Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

12 files changed, 3548 insertions, 0 deletions

diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/apm.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/apm.c
new file mode 100644
index 000000000..3b13e1cd0
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/apm.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2013 Marin Hannache <ipxe@mareo.fr>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * Advanced Power Management
+ *
+ */
+
+#include <errno.h>
+#include <realmode.h>
+#include <ipxe/reboot.h>
+
+/**
+ * Power off the computer using APM
+ *
+ * @ret rc		Return status code
+ */
+static int apm_poweroff ( void ) {
+	uint16_t apm_version;
+	uint16_t apm_signature;
+	uint16_t apm_flags;
+	uint16_t carry;
+
+	/* APM check */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x15\n\t"
+	                                   "adc %%edx,0\n\t" )
+	                       : "=a" ( apm_version ), "=b" ( apm_signature ),
+                                 "=c" ( apm_flags ), "=d" ( carry )
+	                       : "a" ( 0x5300 ), "b" ( 0x0000 ),
+				 "d" ( 0x0000 ) );
+	if ( carry ) {
+		DBG ( "APM not present\n" );
+		return -ENOTSUP;
+	}
+	if ( apm_signature != 0x504d ) { /* signature 'PM' */
+		DBG ( "APM not present\n" );
+		return -ENOTSUP;
+	}
+	if ( apm_version < 0x0101 ) { /* Need version 1.1+ */
+		DBG ( "APM 1.1+ not supported\n" );
+		return -ENOTSUP;
+	}
+	if ( ( apm_flags & 0x8 ) == 0x8 ) {
+		DBG ( "APM power management disabled\n" );
+		return -EPERM;
+	}
+	DBG2 ( "APM check completed\n" );
+
+	/* APM initialisation */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x15\n\t"
+	                                   "adc %%edx,0\n\t" )
+	                       : "=d" ( carry )
+	                       : "a" ( 0x5301 ), "b" ( 0x0000 ),
+	                         "d" ( 0x0000 ) );
+	if ( carry ) {
+		DBG ( "APM initialisation failed\n" );
+		return -EIO;
+	}
+	DBG2 ( "APM initialisation completed\n" );
+
+	/* Set APM driver version */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x15\n\t"
+	                                   "adc %%edx,0\n\t" )
+	                       : "=d" ( carry )
+	                       : "a" ( 0x530e ), "b" ( 0x0000 ),
+	                         "c" ( 0x0101 ), "d" ( 0x0000 ) );
+	if ( carry ) {
+		DBG ( "APM setting driver version failed\n" );
+		return -EIO;
+	}
+	DBG2 ( "APM driver version set\n" );
+
+	/* Setting power state to off */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x15\n\t"
+	                                   "adc %%edx,0\n\t" )
+	                       : "=d" ( carry )
+	                       : "a" ( 0x5307 ), "b" ( 0x0001 ),
+	                         "c" ( 0x0003 ), "d" ( 0x0000) );
+	if ( carry ) {
+		DBG ( "APM setting power state failed\n" );
+		return -ENOTTY;
+	}
+
+	/* Should never happen */
+	return -ECANCELED;
+}
+
+PROVIDE_REBOOT ( pcbios, poweroff, apm_poweroff );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_nap.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_nap.c
new file mode 100644
index 000000000..1e7de756b
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_nap.c
@@ -0,0 +1,16 @@
+#include <ipxe/nap.h>
+#include <realmode.h>
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * Save power by halting the CPU until the next interrupt
+ *
+ */
+static void bios_cpu_nap ( void ) {
+	__asm__ __volatile__ ( "sti\n\t"
+			       "hlt\n\t"
+			       "cli\n\t" );
+}
+
+PROVIDE_NAP ( pcbios, cpu_nap, bios_cpu_nap );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_reboot.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_reboot.c
new file mode 100644
index 000000000..68546b2e5
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_reboot.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Standard PC-BIOS reboot mechanism
+ *
+ */
+
+#include <ipxe/reboot.h>
+#include <realmode.h>
+#include <bios.h>
+
+/**
+ * Reboot system
+ *
+ * @v warm		Perform a warm reboot
+ */
+static void bios_reboot ( int warm ) {
+	uint16_t flag;
+
+	/* Configure BIOS for cold/warm reboot */
+	flag = ( warm ? BDA_REBOOT_WARM : 0 );
+	put_real ( flag, BDA_SEG, BDA_REBOOT );
+
+	/* Jump to system reset vector */
+	__asm__ __volatile__ ( REAL_CODE ( "ljmp $0xf000, $0xfff0" ) : : );
+}
+
+PROVIDE_REBOOT ( pcbios, reboot, bios_reboot );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_smbios.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_smbios.c
new file mode 100644
index 000000000..dd7897e29
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_smbios.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/smbios.h>
+#include <realmode.h>
+#include <pnpbios.h>
+
+/** @file
+ *
+ * System Management BIOS
+ *
+ */
+
+/**
+ * Find SMBIOS
+ *
+ * @v smbios		SMBIOS entry point descriptor structure to fill in
+ * @ret rc		Return status code
+ */
+static int bios_find_smbios ( struct smbios *smbios ) {
+	struct smbios_entry entry;
+	int rc;
+
+	/* Scan through BIOS segment to find SMBIOS entry point */
+	if ( ( rc = find_smbios_entry ( real_to_user ( BIOS_SEG, 0 ), 0x10000,
+					&entry ) ) != 0 )
+		return rc;
+
+	/* Fill in entry point descriptor structure */
+	smbios->address = phys_to_user ( entry.smbios_address );
+	smbios->len = entry.smbios_len;
+	smbios->count = entry.smbios_count;
+	smbios->version = SMBIOS_VERSION ( entry.major, entry.minor );
+
+	return 0;
+}
+
+PROVIDE_SMBIOS ( pcbios, find_smbios, bios_find_smbios );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_timer.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_timer.c
new file mode 100644
index 000000000..65bbf9e01
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/bios_timer.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * BIOS timer
+ *
+ */
+
+#include <ipxe/timer.h>
+#include <realmode.h>
+#include <bios.h>
+
+/**
+ * Get current system time in ticks
+ *
+ * @ret ticks		Current time, in ticks
+ *
+ * Use direct memory access to BIOS variables, longword 0040:006C
+ * (ticks today) and byte 0040:0070 (midnight crossover flag) instead
+ * of calling timeofday BIOS interrupt.
