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* [PATCH 1/2] Add extboot to kvm-userspace
@ 2008-01-02 16:22 Anthony Liguori
       [not found] ` <119929095077-git-send-email-aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
  0 siblings, 1 reply; 4+ messages in thread
From: Anthony Liguori @ 2008-01-02 16:22 UTC (permalink / raw)
  To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f; +Cc: Anthony Liguori, Avi Kivity

extboot is an x86 Option ROM that passes through int13 functions to a VMM which
allows a VMM to expose an arbitrary block device as the primary BIOS disk.  It
can be used to boot SCSI or paravirtual devices.

Signed-off-by: Anthony Liguori <aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>

diff --git a/extboot/Makefile b/extboot/Makefile
new file mode 100644
index 0000000..1ea71a7
--- /dev/null
+++ b/extboot/Makefile
@@ -0,0 +1,21 @@
+OBJCOPY=objcopy
+
+CFLAGS=-Wall -Wstrict-prototypes -Werror -fomit-frame-pointer -fno-builtin \
+       -fno-stack-protector
+
+all: extboot.bin
+
+%.o: %.S
+	$(CC) $(CFLAGS) -o $@ -c $<
+
+extboot.img: extboot.o
+	$(LD) --oformat binary -Ttext 0 -o $@ $<
+
+extboot.bin: extboot.img signrom
+	./signrom extboot.img extboot.bin
+
+signrom: signrom.c
+	$(CC) -o $@ -g -Wall $^
+
+clean:
+	$(RM) *.o *.img *.bin signrom *~
diff --git a/extboot/STATUS b/extboot/STATUS
new file mode 100644
index 0000000..687c6d6
--- /dev/null
+++ b/extboot/STATUS
@@ -0,0 +1,6 @@
+Working
+-------
+
+Ubuntu Server 7.04 (i386)
+Windows 2000 Professional (i386)
+Windows XP SP2 (i386)
diff --git a/extboot/extboot.S b/extboot/extboot.S
new file mode 100644
index 0000000..7b6e9b2
--- /dev/null
+++ b/extboot/extboot.S
@@ -0,0 +1,742 @@
+/*
+ * 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-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
+ */
+
+.code16
+.text
+	.global _start
+_start:
+	.short 0xaa55
+	.byte (_end - _start) / 512
+	push %ax
+	push %bx
+	push %cx
+	push %dx
+	push %ds
+
+	/* setup ds so we can access the IVT */
+	xor %ax, %ax
+	mov %ax, %ds
+
+	/* save old int 19 at int 2b */
+	mov $(0x19 * 4), %bx
+	mov 0(%bx), %ax
+	mov 2(%bx), %cx
+
+	mov $(0x2b * 4), %bx
+	mov %ax, 0(%bx)
+	mov %cx, 2(%bx)
+
+	/* install out int 19 handler */
+	mov $(0x19 * 4), %bx
+	mov $int19_handler, %ax
+	mov %ax, 0(%bx)
+	mov %cs, 2(%bx)
+
+	pop %ds	
+	pop %dx
+	pop %cx
+	pop %bx
+	pop %ax
+	lret
+
+int19_handler:
+	push %ax
+	push %bx
+	push %cx
+	push %dx
+	push %ds
+
+	movw $0x404, %dx
+	inb %dx, %al
+	cmp $1, %al
+	je 1f
+	cmp $2, %al
+	je 2f
+	jmp 3f
+
+1: /* hook int13: intb(0x404) == 1 */
+	/* setup ds to access IVT */
+	xor %ax, %ax
+	mov %ax, %ds
+
+	/* save old int 13 to int 2c */
+	mov $(0x13 * 4), %bx
+	mov 0(%bx), %ax
+	mov 2(%bx), %cx
+
+	mov $(0x2c * 4), %bx
+	mov %ax, 0(%bx)
+	mov %cx, 2(%bx)
+
+	/* install our int 13 handler */
+	mov $(0x13 * 4), %bx
+	mov $int13_handler, %ax
+
+	mov %ax, 0(%bx)
+	mov %cs, 2(%bx)
+	jmp 3f
+	
+2: /* linux boot: intb(0x404) == 2 */
+	cli
+	cld
+	mov $0x9000, %ax
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %fs
+	mov %ax, %gs
+	mov %ax, %ss
+	mov $0x8ffe, %sp
+	ljmp $0x9000 + 0x20, $0
+
+3: /* fall through: inb(0x404) == 0 */
+	pop %ds
+	pop %dx
+	pop %cx
+	pop %bx
+	pop %ax
+	int $0x2b
+
+#define FLAGS_CF	0x01
+	
+.macro clc
+	push %ax
+	pushf
+	pop %ax
+	and $(~FLAGS_CF), %ax
+	push %ax
+	popf
+	pop %ax
+.endm
+
+.macro stc
+	push %ax
+	pushf
+	pop %ax
+	or $(FLAGS_CF), %ax
+	push %ax
+	popf
+	pop %ax
+.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
+	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 $8
+
+	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
+	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 $8
+
+	/* 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
+	ret
