode 100644
index d517834..0000000
--- a/hw/extboot.c
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
- * Extended boot option ROM support.
- *
- * Copyright IBM, Corp. 2007
- *
- * Authors:
- *  Anthony Liguori   <aliguori@us.ibm.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2.  See
- * the COPYING file in the top-level directory.
- *
- */
-
-#include "hw.h"
-#include "pc.h"
-#include "isa.h"
-#include "block.h"
-
-/* Extended Boot ROM suport */
-
-union extboot_cmd
-{
-    uint16_t type;
-    struct {
-	uint16_t type;
-	uint16_t cylinders;
-	uint16_t heads;
-	uint16_t sectors;
-	uint64_t nb_sectors;
-    } query_geometry;
-    struct {
-	uint16_t type;
-	uint16_t nb_sectors;
-	uint16_t segment;
-	uint16_t offset;
-	uint64_t sector;
-    } xfer;
-};
-
-static void get_translated_chs(BlockDriverState *bs, int *c, int *h, int *s)
-{
-    bdrv_get_geometry_hint(bs, c, h, s);
-
-    if (*c <= 1024) {
-	*c >>= 0;
-	*h <<= 0;
-    } else if (*c <= 2048) {
-	*c >>= 1;
-	*h <<= 1;
-    } else if (*c <= 4096) {
-	*c >>= 2;
-	*h <<= 2;
-    } else if (*c <= 8192) {
-	*c >>= 3;
-	*h <<= 3;
-    } else {
-	*c >>= 4;
-	*h <<= 4;
-    }
-
-    /* what is the correct algorithm for this?? */
-    if (*h == 256) {
-	*h = 255;
-	*c = *c + 1;
-    }
-}
-
-static void extboot_write_cmd(void *opaque, uint32_t addr, uint32_t value)
-{
-    union extboot_cmd cmd;
-    BlockDriverState *bs = opaque;
-    int cylinders, heads, sectors, err;
-    uint64_t nb_sectors;
-    target_phys_addr_t pa = 0;
-    int blen = 0;
-    void *buf = NULL;
-
-    cpu_physical_memory_read((value & 0xFFFF) << 4, (uint8_t *)&cmd,
-                             sizeof(cmd));
-
-    if (cmd.type == 0x01 || cmd.type == 0x02) {
-	pa = cmd.xfer.segment * 16 + cmd.xfer.offset;
-        blen = cmd.xfer.nb_sectors * 512;
-        buf = qemu_memalign(512, blen);
-    }
-
-    switch (cmd.type) {
-    case 0x00:
-        get_translated_chs(bs, &cylinders, &heads, &sectors);
-	bdrv_get_geometry(bs, &nb_sectors);
-	cmd.query_geometry.cylinders = cylinders;
-	cmd.query_geometry.heads = heads;
-	cmd.query_geometry.sectors = sectors;
-	cmd.query_geometry.nb_sectors = nb_sectors;
-	break;
-    case 0x01:
-	err = bdrv_read(bs, cmd.xfer.sector, buf, cmd.xfer.nb_sectors);
-	if (err)
-	    printf("Read failed\n");
-
-        cpu_physical_memory_write(pa, buf, blen);
-
-	break;
-    case 0x02:
-        cpu_physical_memory_read(pa, buf, blen);
-
-	err = bdrv_write(bs, cmd.xfer.sector, buf, cmd.xfer.nb_sectors);
-	if (err)
-	    printf("Write failed\n");
-
-	break;
-    }
-
-    cpu_physical_memory_write((value & 0xFFFF) << 4, (uint8_t *)&cmd,
-                              sizeof(cmd));
-    if (buf)
-        free(buf);
-}
-
-void extboot_init(BlockDriverState *bs)