+ */
+static unsigned long bios_currticks ( void ) {
+	static int days = 0;
+	uint32_t ticks;
+	uint8_t midnight;
+
+	/* Re-enable interrupts so that the timer interrupt can occur */
+	__asm__ __volatile__ ( "sti\n\t"
+			       "nop\n\t"
+			       "nop\n\t"
+			       "cli\n\t" );
+
+	get_real ( ticks, BDA_SEG, 0x006c );
+	get_real ( midnight, BDA_SEG, 0x0070 );
+
+	if ( midnight ) {
+		midnight = 0;
+		put_real ( midnight, BDA_SEG, 0x0070 );
+		days += 0x1800b0;
+	}
+
+	return ( days + ticks );
+}
+
+PROVIDE_TIMER_INLINE ( pcbios, udelay );
+PROVIDE_TIMER ( pcbios, currticks, bios_currticks );
+PROVIDE_TIMER_INLINE ( pcbios, ticks_per_sec );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/biosint.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/biosint.c
new file mode 100644
index 000000000..a193defa3
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/biosint.c
@@ -0,0 +1,92 @@
+#include <errno.h>
+#include <realmode.h>
+#include <biosint.h>
+
+/**
+ * @file BIOS interrupts
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * Hook INT vector
+ *
+ * @v interrupt		INT number
+ * @v handler		Offset within .text16 to interrupt handler
+ * @v chain_vector	Vector for chaining to previous handler
+ *
+ * Hooks in an i386 INT handler.  The handler itself must reside
+ * within the .text16 segment.  @c chain_vector will be filled in with
+ * the address of the previously-installed handler for this interrupt;
+ * the handler should probably exit by ljmping via this vector.
+ */
+void hook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
+			   struct segoff *chain_vector ) {
+	struct segoff vector = {
+		.segment = rm_cs,
+		.offset = handler,
+	};
+
+	DBG ( "Hooking INT %#02x to %04x:%04x\n",
+	      interrupt, rm_cs, handler );
+
+	if ( ( chain_vector->segment != 0 ) ||
+	     ( chain_vector->offset != 0 ) ) {
+		/* Already hooked; do nothing */
+		DBG ( "...already hooked\n" );
+		return;
+	}
+
+	copy_from_real ( chain_vector, 0, ( interrupt * 4 ),
+			 sizeof ( *chain_vector ) );
+	DBG ( "...chaining to %04x:%04x\n",
+	      chain_vector->segment, chain_vector->offset );
+	if ( DBG_LOG ) {
+		char code[64];
+		copy_from_real ( code, chain_vector->segment,
+				 chain_vector->offset, sizeof ( code ) );
+		DBG_HDA ( *chain_vector, code, sizeof ( code ) );
+	}
+
+	copy_to_real ( 0, ( interrupt * 4 ), &vector, sizeof ( vector ) );
+	hooked_bios_interrupts++;
+}
+
+/**
+ * Unhook INT vector
+ *
+ * @v interrupt		INT number
+ * @v handler		Offset within .text16 to interrupt handler
+ * @v chain_vector	Vector containing address of previous handler
+ *
+ * Unhooks an i386 interrupt handler hooked by hook_i386_vector().
+ * Note that this operation may fail, if some external code has hooked
+ * the vector since we hooked in our handler.  If it fails, it means
+ * that it is not possible to unhook our handler, and we must leave it
+ * (and its chaining vector) resident in memory.
+ */
+int unhook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
+			    struct segoff *chain_vector ) {
+	struct segoff vector;
+
+	DBG ( "Unhooking INT %#02x from %04x:%04x\n",
+	      interrupt, rm_cs, handler );
+
+	copy_from_real ( &vector, 0, ( interrupt * 4 ), sizeof ( vector ) );
+	if ( ( vector.segment != rm_cs ) || ( vector.offset != handler ) ) {
+		DBG ( "...cannot unhook; vector points to %04x:%04x\n",
+		      vector.segment, vector.offset );
+		return -EBUSY;
+	}
+
+	DBG ( "...restoring to %04x:%04x\n",
+	      chain_vector->segment, chain_vector->offset );
+	copy_to_real ( 0, ( interrupt * 4 ), chain_vector,
+		       sizeof ( *chain_vector ) );
+
+	chain_vector->segment = 0;
+	chain_vector->offset = 0;
+	hooked_bios_interrupts--;
+	return 0;
+}
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/int13.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/int13.c
new file mode 100644
index 000000000..1c7a8128f
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/int13.c
@@ -0,0 +1,1989 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <byteswap.h>
+#include <errno.h>
+#include <assert.h>
+#include <ipxe/list.h>
+#include <ipxe/blockdev.h>
+#include <ipxe/io.h>
+#include <ipxe/open.h>
+#include <ipxe/uri.h>
+#include <ipxe/process.h>
+#include <ipxe/xfer.h>
+#include <ipxe/retry.h>
+#include <ipxe/timer.h>
+#include <ipxe/acpi.h>
+#include <ipxe/sanboot.h>
+#include <ipxe/device.h>
+#include <ipxe/pci.h>
+#include <ipxe/iso9660.h>
+#include <ipxe/eltorito.h>
+#include <realmode.h>
+#include <bios.h>
+#include <biosint.h>
+#include <bootsector.h>
+#include <int13.h>
+
+/** @file
+ *
+ * INT 13 emulation
+ *
+ * This module provides a mechanism for exporting block devices via
+ * the BIOS INT 13 disk interrupt interface.  
+ *
+ */
+
+/**
+ * Overall timeout for INT 13 commands (independent of underlying device
+ *
+ * Underlying devices should ideally never become totally stuck.
+ * However, if they do, then the INT 13 mechanism provides no means
+ * for the caller to cancel the operation, and the machine appears to
+ * hang.  Use an overall timeout for all commands to avoid this
+ * problem and bounce timeout failures to the caller.
+ */
+#define INT13_COMMAND_TIMEOUT ( 15 * TICKS_PER_SEC )
+
+/** An INT 13 emulated drive */
+struct int13_drive {
+	/** Reference count */
+	struct refcnt refcnt;
+	/** List of all registered drives */
+	struct list_head list;
+
+	/** Block device URI */
+	struct uri *uri;
+	/** Underlying block device interface */
+	struct interface block;
+
+	/** BIOS in-use drive number (0x00-0xff) */
+	unsigned int drive;
+	/** BIOS natural drive number (0x00-0xff)
+	 *
+	 * This is the drive number that would have been assigned by
+	 * 'naturally' appending the drive to the end of the BIOS
+	 * drive list.
+	 *
+	 * If the emulated drive replaces a preexisting drive, this is
+	 * the drive number that the preexisting drive gets remapped
+	 * to.
+	 */
+	unsigned int natural_drive;
+
+	/** Block device capacity */
+	struct block_device_capacity capacity;
+	/** INT 13 emulated blocksize shift
+	 *
+	 * To allow for emulation of CD-ROM access, this represents
+	 * the left-shift required to translate from INT 13 blocks to
+	 * underlying blocks.
+	 */
+	unsigned int blksize_shift;
+
+	/** Number of cylinders
+	 *
+	 * The cylinder number field in an INT 13 call is ten bits
+	 * wide, giving a maximum of 1024 cylinders.  Conventionally,
+	 * when the 7.8GB limit of a CHS address is exceeded, it is
+	 * the number of cylinders that is increased beyond the
+	 * addressable limit.