+
+alternate_disk_reset:
+	movb $0, %ah
+	clc
+	ret
+
+read_disk_drive_size:
+	push %bx
+	alloca $8
+
+	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
+	ret
+
+check_if_extensions_present:
+	mov $0x30, %ah
+	mov $0xAA55, %bx
+	mov $0x07, %cx
+	clc
+	ret
+
+.macro extended_read_write_sectors cmd
+	cmpb $10, 0(%si)
+	jg 1f
+	mov $1, %ah
+	stc
+	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
+	ret
+.endm
+
+extended_read_sectors:
+	extended_read_write_sectors $0x01
+
+extended_write_sectors:
+	extended_read_write_sectors $0x02
+
+get_extended_drive_parameters:
+	mov $1, %ah
+	stc
+	ret
+#if 0
+	/* this function is seriously borked */
+1:
+	push %ax
+	push %bp
+	push %cx
+	push %dx
+	
+	allocbpa $8
+
+	movw $0, 0(%bp) /* read c,h,s */
+	push %bp
+	call send_command
+	add $2, %sp
+
+	/* check the size of the passed in data */
+	cmpw $26, 0(%si)
+	mov 0(%si), %ax
+	dump %ax
+	jle 0b
+
+	/* 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)
+
+	/* calculate total sectors */
+
+	/* cx:dx = cylinders */
+	mov 2(%bp), %dx
+	xor %cx, %cx
+
+	/* *= heads */
+	push 4(%bp)
+	push $0
+	push %dx
+	push %cx
+	call mul32
+	add $8, %sp
+
+	/* *= sectors */
+	push 6(%bp)
+	push $0
+	push %dx
+	push %cx
+	call mul32
+	add $8, %sp
+
+	/* total number of sectors */
+	mov %dx, 16(%si)
+	mov %cx, 18(%si)
+	xor %ax, %ax
+	mov %ax, 20(%si)
+	mov %ax, 22(%si)
+
+	/* number of bytes per sector */
+	movw $512, 24(%si)
+
+	/* optional segmention:offset to EDD config */
+	cmpw $30, 0(%si)
+	jl 1f
+
+	movw $0xFFFF, 26(%si)
+	movw $0xFFFF, 28(%si)
+	
+1:
+	freebpa
+	
+	pop %dx
+	pop %cx
+	pop %bp
+	pop %ax
+
+	mov $0, %ah
+	clc
+	ret
+#endif
+
+terminate_disk_emulation:
+	mov $1, %ah
+	stc
+	ret
+
+int13_handler:
+	cmp $0x80, %dl
+	je 1f
+	int $0x2c
+	iret
+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/extboot/signrom.c b/extboot/signrom.c
new file mode 100644
index 0000000..fe8d677
--- /dev/null
+++ b/extboot/signrom.c
@@ -0,0 +1,79 @@
+/*
+ * 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-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+int main(int argc, char **argv)
+{
+	FILE *fin, *fout;
+	char buffer[512], oldbuffer[512];
+	int i, size, lag = 0;
+	uint8_t sum = 0;
+
+	if (argc != 3) {
+		printf("Usage: %s ROM OUTPUT\n", argv[0]);
+		return 1;
+	}
+
+	fin = fopen(argv[1], "rb");
+	fout = fopen(argv[2], "wb");
+
+	if (fin == NULL || fout == NULL) {
+		fprintf(stderr, "Could not open input/output files\n");
+		return 1;
+	}
+
+	do {
+		size = fread(buffer, 512, 1, fin);
+		if (size == 1) {
+			for (i = 0; i < 512; i++)
+				sum += buffer[i];
+
+			if (lag) {
+				if (fwrite(oldbuffer, 512, 1, fout) != 1) {
+					fprintf(stderr, "Write failed\n");
+					return 1;
+				}
+			}
+			lag = 1;
+			memcpy(oldbuffer, buffer, 512);
+		}
+	} while (size == 1);
+
+	if (size != 0) {
+		fprintf(stderr, "Failed to read from input file\n");
+		return 1;
+	}
+
+	oldbuffer[511] = -sum;
+
+	if (fwrite(oldbuffer, 512, 1, fout) != 1) {
+		fprintf(stderr, "Failed to write to output file\n");
+		return 1;
+	}
+
+	fclose(fin);
+	fclose(fout);
+
+	return 0;
+}

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2008-01-02 16:22 [PATCH 1/2] Add extboot to kvm-userspace Anthony Liguori
     [not found] ` <119929095077-git-send-email-aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
2008-01-02 16:22   ` [PATCH 2/2] Add QEMU support for extboot Anthony Liguori
     [not found]     ` <11992909511985-git-send-email-aliguori-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
2008-01-03  9:51       ` Avi Kivity
     [not found]         ` <477CB006.2070606-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-01-03 15:12           ` Anthony Liguori

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