-{
-    register_ioport_write(0x405, 1, 2, extboot_write_cmd, bs);
-}
diff --git a/hw/pc.c b/hw/pc.c
index c2c0cc4..70e0d08 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -59,7 +59,6 @@
 #endif
 
 #define BIOS_FILENAME "bios.bin"
-#define EXTBOOT_FILENAME "extboot.bin"
 #define VAPIC_FILENAME "vapic.bin"
 
 #define PC_MAX_BIOS_SIZE (4 * 1024 * 1024)
@@ -1050,11 +1049,6 @@ void pc_memory_init(MemoryRegion *system_memory,
                                 (uint32_t)(-bios_size),
                                 bios);
 
-    if (extboot_drive) {
-        option_rom[nb_option_roms].name = g_strdup(EXTBOOT_FILENAME);
-        option_rom[nb_option_roms].bootindex = 0;
-        nb_option_roms++;
-    }
     option_rom[nb_option_roms].name = g_strdup(VAPIC_FILENAME);
     option_rom[nb_option_roms].bootindex = -1;
     nb_option_roms++;
@@ -1206,16 +1200,4 @@ void pc_pci_device_init(PCIBus *pci_bus)
     for (bus = 0; bus <= max_bus; bus++) {
         pci_create_simple(pci_bus, -1, "lsi53c895a");
     }
-
-    if (extboot_drive) {
-        DriveInfo *info = extboot_drive;
-        int cyls, heads, secs;
-
-        if (info->type != IF_IDE && info->type != IF_VIRTIO) {
-            bdrv_guess_geometry(info->bdrv, &cyls, &heads, &secs);
-            bdrv_set_geometry_hint(info->bdrv, cyls, heads, secs);
-        }
-
-        extboot_init(info->bdrv);
-    }
 }
diff --git a/hw/pc.h b/hw/pc.h
index f16ed25..db881b1 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -252,10 +252,6 @@ static inline bool isa_ne2000_init(int base, int irq, NICInfo *nd)
     return true;
 }
 
-/* extboot.c */
-
-void extboot_init(BlockDriverState *bs);
-
 /* e820 types */
 #define E820_RAM        1
 #define E820_RESERVED   2
diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
index da1a8b8..5c691da 100644
--- a/pc-bios/optionrom/Makefile
+++ b/pc-bios/optionrom/Makefile
@@ -16,7 +16,7 @@ QEMU_CFLAGS = $(CFLAGS)
 
 build-all: multiboot.bin linuxboot.bin
 
-build-all: extboot.bin vapic.bin
+build-all: vapic.bin
 
 %.img: %.o
 	$(call quiet-command,$(LD) -Ttext 0 -e _start -s -o $@ $<,"  Building $(TARGET_DIR)$@")
diff --git a/pc-bios/optionrom/extboot.S b/pc-bios/optionrom/extboot.S
deleted file mode 100644
index db6c2b6..0000000
--- a/pc-bios/optionrom/extboot.S
+++ /dev/null
@@ -1,691 +0,0 @@
-/*
- * Extended Boot Option ROM
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- *
- * Copyright IBM Corporation, 2007
- *   Authors: Anthony Liguori <aliguori@us.ibm.com>
- */
-
-#define OLD_INT19	(0x80 * 4)	/* re-use INT 0x80 BASIC vector */
-#define OLD_INT13	(0x81 * 4)	/* re-use INT 0x81 BASIC vector */
-
-.code16
-.text
-	.global _start
-_start:
-	.short 0xaa55
-	.byte (_end - _start) / 512
-	push %eax
-	push %ds
-