+	 */
+	unsigned int cylinders;
+	/** Number of heads
+	 *
+	 * The head number field in an INT 13 call is eight bits wide,
+	 * giving a maximum of 256 heads.  However, apparently all
+	 * versions of MS-DOS up to and including Win95 fail with 256
+	 * heads, so the maximum encountered in practice is 255.
+	 */
+	unsigned int heads;
+	/** Number of sectors per track
+	 *
+	 * The sector number field in an INT 13 call is six bits wide,
+	 * giving a maximum of 63 sectors, since sector numbering
+	 * (unlike head and cylinder numbering) starts at 1, not 0.
+	 */
+	unsigned int sectors_per_track;
+
+	/** Drive is a CD-ROM */
+	int is_cdrom;
+	/** Address of El Torito boot catalog (if any) */
+	unsigned int boot_catalog;
+
+	/** Underlying device status, if in error */
+	int block_rc;
+	/** Status of last operation */
+	int last_status;
+};
+
+/** Vector for chaining to other INT 13 handlers */
+static struct segoff __text16 ( int13_vector );
+#define int13_vector __use_text16 ( int13_vector )
+
+/** Assembly wrapper */
+extern void int13_wrapper ( void );
+
+/** Dummy floppy disk parameter table */
+static struct int13_fdd_parameters __data16 ( int13_fdd_params ) = {
+	/* 512 bytes per sector */
+	.bytes_per_sector = 0x02,
+	/* Highest sectors per track that we ever return */
+	.sectors_per_track = 48,
+};
+#define int13_fdd_params __use_data16 ( int13_fdd_params )
+
+/** List of registered emulated drives */
+static LIST_HEAD ( int13s );
+
+/**
+ * Equipment word
+ *
+ * This is a cached copy of the BIOS Data Area equipment word at
+ * 40:10.
+ */
+static uint16_t equipment_word;
+
+/**
+ * Number of BIOS floppy disk drives
+ *
+ * This is derived from the equipment word.  It is held in .text16 to
+ * allow for easy access by the INT 13,08 wrapper.
+ */
+static uint8_t __text16 ( num_fdds );
+#define num_fdds __use_text16 ( num_fdds )
+
+/**
+ * Number of BIOS hard disk drives
+ *
+ * This is a cached copy of the BIOS Data Area number of hard disk
+ * drives at 40:75.  It is held in .text16 to allow for easy access by
+ * the INT 13,08 wrapper.
+ */
+static uint8_t __text16 ( num_drives );
+#define num_drives __use_text16 ( num_drives )
+
+/**
+ * Calculate INT 13 drive sector size
+ *
+ * @v int13		Emulated drive
+ * @ret blksize		Sector size
+ */
+static inline size_t int13_blksize ( struct int13_drive *int13 ) {
+	return ( int13->capacity.blksize << int13->blksize_shift );
+}
+
+/**
+ * Calculate INT 13 drive capacity
+ *
+ * @v int13		Emulated drive
+ * @ret blocks		Number of blocks
+ */
+static inline uint64_t int13_capacity ( struct int13_drive *int13 ) {
+	return ( int13->capacity.blocks >> int13->blksize_shift );
+}
+
+/**
+ * Calculate INT 13 drive capacity (limited to 32 bits)
+ *
+ * @v int13		Emulated drive
+ * @ret blocks		Number of blocks
+ */
+static inline uint32_t int13_capacity32 ( struct int13_drive *int13 ) {
+	uint64_t capacity = int13_capacity ( int13 );
+	return ( ( capacity <= 0xffffffffUL ) ? capacity : 0xffffffff );
+}
+
+/**
+ * Test if INT 13 drive is a floppy disk drive
+ *
+ * @v int13		Emulated drive
+ * @ret is_fdd		Emulated drive is a floppy disk
+ */
+static inline int int13_is_fdd ( struct int13_drive *int13 ) {
+	return ( ! ( int13->drive & 0x80 ) );
+}
+
+/** An INT 13 command */
+struct int13_command {
+	/** Status */
+	int rc;
+	/** INT 13 drive */
+	struct int13_drive *int13;
+	/** Underlying block device interface */
+	struct interface block;
+	/** Command timeout timer */
+	struct retry_timer timer;
+};
+
+/**
+ * Record INT 13 drive capacity
+ *
+ * @v command		INT 13 command
+ * @v capacity		Block device capacity
+ */
+static void int13_command_capacity ( struct int13_command *command,
+				     struct block_device_capacity *capacity ) {
+	memcpy ( &command->int13->capacity, capacity,
+		 sizeof ( command->int13->capacity ) );
+}
+
+/**
+ * Close INT 13 command
+ *
+ * @v command		INT 13 command
+ * @v rc		Reason for close
+ */
+static void int13_command_close ( struct int13_command *command, int rc ) {
+	intf_restart ( &command->block, rc );
+	stop_timer ( &command->timer );
+	command->rc = rc;
+}
+
+/**
+ * Handle INT 13 command timer expiry
+ *
+ * @v timer		Timer
+ */
+static void int13_command_expired ( struct retry_timer *timer,
+				    int over __unused ) {
+	struct int13_command *command =
+		container_of ( timer, struct int13_command, timer );
+
+	int13_command_close ( command, -ETIMEDOUT );
+}
+
+/** INT 13 command interface operations */
+static struct interface_operation int13_command_op[] = {
+	INTF_OP ( intf_close, struct int13_command *, int13_command_close ),
+	INTF_OP ( block_capacity, struct int13_command *,
+		  int13_command_capacity ),
+};
+
+/** INT 13 command interface descriptor */
+static struct interface_descriptor int13_command_desc =
+	INTF_DESC ( struct int13_command, block, int13_command_op );
+
+/**
+ * Open (or reopen) INT 13 emulated drive underlying block device
+ *
+ * @v int13		Emulated drive
+ * @ret rc		Return status code
+ */
+static int int13_reopen_block ( struct int13_drive *int13 ) {
+	int rc;
+
+	/* Close any existing block device */
+	intf_restart ( &int13->block, -ECONNRESET );
+
+	/* Open block device */
+	if ( ( rc = xfer_open_uri ( &int13->block, int13->uri ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not reopen block "
+		       "device: %s\n", int13->drive, strerror ( rc ) );
+		int13->block_rc = rc;
+		return rc;
+	}
+
+	/* Clear block device error status */
+	int13->block_rc = 0;
+
+	return 0;
+}
+
+/**
+ * Prepare to issue INT 13 command
+ *
+ * @v command		INT 13 command
+ * @v int13		Emulated drive
+ * @ret rc		Return status code
+ */
+static int int13_command_start ( struct int13_command *command,
+				 struct int13_drive *int13 ) {
+	int rc;
+
+	/* Sanity check */
+	assert ( command->int13 == NULL );
+	assert ( ! timer_running ( &command->timer ) );
+
+	/* Reopen block device if necessary */
+	if ( ( int13->block_rc != 0 ) &&
+	     ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+		return rc;
+
+	/* Initialise command */
+	command->rc = -EINPROGRESS;
+	command->int13 = int13;
+	start_timer_fixed ( &command->timer, INT13_COMMAND_TIMEOUT );
+
+	/* Wait for block control interface to become ready */
+	while ( ( command->rc == -EINPROGRESS ) &&
+		( xfer_window ( &int13->block ) == 0 ) ) {
+		step();
+	}
+
+	return ( ( command->rc == -EINPROGRESS ) ?