-	/* setup ds so we can access the IVT */
-	xor %ax, %ax
-	mov %ax, %ds
-
-	/* there is one more bootable HD */
-	incb 0x0475
-
-	/* save old int 19 */
-	mov (0x19*4), %eax
-	mov %eax, (OLD_INT19)
-
-	/* install out int 19 handler */
-	movw $int19_handler, (0x19*4)
-	mov %cs, (0x19*4+2)
-
-	pop %ds
-	pop %eax
-	lret
-
-int19_handler:
-	push %eax /* reserve space for lret */
-	push %eax
-	push %bx
-	push %cx
-	push %dx
-	push %ds
-
-	/* setup ds to access IVT */
-	xor %ax, %ax
-	mov %ax, %ds
-
-	/* save old int 13 to int 2c */
-	mov (0x13*4), %eax
-	mov %eax, (OLD_INT13)
-
-	/* install our int 13 handler */
-	movw $int13_handler, (0x13*4)
-	mov %cs, (0x13*4+2)
-
-	/* restore previous int $0x19 handler */
-	mov (OLD_INT19),%eax
-	mov %eax,(0x19*4)
-
-	/* write old handler as return address onto stack */
-	push %bp
-	mov %sp, %bp
-	mov %eax, 14(%bp)
-	pop %bp
-
-	pop %ds
-	pop %dx
-	pop %cx
-	pop %bx
-	pop %eax
-	lret
-
-#define FLAGS_CF	0x01
-
-/* The two macro below clear/set the carry flag to indicate the status
- * of the interrupt execution. It is not enough to issue a clc/stc instruction,
- * since the value of the flags register will be overwritten by whatever is
- * in the stack frame
- */
-.macro clc_stack
-	push %bp
-	mov %sp, %bp
-	/* 8 = 2 (bp, just pushed) + 2 (ip) + 3 (real mode interrupt frame) */
-	and $(~FLAGS_CF), 8(%bp)
-	pop %bp
-.endm
-
-.macro stc_stack
-	push %bp
-	/* 8 = 2 (bp, just pushed) + 2 (ip) + 3 (real mode interrupt frame) */
-	or $(FLAGS_CF), 8(%bp)
-	pop %bp
-.endm
-
-/* we clobber %bx */
-.macro alloca size
-	push %ds
-	push %bp
-	mov %sp, %bp  /* remember the current stack position */
-
-	mov %ss, %bx
-	mov %bx, %ds
-
-	sub \size, %sp
-	and $(~0x0F), %sp
-	mov %sp, %bx
-
-	push %bp
-	mov 0(%bp), %bp
-.endm
-
-/* we clobber %bp */
-.macro allocbpa size
-	mov %sp, %bp  /* remember the current stack position */
-	sub \size, %sp
-	and $(~0x0F), %sp
-	push %bp
-	mov %sp, %bp
-	add $2, %bp
-.endm
-
-.macro freea
-	pop %sp
-	add $2, %sp
-	pop %ds
-.endm
-
-.macro freebpa
-	pop %sp
-.endm
-
-.macro dump reg
-	push %ax
-	push %dx
-
-	mov \reg, %ax
-	mov $0x406, %dx
-	outw %ax, %dx
-
-	pop %dx
-	pop %ax
-.endm
-
-.macro callout value
-	push %bp
-	push %bx
-	mov %sp, %bp
-	alloca $16
-	push %ax
-	push %dx
-
-	mov %ax, 0(%bx)     /* ax */
-	mov 0(%bp), %ax     /* bx */
-	mov %ax, 2(%bx)
-	mov %cx, 4(%bx)     /* cx */
-	mov %dx, 6(%bx)     /* dx */
-	mov %si, 8(%bx)     /* si */
-	mov %ds, 10(%bx)    /* ds */
-	mov %es, 12(%bx)    /* ds */
-	movw \value, 14(%bx) /* value */
-
-	mov %bx, %ax
-	shr $4, %ax
-	mov %ds, %dx
-	add %dx, %ax
-
-	mov $0x407, %dx
-	outw %ax, %dx
-
-	pop %dx
-	pop %ax
-	freea
-	pop %bx
-	pop %bp
-.endm
-
-send_command:
-	push %bp
-	mov %sp, %bp
-	push %ax
-	push %bx
-	push %dx
-