+		 int13->block_rc : command->rc );
+}
+
+/**
+ * Wait for INT 13 command to complete
+ *
+ * @v command		INT 13 command
+ * @ret rc		Return status code
+ */
+static int int13_command_wait ( struct int13_command *command ) {
+
+	/* Sanity check */
+	assert ( timer_running ( &command->timer ) );
+
+	/* Wait for command to complete */
+	while ( command->rc == -EINPROGRESS )
+		step();
+
+	assert ( ! timer_running ( &command->timer ) );
+	return command->rc;
+}
+
+/**
+ * Terminate INT 13 command
+ *
+ * @v command		INT 13 command
+ */
+static void int13_command_stop ( struct int13_command *command ) {
+	stop_timer ( &command->timer );
+	command->int13 = NULL;
+}
+
+/** The single active INT 13 command */
+static struct int13_command int13_command = {
+	.block = INTF_INIT ( int13_command_desc ),
+	.timer = TIMER_INIT ( int13_command_expired ),
+};
+
+/**
+ * Read from or write to INT 13 drive
+ *
+ * @v int13		Emulated drive
+ * @v lba		Starting logical block address
+ * @v count		Number of logical blocks
+ * @v buffer		Data buffer
+ * @v block_rw		Block read/write method
+ * @ret rc		Return status code
+ */
+static int int13_rw ( struct int13_drive *int13, uint64_t lba,
+		      unsigned int count, userptr_t buffer,
+		      int ( * block_rw ) ( struct interface *control,
+					   struct interface *data,
+					   uint64_t lba, unsigned int count,
+					   userptr_t buffer, size_t len ) ) {
+	struct int13_command *command = &int13_command;
+	unsigned int frag_count;
+	size_t frag_len;
+	int rc;
+
+	/* Translate to underlying blocksize */
+	lba <<= int13->blksize_shift;
+	count <<= int13->blksize_shift;
+
+	while ( count ) {
+
+		/* Determine fragment length */
+		frag_count = count;
+		if ( frag_count > int13->capacity.max_count )
+			frag_count = int13->capacity.max_count;
+		frag_len = ( int13->capacity.blksize * frag_count );
+
+		/* Issue command */
+		if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) ||
+		     ( ( rc = block_rw ( &int13->block, &command->block, lba,
+					 frag_count, buffer,
+					 frag_len ) ) != 0 ) ||
+		     ( ( rc = int13_command_wait ( command ) ) != 0 ) ) {
+			int13_command_stop ( command );
+			return rc;
+		}
+		int13_command_stop ( command );
+
+		/* Move to next fragment */
+		lba += frag_count;
+		count -= frag_count;
+		buffer = userptr_add ( buffer, frag_len );
+	}
+
+	return 0;
+}
+
+/**
+ * Read INT 13 drive capacity
+ *
+ * @v int13		Emulated drive
+ * @ret rc		Return status code
+ */
+static int int13_read_capacity ( struct int13_drive *int13 ) {
+	struct int13_command *command = &int13_command;
+	int rc;
+
+	/* Issue command */
+	if ( ( ( rc = int13_command_start ( command, int13 ) ) != 0 ) ||
+	     ( ( rc = block_read_capacity ( &int13->block,
+					    &command->block ) ) != 0 ) ||
+	     ( ( rc = int13_command_wait ( command ) ) != 0 ) ) {
+		int13_command_stop ( command );
+		return rc;
+	}
+
+	int13_command_stop ( command );
+	return 0;
+}
+
+/**
+ * Parse ISO9660 parameters
+ *
+ * @v int13		Emulated drive
+ * @v scratch		Scratch area for single-sector reads
+ * @ret rc		Return status code
+ *
+ * Reads and parses ISO9660 parameters, if present.
+ */
+static int int13_parse_iso9660 ( struct int13_drive *int13, void *scratch ) {
+	static const struct iso9660_primary_descriptor_fixed primary_check = {
+		.type = ISO9660_TYPE_PRIMARY,
+		.id = ISO9660_ID,
+	};
+	struct iso9660_primary_descriptor *primary = scratch;
+	static const struct eltorito_descriptor_fixed boot_check = {
+		.type = ISO9660_TYPE_BOOT,
+		.id = ISO9660_ID,
+		.version = 1,
+		.system_id = "EL TORITO SPECIFICATION",
+	};
+	struct eltorito_descriptor *boot = scratch;
+	unsigned int blksize;
+	unsigned int blksize_shift;
+	int rc;
+
+	/* Calculate required blocksize shift */
+	blksize = int13_blksize ( int13 );
+	blksize_shift = 0;
+	while ( blksize < ISO9660_BLKSIZE ) {
+		blksize <<= 1;
+		blksize_shift++;
+	}
+	if ( blksize > ISO9660_BLKSIZE ) {
+		/* Do nothing if the blksize is invalid for CD-ROM access */
+		return 0;
+	}
+
+	/* Read primary volume descriptor */
+	if ( ( rc = int13_rw ( int13,
+			       ( ISO9660_PRIMARY_LBA << blksize_shift ), 1,
+			       virt_to_user ( primary ), block_read ) ) != 0 ){
+		DBGC ( int13, "INT13 drive %02x could not read ISO9660 "
+		       "primary volume descriptor: %s\n",
+		       int13->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Do nothing unless this is an ISO image */
+	if ( memcmp ( primary, &primary_check, sizeof ( primary_check ) ) != 0 )
+		return 0;
+	DBGC ( int13, "INT13 drive %02x contains an ISO9660 filesystem; "
+	       "treating as CD-ROM\n", int13->drive );
+	int13->is_cdrom = 1;
+
+	/* Read boot record volume descriptor */
+	if ( ( rc = int13_rw ( int13,
+			       ( ELTORITO_LBA << blksize_shift ), 1,
+			       virt_to_user ( boot ), block_read ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not read El Torito boot "
+		       "record volume descriptor: %s\n",
+		       int13->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Check for an El Torito boot catalog */
+	if ( memcmp ( boot, &boot_check, sizeof ( boot_check ) ) == 0 ) {
+		int13->boot_catalog = boot->sector;
+		DBGC ( int13, "INT13 drive %02x has an El Torito boot catalog "
+		       "at LBA %08x\n", int13->drive, int13->boot_catalog );
+	} else {
+		DBGC ( int13, "INT13 drive %02x has no El Torito boot "
+		       "catalog\n", int13->drive );
+	}
+
+	/* Configure drive for no-emulation CD-ROM access */
+	int13->blksize_shift += blksize_shift;
+
+	return 0;
+}
+
+/**
+ * Guess INT 13 hard disk drive geometry
+ *
+ * @v int13		Emulated drive
+ * @v scratch		Scratch area for single-sector reads
+ * @ret heads		Guessed number of heads
+ * @ret sectors		Guessed number of sectors per track
+ * @ret rc		Return status code
+ *
+ * Guesses the drive geometry by inspecting the partition table.
+ */
+static int int13_guess_geometry_hdd ( struct int13_drive *int13, void *scratch,
+				      unsigned int *heads,
+				      unsigned int *sectors ) {
+	struct master_boot_record *mbr = scratch;
+	struct partition_table_entry *partition;
+	unsigned int i;
+	int rc;
+
+	/* Default guess is xx/255/63 */
+	*heads = 255;
+	*sectors = 63;
+
+	/* Read partition table */
+	if ( ( rc = int13_rw ( int13, 0, 1, virt_to_user ( mbr ),
+			       block_read ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not read "
+		       "partition table to guess geometry: %s\n",
+		       int13->drive, strerror ( rc ) );
+		return rc;
+	}
+	DBGC2 ( int13, "INT13 drive %02x has MBR:\n", int13->drive );
+	DBGC2_HDA ( int13, 0, mbr, sizeof ( *mbr ) );
+	DBGC ( int13, "INT13 drive %02x has signature %08x\n",
+	       int13->drive, mbr->signature );
+
+	/* Scan through partition table and modify guesses for
+	 * heads and sectors_per_track if we find any used
+	 * partitions.
+	 */
+	for ( i = 0 ; i < 4 ; i++ ) {
+		partition = &mbr->partitions[i];
+		if ( ! partition->type )
+			continue;
+		*heads = ( PART_HEAD ( partition->chs_end ) + 1 );
+		*sectors = PART_SECTOR ( partition->chs_end );
+		DBGC ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based "
+		       "on partition %d\n",
+		       int13->drive, *heads, *sectors, ( i + 1 ) );
+	}
+
+	return 0;
+}
+
+/** Recognised floppy disk geometries */
+static const struct int13_fdd_geometry int13_fdd_geometries[] = {
+	INT13_FDD_GEOMETRY ( 40, 1, 8 ),
+	INT13_FDD_GEOMETRY ( 40, 1, 9 ),
+	INT13_FDD_GEOMETRY ( 40, 2, 8 ),
+	INT13_FDD_GEOMETRY ( 40, 1, 9 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 8 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 9 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 15 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 18 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 20 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 21 ),
+	INT13_FDD_GEOMETRY ( 82, 2, 21 ),
+	INT13_FDD_GEOMETRY ( 83, 2, 21 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 22 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 23 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 24 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 36 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 39 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 40 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 44 ),
+	INT13_FDD_GEOMETRY ( 80, 2, 48 ),
+};
+
+/**
+ * Guess INT 13 floppy disk drive geometry
+ *
+ * @v int13		Emulated drive
+ * @ret heads		Guessed number of heads
+ * @ret sectors		Guessed number of sectors per track
+ * @ret rc		Return status code
+ *
+ * Guesses the drive geometry by inspecting the disk size.
+ */
+static int int13_guess_geometry_fdd ( struct int13_drive *int13,
+				      unsigned int *heads,
+				      unsigned int *sectors ) {
+	unsigned int blocks = int13_capacity ( int13 );
+	const struct int13_fdd_geometry *geometry;
+	unsigned int cylinders;
+	unsigned int i;
+
+	/* Look for a match against a known geometry */
+	for ( i = 0 ; i < ( sizeof ( int13_fdd_geometries ) /
+			    sizeof ( int13_fdd_geometries[0] ) ) ; i++ ) {
+		geometry = &int13_fdd_geometries[i];
+		cylinders = INT13_FDD_CYLINDERS ( geometry );
+		*heads = INT13_FDD_HEADS ( geometry );
+		*sectors = INT13_FDD_SECTORS ( geometry );
+		if ( ( cylinders * (*heads) * (*sectors) ) == blocks ) {
+			DBGC ( int13, "INT13 drive %02x guessing C/H/S "
+			       "%d/%d/%d based on size %dK\n", int13->drive,
+			       cylinders, *heads, *sectors, ( blocks / 2 ) );
+			return 0;
+		}
+	}
+
+	/* Otherwise, assume a partial disk image in the most common
+	 * format (1440K, 80/2/18).
+	 */
+	*heads = 2;
+	*sectors = 18;
+	DBGC ( int13, "INT13 drive %02x guessing C/H/S xx/%d/%d based on size "
+	       "%dK\n", int13->drive, *heads, *sectors, ( blocks / 2 ) );
+	return 0;
+}
+
+/**
+ * Guess INT 13 drive geometry
+ *
+ * @v int13		Emulated drive
+ * @v scratch		Scratch area for single-sector reads
+ * @ret rc		Return status code
+ */
+static int int13_guess_geometry ( struct int13_drive *int13, void *scratch ) {
+	unsigned int guessed_heads;
+	unsigned int guessed_sectors;
+	unsigned int blocks;
+	unsigned int blocks_per_cyl;
+	int rc;
+
+	/* Don't even try when the blksize is invalid for C/H/S access */
+	if ( int13_blksize ( int13 ) != INT13_BLKSIZE )
+		return 0;
+
+	/* Guess geometry according to drive type */
+	if ( int13_is_fdd ( int13 ) ) {
+		if ( ( rc = int13_guess_geometry_fdd ( int13, &guessed_heads,
+						       &guessed_sectors )) != 0)
+			return rc;
+	} else {
+		if ( ( rc = int13_guess_geometry_hdd ( int13, scratch,
+						       &guessed_heads,
+						       &guessed_sectors )) != 0)
+			return rc;
+	}
+
+	/* Apply guesses if no geometry already specified */
+	if ( ! int13->heads )
+		int13->heads = guessed_heads;
+	if ( ! int13->sectors_per_track )
+		int13->sectors_per_track = guessed_sectors;
+	if ( ! int13->cylinders ) {
+		/* Avoid attempting a 64-bit divide on a 32-bit system */
+		blocks = int13_capacity32 ( int13 );
+		blocks_per_cyl = ( int13->heads * int13->sectors_per_track );
+		assert ( blocks_per_cyl != 0 );
+		int13->cylinders = ( blocks / blocks_per_cyl );
+		if ( int13->cylinders > 1024 )
+			int13->cylinders = 1024;
+	}
+
+	return 0;
+}
+
+/**
+ * Update BIOS drive count
+ */
+static void int13_sync_num_drives ( void ) {
+	struct int13_drive *int13;
+	uint8_t *counter;
+	uint8_t max_drive;
+	uint8_t required;
+
+	/* Get current drive counts */
+	get_real ( equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
+	get_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
+	num_fdds = ( ( equipment_word & 0x0001 ) ?