-	mov 4(%bp), %ax
-	shr $4, %ax
-	and $0x0FFF, %ax
-	mov %ss, %bx
-	add %bx, %ax
-
-	mov $0x405, %dx
-	outw %ax, %dx
-
-	pop %dx
-	pop %bx
-	pop %ax
-	pop %bp
-
-	push %ax
-	mov 2(%bx), %ax
-	pop %ax
-
-	ret
-
-add32:  /* lo, hi, lo, hi */
-	push %bp
-	mov %sp, %bp
-
-	movw 4(%bp), %cx  /* hi */
-	movw 6(%bp), %dx  /* lo */
-
-	add  10(%bp), %dx
-	jnc 1f
-	add $1, %cx
-1:	add 8(%bp), %cx
-
-	pop %bp
-	ret
-
-mul32:  /* lo,      hi,     lo,     hi */
-	/* 10(%bp), 8(%bp), 6(%bp), 4(%bp) */
-	push %bp
-	mov %sp, %bp
-	push %ax
-	push %bx
-
-	xor %cx, %cx
-	xor %dx, %dx
-
-	/* for (i = 0; i < 16;) */
-	xor %bx, %bx
-0:
-	cmp $16, %bx
-	jge 2f
-
-	mov 6(%bp), %ax
-	and $1, %ax
-	cmp $1, %ax
-	jne 1f
-	push 10(%bp)
-	push 8(%bp)
-	push %dx
-	push %cx
-	call add32
-	add $8, %sp
-1:
-	shlw $1, 8(%bp)
-	movw 10(%bp), %ax
-	and $0x8000, %ax
-	cmp $0x8000, %ax
-	jne 1f
-	orw $1, 8(%bp)
-1:
-	shlw $1, 10(%bp)
-	shrw $1, 6(%bp)
-
-	/* i++) { */
-	add $1, %bx
-	jmp 0b
-
-2:
-	pop %bx
-	pop %ax
-	pop %bp
-	ret
-
-disk_reset:
-	movb $0, %ah
-	clc_stack
-	ret
-
-/* this really should be a function, not a macro but i'm lazy */
-.macro read_write_disk_sectors cmd
-	push %ax
-	push %bx
-	push %cx
-	push %dx
-	push %si
-
-	push %bp
-	sub $10, %sp
-	mov %sp, %bp
-
-	/* save nb_sectors */
-	mov %al, 6(%bp)
-	movb $0, 7(%bp)
-
-	/* save buffer */
-	mov %bx, 8(%bp)
-
-	/* cylinders */
-	xor %ax, %ax
-	mov %cl, %al
-	shl $2, %ax
-	and $0x300, %ax
-	mov %ch, %al
-	mov %ax, 0(%bp)
-
-	/* heads */
-	xor %ax, %ax
-	mov %dh, %al
-	mov %ax, 2(%bp)
-
-	/* sectors - 1 */
-	xor %ax, %ax
-	mov %cl, %al
-	and $0x3F, %al
-	sub $1, %ax
-	mov %ax, 4(%bp)
-
-	alloca $16
-
-	movw $0, 0(%bx) /* read c,h,s */
-	push %bx
-	call send_command
-	add $2, %sp
-
-	mov 6(%bx), %ax /* total_sectors */
-	mov 2(%bp), %si /* *= heads */
-	mul %si
-	add 4(%bp), %ax /* += sectors - 1 */
-
-	push 4(%bx) /* total_heads */
-	push $0
-	push 6(%bx) /* total_sectors */
-	push $0
-	call mul32
-	add $8, %sp
-
-	push 0(%bp) /* cylinders */
-	push $0
-	push %dx
-	push %cx
-	call mul32
-	add $8, %sp
-
-	add %ax, %dx
-	jnc 1f
-	add $1, %cx
-1:
-	freea
-
-	alloca $16
-
-	movw \cmd, 0(%bx) /* read */
-	movw 6(%bp), %ax /* nb_sectors */
-	movw %ax, 2(%bx)
-	movw %es, 4(%bx) /* segment */
-	movw 8(%bp), %ax /* offset */
-	mov %ax, 6(%bx)
-	movw %dx, 8(%bx) /* sector */
-	movw %cx, 10(%bx)
-	movw $0, 12(%bx)
-	movw $0, 14(%bx)
-
-	push %bx
-	call send_command
-	add $2, %sp
-
-	freea
-
-	add $10, %sp
-	pop %bp
-
-	pop %si
-	pop %dx
-	pop %cx
-	pop %bx
-	pop %ax
-
-	mov $0, %ah
-	clc_stack
-	ret
-.endm
-
-read_disk_sectors:
-	read_write_disk_sectors $0x01
-
-write_disk_sectors:
-	read_write_disk_sectors $0x02
-
-read_disk_drive_parameters:
-	push %bx
-
-	/* allocate memory for packet, pointer gets returned in bx */