+		     ( ( ( equipment_word >> 6 ) & 0x3 ) + 1 ) : 0 );
+
+	/* Ensure count is large enough to cover all of our emulated drives */
+	list_for_each_entry ( int13, &int13s, list ) {
+		counter = ( int13_is_fdd ( int13 ) ? &num_fdds : &num_drives );
+		max_drive = int13->drive;
+		if ( max_drive < int13->natural_drive )
+			max_drive = int13->natural_drive;
+		required = ( ( max_drive & 0x7f ) + 1 );
+		if ( *counter < required ) {
+			*counter = required;
+			DBGC ( int13, "INT13 drive %02x added to drive count: "
+			       "%d HDDs, %d FDDs\n",
+			       int13->drive, num_drives, num_fdds );
+		}
+	}
+
+	/* Update current drive count */
+	equipment_word &= ~( ( 0x3 << 6 ) | 0x0001 );
+	if ( num_fdds ) {
+		equipment_word |= ( 0x0001 |
+				    ( ( ( num_fdds - 1 ) & 0x3 ) << 6 ) );
+	}
+	put_real ( equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
+	put_real ( num_drives, BDA_SEG, BDA_NUM_DRIVES );
+}
+
+/**
+ * Check number of drives
+ */
+static void int13_check_num_drives ( void ) {
+	uint16_t check_equipment_word;
+	uint8_t check_num_drives;
+
+	get_real ( check_equipment_word, BDA_SEG, BDA_EQUIPMENT_WORD );
+	get_real ( check_num_drives, BDA_SEG, BDA_NUM_DRIVES );
+	if ( ( check_equipment_word != equipment_word ) ||
+	     ( check_num_drives != num_drives ) ) {
+		int13_sync_num_drives();
+	}
+}
+
+/**
+ * INT 13, 00 - Reset disk system
+ *
+ * @v int13		Emulated drive
+ * @ret status		Status code
+ */
+static int int13_reset ( struct int13_drive *int13,
+			 struct i386_all_regs *ix86 __unused ) {
+	int rc;
+
+	DBGC2 ( int13, "Reset drive\n" );
+
+	/* Reopen underlying block device */
+	if ( ( rc = int13_reopen_block ( int13 ) ) != 0 )
+		return -INT13_STATUS_RESET_FAILED;
+
+	/* Check that block device is functional */
+	if ( ( rc = int13_read_capacity ( int13 ) ) != 0 )
+		return -INT13_STATUS_RESET_FAILED;
+
+	return 0;
+}
+
+/**
+ * INT 13, 01 - Get status of last operation
+ *
+ * @v int13		Emulated drive
+ * @ret status		Status code
+ */
+static int int13_get_last_status ( struct int13_drive *int13,
+				   struct i386_all_regs *ix86 __unused ) {
+	DBGC2 ( int13, "Get status of last operation\n" );
+	return int13->last_status;
+}
+
+/**
+ * Read / write sectors
+ *
+ * @v int13		Emulated drive
+ * @v al		Number of sectors to read or write (must be nonzero)
+ * @v ch		Low bits of cylinder number
+ * @v cl (bits 7:6)	High bits of cylinder number
+ * @v cl (bits 5:0)	Sector number
+ * @v dh		Head number
+ * @v es:bx		Data buffer
+ * @v block_rw		Block read/write method
+ * @ret status		Status code
+ * @ret al		Number of sectors read or written
+ */
+static int int13_rw_sectors ( struct int13_drive *int13,
+			      struct i386_all_regs *ix86,
+			      int ( * block_rw ) ( struct interface *control,
+						   struct interface *data,
+						   uint64_t lba,
+						   unsigned int count,
+						   userptr_t buffer,
+						   size_t len ) ) {
+	unsigned int cylinder, head, sector;
+	unsigned long lba;
+	unsigned int count;
+	userptr_t buffer;
+	int rc;
+
+	/* Validate blocksize */
+	if ( int13_blksize ( int13 ) != INT13_BLKSIZE ) {
+		DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) "
+		       "for non-extended read/write\n",
+		       int13->drive, int13_blksize ( int13 ) );
+		return -INT13_STATUS_INVALID;
+	}
+
+	/* Calculate parameters */
+	cylinder = ( ( ( ix86->regs.cl & 0xc0 ) << 2 ) | ix86->regs.ch );
+	head = ix86->regs.dh;
+	sector = ( ix86->regs.cl & 0x3f );
+	if ( ( cylinder >= int13->cylinders ) ||
+	     ( head >= int13->heads ) ||
+	     ( sector < 1 ) || ( sector > int13->sectors_per_track ) ) {
+		DBGC ( int13, "C/H/S %d/%d/%d out of range for geometry "
+		       "%d/%d/%d\n", cylinder, head, sector, int13->cylinders,
+		       int13->heads, int13->sectors_per_track );
+		return -INT13_STATUS_INVALID;
+	}
+	lba = ( ( ( ( cylinder * int13->heads ) + head )
+		  * int13->sectors_per_track ) + sector - 1 );
+	count = ix86->regs.al;
+	buffer = real_to_user ( ix86->segs.es, ix86->regs.bx );
+
+	DBGC2 ( int13, "C/H/S %d/%d/%d = LBA %08lx <-> %04x:%04x (count %d)\n",
+		cylinder, head, sector, lba, ix86->segs.es, ix86->regs.bx,
+		count );
+
+	/* Read from / write to block device */
+	if ( ( rc = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x I/O failed: %s\n",
+		       int13->drive, strerror ( rc ) );
+		return -INT13_STATUS_READ_ERROR;
+	}
+
+	return 0;
+}
+
+/**
+ * INT 13, 02 - Read sectors
+ *
+ * @v int13		Emulated drive
+ * @v al		Number of sectors to read (must be nonzero)
+ * @v ch		Low bits of cylinder number
+ * @v cl (bits 7:6)	High bits of cylinder number
+ * @v cl (bits 5:0)	Sector number
+ * @v dh		Head number
+ * @v es:bx		Data buffer
+ * @ret status		Status code
+ * @ret al		Number of sectors read
+ */
+static int int13_read_sectors ( struct int13_drive *int13,
+				struct i386_all_regs *ix86 ) {
+	DBGC2 ( int13, "Read: " );
+	return int13_rw_sectors ( int13, ix86, block_read );
+}
+
+/**
+ * INT 13, 03 - Write sectors
+ *
+ * @v int13		Emulated drive
+ * @v al		Number of sectors to write (must be nonzero)
+ * @v ch		Low bits of cylinder number
+ * @v cl (bits 7:6)	High bits of cylinder number
+ * @v cl (bits 5:0)	Sector number
+ * @v dh		Head number
+ * @v es:bx		Data buffer
+ * @ret status		Status code
+ * @ret al		Number of sectors written
+ */
+static int int13_write_sectors ( struct int13_drive *int13,
+				 struct i386_all_regs *ix86 ) {
+	DBGC2 ( int13, "Write: " );
+	return int13_rw_sectors ( int13, ix86, block_write );
+}
+
+/**
+ * INT 13, 08 - Get drive parameters
+ *
+ * @v int13		Emulated drive