-	alloca $16
-
-	/* issue command */
-	movw $0, 0(%bx) /* cmd = 0, read c,h,s */
-	push %bx
-	call send_command
-	add $2, %sp
-
-	/* normalize sector value */
-	movb 6(%bx), %cl
-	andb $0x3F, %cl
-	movb %cl, 6(%bx)
-
-	/* normalize cylinders */
-	subw $2, 2(%bx)
-
-	/* normalize heads */
-	subw $1, 4(%bx)
-
-	/* return code */
-	mov $0, %ah
-
-	/* cylinders */
-	movb 2(%bx), %ch
-	movb 3(%bx), %cl
-	shlb $6, %cl
-	andb $0xC0, %cl
-
-	/* sectors */
-	orb 6(%bx), %cl
-
-	/* heads */
-	movb 4(%bx), %dh
-
-	/* drives */
-	movb $1, %dl
-
-	/* status */
-	mov $0, %ah
-
-	freea
-
-	pop %bx
-
-	/* do this last since it's the most sensitive */
-	clc_stack
-	ret
-
-alternate_disk_reset:
-	movb $0, %ah
-	clc_stack
-	ret
-
-read_disk_drive_size:
-	push %bx
-	alloca $16
-
-	movw $0, 0(%bx) /* cmd = 0, read c,h,s */
-	push %bx
-	call send_command
-	add $2, %sp
-
-	/* cylinders - 1 to cx:dx */
-	mov 2(%bx), %dx
-	xor %cx, %cx
-	sub $1, %dx
-
-	/* heads */
-	push 4(%bx)
-	push $0
-	push %dx
-	push %cx
-	call mul32
-	add $8, %sp
-
-	/* sectors */
-	push 6(%bx)
-	push $0
-	push %dx
-	push %cx
-	call mul32
-	add $8, %sp
-
-	/* status */
-	mov $3, %ah
-
-	freea
-	pop %bx
-
-	clc_stack
-	ret
-
-check_if_extensions_present:
-	mov $0x30, %ah
-	mov $0xAA55, %bx
-	mov $0x07, %cx
-	clc_stack
-	ret
-
-.macro extended_read_write_sectors cmd
-	cmpb $10, 0(%si)
-	jg 1f
-	mov $1, %ah
-	stc_stack
-	ret
-1:
-	push %ax
-	push %bp
-	allocbpa $16
-
-	movw \cmd, 0(%bp) /* read */
-	movw 2(%si), %ax   /* nb_sectors */
-	movw %ax, 2(%bp)
-	movw 4(%si), %ax   /* offset */
-	movw %ax, 6(%bp)
-	movw 6(%si), %ax   /* segment */
-	movw %ax, 4(%bp)
-	movw 8(%si), %ax   /* block */
-	movw %ax, 8(%bp)
-	movw 10(%si), %ax
-	movw %ax, 10(%bp)
-	movw 12(%si), %ax
-	movw %ax, 12(%bp)
-	movw 14(%si), %ax
-	movw %ax, 14(%bp)
-
-	push %bp
-	call send_command
-	add $2, %sp
-
-	freebpa
-	pop %bp
-	pop %ax
-
-	mov $0, %ah
-	clc_stack
-	ret
-.endm
-
-extended_read_sectors:
-	extended_read_write_sectors $0x01
-
-extended_write_sectors:
-	extended_read_write_sectors $0x02
-
-get_extended_drive_parameters:
-	push %ax
-	push %bp
-	push %cx
-	push %dx
-
-	allocbpa $16
-
-	movw $0, 0(%bp) /* read c,h,s */
-	push %bp
-	call send_command
-	add $2, %sp
-
-	/* write size */
-	movw $26, 0(%si)
-
-	/* set flags to 2 */
-	movw $2, 2(%si)
-
-	/* cylinders */
-	mov 2(%bp), %ax
-	mov %ax, 4(%si)
-	xor %ax, %ax
-	mov %ax, 6(%si)
-
-	/* heads */
-	mov 4(%bp), %ax
-	mov %ax, 8(%si)
-	xor %ax, %ax
-	mov %ax, 10(%si)
-
-	/* sectors */
-	mov 6(%bp), %ax
-	mov %ax, 12(%si)
-	xor %ax, %ax
-	mov %ax, 14(%si)
-
-	/* set total number of sectors */
-	mov 8(%bp), %ax
-	mov %ax, 16(%si)
-	mov 10(%bp), %ax
-	mov %ax, 18(%si)
-	mov 12(%bp), %ax
-	mov %ax, 20(%si)
-	mov 14(%bp), %ax