+ * @ret status		Status code
+ * @ret ch		Low bits of maximum cylinder number
+ * @ret cl (bits 7:6)	High bits of maximum cylinder number
+ * @ret cl (bits 5:0)	Maximum sector number
+ * @ret dh		Maximum head number
+ * @ret dl		Number of drives
+ */
+static int int13_get_parameters ( struct int13_drive *int13,
+				  struct i386_all_regs *ix86 ) {
+	unsigned int max_cylinder = int13->cylinders - 1;
+	unsigned int max_head = int13->heads - 1;
+	unsigned int max_sector = int13->sectors_per_track; /* sic */
+
+	DBGC2 ( int13, "Get drive parameters\n" );
+
+	/* Validate blocksize */
+	if ( int13_blksize ( int13 ) != INT13_BLKSIZE ) {
+		DBGC ( int13, "\nINT 13 drive %02x invalid blocksize (%zd) "
+		       "for non-extended parameters\n",
+		       int13->drive, int13_blksize ( int13 ) );
+		return -INT13_STATUS_INVALID;
+	}
+
+	/* Common parameters */
+	ix86->regs.ch = ( max_cylinder & 0xff );
+	ix86->regs.cl = ( ( ( max_cylinder >> 8 ) << 6 ) | max_sector );
+	ix86->regs.dh = max_head;
+	ix86->regs.dl = ( int13_is_fdd ( int13 ) ? num_fdds : num_drives );
+
+	/* Floppy-specific parameters */
+	if ( int13_is_fdd ( int13 ) ) {
+		ix86->regs.bl = INT13_FDD_TYPE_1M44;
+		ix86->segs.es = rm_ds;
+		ix86->regs.di = __from_data16 ( &int13_fdd_params );
+	}
+
+	return 0;
+}
+
+/**
+ * INT 13, 15 - Get disk type
+ *
+ * @v int13		Emulated drive
+ * @ret ah		Type code
+ * @ret cx:dx		Sector count
+ * @ret status		Status code / disk type
+ */
+static int int13_get_disk_type ( struct int13_drive *int13,
+				 struct i386_all_regs *ix86 ) {
+	uint32_t blocks;
+
+	DBGC2 ( int13, "Get disk type\n" );
+
+	if ( int13_is_fdd ( int13 ) ) {
+		return INT13_DISK_TYPE_FDD;
+	} else {
+		blocks = int13_capacity32 ( int13 );
+		ix86->regs.cx = ( blocks >> 16 );
+		ix86->regs.dx = ( blocks & 0xffff );
+		return INT13_DISK_TYPE_HDD;
+	}
+}
+
+/**
+ * INT 13, 41 - Extensions installation check
+ *
+ * @v int13		Emulated drive
+ * @v bx		0x55aa
+ * @ret bx		0xaa55
+ * @ret cx		Extensions API support bitmap
+ * @ret status		Status code / API version
+ */
+static int int13_extension_check ( struct int13_drive *int13 __unused,
+				   struct i386_all_regs *ix86 ) {
+	if ( ix86->regs.bx == 0x55aa ) {
+		DBGC2 ( int13, "INT13 extensions installation check\n" );
+		ix86->regs.bx = 0xaa55;
+		ix86->regs.cx = ( INT13_EXTENSION_LINEAR |
+				  INT13_EXTENSION_EDD |
+				  INT13_EXTENSION_64BIT );
+		return INT13_EXTENSION_VER_3_0;
+	} else {
+		return -INT13_STATUS_INVALID;
+	}
+}
+
+/**
+ * Extended read / write
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @v block_rw		Block read/write method
+ * @ret status		Status code
+ */
+static int int13_extended_rw ( struct int13_drive *int13,
+			       struct i386_all_regs *ix86,
+			       int ( * block_rw ) ( struct interface *control,
+						    struct interface *data,
+						    uint64_t lba,
+						    unsigned int count,
+						    userptr_t buffer,
+						    size_t len ) ) {
+	struct int13_disk_address addr;
+	uint8_t bufsize;
+	uint64_t lba;
+	unsigned long count;
+	userptr_t buffer;
+	int rc;
+
+	/* Extended reads are not allowed on floppy drives.
+	 * ELTORITO.SYS seems to assume that we are really a CD-ROM if
+	 * we support extended reads for a floppy drive.
+	 */
+	if ( int13_is_fdd ( int13 ) )
+		return -INT13_STATUS_INVALID;
+
+	/* Get buffer size */
+	get_real ( bufsize, ix86->segs.ds,
+		   ( ix86->regs.si + offsetof ( typeof ( addr ), bufsize ) ) );
+	if ( bufsize < offsetof ( typeof ( addr ), buffer_phys ) ) {
+		DBGC2 ( int13, "<invalid buffer size %#02x\n>\n", bufsize );
+		return -INT13_STATUS_INVALID;
+	}
+
+	/* Read parameters from disk address structure */
+	memset ( &addr, 0, sizeof ( addr ) );
+	copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si, bufsize );
+	lba = addr.lba;
+	DBGC2 ( int13, "LBA %08llx <-> ", ( ( unsigned long long ) lba ) );
+	if ( ( addr.count == 0xff ) ||
+	     ( ( addr.buffer.segment == 0xffff ) &&
+	       ( addr.buffer.offset == 0xffff ) ) ) {
+		buffer = phys_to_user ( addr.buffer_phys );
+		DBGC2 ( int13, "%08llx",
+			( ( unsigned long long ) addr.buffer_phys ) );
+	} else {
+		buffer = real_to_user ( addr.buffer.segment,
+					addr.buffer.offset );
+		DBGC2 ( int13, "%04x:%04x", addr.buffer.segment,
+			addr.buffer.offset );
+	}
+	if ( addr.count <= 0x7f ) {
+		count = addr.count;
+	} else if ( addr.count == 0xff ) {
+		count = addr.long_count;
+	} else {
+		DBGC2 ( int13, " <invalid count %#02x>\n", addr.count );
+		return -INT13_STATUS_INVALID;
+	}
+	DBGC2 ( int13, " (count %ld)\n", count );
+
+	/* Read from / write to block device */
+	if ( ( rc = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x extended I/O failed: %s\n",
+		       int13->drive, strerror ( rc ) );
+		/* Record that no blocks were transferred successfully */
+		addr.count = 0;
+		put_real ( addr.count, ix86->segs.ds,
+			   ( ix86->regs.si +
+			     offsetof ( typeof ( addr ), count ) ) );
+		return -INT13_STATUS_READ_ERROR;
+	}
+
+	return 0;
+}
+
+/**
+ * INT 13, 42 - Extended read
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+static int int13_extended_read ( struct int13_drive *int13,
+				 struct i386_all_regs *ix86 ) {
+	DBGC2 ( int13, "Extended read: " );
+	return int13_extended_rw ( int13, ix86, block_read );
+}
+
+/**
+ * INT 13, 43 - Extended write
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+static int int13_extended_write ( struct int13_drive *int13,
+				  struct i386_all_regs *ix86 ) {
+	DBGC2 ( int13, "Extended write: " );
+	return int13_extended_rw ( int13, ix86, block_write );
+}
+
+/**