-	mov %ax, 22(%si)
-
-	/* number of bytes per sector */
-	movw $512, 24(%si)
-
-	freebpa
-
-	pop %dx
-	pop %cx
-	pop %bp
-	pop %ax
-
-	mov $0, %ah
-	clc_stack
-	ret
-
-terminate_disk_emulation:
-	mov $1, %ah
-	stc_stack
-	ret
-
-int13_handler:
-	cmp $0x80, %dl
-	je 1f
-
-	/* write old handler as return address onto stack */
-	push %eax
-	push %eax
-	push %ds
-	push %bp
-	mov %sp, %bp
-	xor %ax, %ax
-	mov %ax, %ds
-	mov (OLD_INT13), %eax
-	mov %eax, 8(%bp)
-	pop %bp
-	pop %ds
-	pop %eax
-	lret
-1:
-	cmp $0x0, %ah
-	jne 1f
-	call disk_reset
-	iret
-1:
-	cmp $0x2, %ah
-	jne 1f
-	call read_disk_sectors
-	iret
-1:
-	cmp $0x8, %ah
-	jne 1f
-	call read_disk_drive_parameters
-	iret
-1:
-	cmp $0x15, %ah
-	jne 1f
-	call read_disk_drive_size
-	iret
-1:
-	cmp $0x41, %ah
-	jne 1f
-	call check_if_extensions_present
-	iret
-1:
-	cmp $0x42, %ah
-	jne 1f
-	call extended_read_sectors
-	iret
-1:
-	cmp $0x48, %ah
-	jne 1f
-	call get_extended_drive_parameters
-	iret
-1:
-	cmp $0x4b, %ah
-	jne 1f
-	call terminate_disk_emulation
-	iret
-1:
-	cmp $0x0d, %ah
-	jne 1f
-	call alternate_disk_reset
-	iret
-1:
-	cmp $0x03, %ah
-	jne 1f
-	call write_disk_sectors
-	iret
-1:
-	cmp $0x43, %ah
-	jne 1f
-	call extended_write_sectors
-	iret
-1:
-	int $0x18  /* boot failed */
-	iret
-
-.align 512, 0
-_end:
diff --git a/qemu-config.c b/qemu-config.c
index acab438..72e86b9 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -88,7 +88,7 @@ static QemuOptsList qemu_drive_opts = {
         },{
             .name = "boot",
             .type = QEMU_OPT_BOOL,
-            .help = "make this a boot drive",
+            .help = "(deprecated, ignored)",
         },
         { /* end of list */ }
     },
diff --git a/qemu-options.hx b/qemu-options.hx
index fbebab3..3a13533 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -135,7 +135,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "       [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
     "       [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
     "       [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
-    "       [,readonly=on|off][,boot=on|off]\n"
+    "       [,readonly=on|off]\n"
     "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
 STEXI
 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
@@ -183,8 +183,6 @@ host disk is full; report the error to the guest otherwise).
 The default setting is @option{werror=enospc} and @option{rerror=report}.
 @item readonly
 Open drive @option{file} as read-only. Guest write attempts will fail.
-@item boot=@var{boot}
-@var{boot} is "on" or "off" and allows for booting from non-traditional interfaces, such as virtio.
 @end table
 
 By default, writethrough caching is used for all block device.  This means that
-- 
1.7.3.4