+ * INT 13, 44 - Verify sectors
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+static int int13_extended_verify ( struct int13_drive *int13,
+				   struct i386_all_regs *ix86 ) {
+	struct int13_disk_address addr;
+	uint64_t lba;
+	unsigned long count;
+
+	/* Read parameters from disk address structure */
+	if ( DBG_EXTRA ) {
+		copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
+				 sizeof ( addr ));
+		lba = addr.lba;
+		count = addr.count;
+		DBGC2 ( int13, "Verify: LBA %08llx (count %ld)\n",
+			( ( unsigned long long ) lba ), count );
+	}
+
+	/* We have no mechanism for verifying sectors */
+	return -INT13_STATUS_INVALID;
+}
+
+/**
+ * INT 13, 44 - Extended seek
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+static int int13_extended_seek ( struct int13_drive *int13,
+				 struct i386_all_regs *ix86 ) {
+	struct int13_disk_address addr;
+	uint64_t lba;
+	unsigned long count;
+
+	/* Read parameters from disk address structure */
+	if ( DBG_EXTRA ) {
+		copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
+				 sizeof ( addr ));
+		lba = addr.lba;
+		count = addr.count;
+		DBGC2 ( int13, "Seek: LBA %08llx (count %ld)\n",
+			( ( unsigned long long ) lba ), count );
+	}
+
+	/* Ignore and return success */
+	return 0;
+}
+
+/**
+ * Build device path information
+ *
+ * @v int13		Emulated drive
+ * @v dpi		Device path information
+ * @ret rc		Return status code
+ */
+static int int13_device_path_info ( struct int13_drive *int13,
+				    struct edd_device_path_information *dpi ) {
+	struct device *device;
+	struct device_description *desc;
+	unsigned int i;
+	uint8_t sum = 0;
+	int rc;
+
+	/* Reopen block device if necessary */
+	if ( ( int13->block_rc != 0 ) &&
+	     ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+		return rc;
+
+	/* Get underlying hardware device */
+	device = identify_device ( &int13->block );
+	if ( ! device ) {
+		DBGC ( int13, "INT13 drive %02x cannot identify hardware "
+		       "device\n", int13->drive );
+		return -ENODEV;
+	}
+
+	/* Fill in bus type and interface path */
+	desc = &device->desc;
+	switch ( desc->bus_type ) {
+	case BUS_TYPE_PCI:
+		dpi->host_bus_type.type = EDD_BUS_TYPE_PCI;
+		dpi->interface_path.pci.bus = PCI_BUS ( desc->location );
+		dpi->interface_path.pci.slot = PCI_SLOT ( desc->location );
+		dpi->interface_path.pci.function = PCI_FUNC ( desc->location );
+		dpi->interface_path.pci.channel = 0xff; /* unused */
+		break;
+	default:
+		DBGC ( int13, "INT13 drive %02x unrecognised bus type %d\n",
+		       int13->drive, desc->bus_type );
+		return -ENOTSUP;
+	}
+
+	/* Get EDD block device description */
+	if ( ( rc = edd_describe ( &int13->block, &dpi->interface_type,
+				   &dpi->device_path ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x cannot identify block device: "
+		       "%s\n", int13->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Fill in common fields and fix checksum */
+	dpi->key = EDD_DEVICE_PATH_INFO_KEY;
+	dpi->len = sizeof ( *dpi );
+	for ( i = 0 ; i < sizeof ( *dpi ) ; i++ )
+		sum += *( ( ( uint8_t * ) dpi ) + i );
+	dpi->checksum -= sum;
+
+	return 0;
+}
+
+/**
+ * INT 13, 48 - Get extended parameters
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Drive parameter table
+ * @ret status		Status code
+ */
+static int int13_get_extended_parameters ( struct int13_drive *int13,
+					   struct i386_all_regs *ix86 ) {
+	struct int13_disk_parameters params;
+	struct segoff address;
+	size_t len = sizeof ( params );
+	uint16_t bufsize;
+	int rc;
+
+	/* Get buffer size */
+	get_real ( bufsize, ix86->segs.ds,
+		   ( ix86->regs.si + offsetof ( typeof ( params ), bufsize )));
+
+	DBGC2 ( int13, "Get extended drive parameters to %04x:%04x+%02x\n",
+		ix86->segs.ds, ix86->regs.si, bufsize );
+
+	/* Build drive parameters */
+	memset ( &params, 0, sizeof ( params ) );
+	params.flags = INT13_FL_DMA_TRANSPARENT;
+	if ( ( int13->cylinders < 1024 ) &&
+	     ( int13_capacity ( int13 ) <= INT13_MAX_CHS_SECTORS ) ) {
+		params.flags |= INT13_FL_CHS_VALID;
+	}
+	params.cylinders = int13->cylinders;
+	params.heads = int13->heads;
+	params.sectors_per_track = int13->sectors_per_track;
+	params.sectors = int13_capacity ( int13 );
+	params.sector_size = int13_blksize ( int13 );
+	memset ( &params.dpte, 0xff, sizeof ( params.dpte ) );
+	if ( ( rc = int13_device_path_info ( int13, &params.dpi ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not provide device "
+		       "path information: %s\n",
+		       int13->drive, strerror ( rc ) );
+		len = offsetof ( typeof ( params ), dpi );
+	}
+
+	/* Calculate returned "buffer size" (which will be less than
+	 * the length actually copied if device path information is
+	 * present).
+	 */
+	if ( bufsize < offsetof ( typeof ( params ), dpte ) )
+		return -INT13_STATUS_INVALID;
+	if ( bufsize < offsetof ( typeof ( params ), dpi ) ) {
+		params.bufsize = offsetof ( typeof ( params ), dpte );
+	} else {
+		params.bufsize = offsetof ( typeof ( params ), dpi );
+	}
+
+	DBGC ( int13, "INT 13 drive %02x described using extended "
+	       "parameters:\n", int13->drive );
+	address.segment = ix86->segs.ds;
+	address.offset = ix86->regs.si;
+	DBGC_HDA ( int13, address, &params, len );
+
+	/* Return drive parameters */
+	if ( len > bufsize )
+		len = bufsize;
+	copy_to_real ( ix86->segs.ds, ix86->regs.si, &params, len );
+
+	return 0;
+}
+
+/**
+ * INT 13, 4b - Get status or terminate CD-ROM emulation
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Specification packet
+ * @ret status		Status code
+ */
+static int int13_cdrom_status_terminate ( struct int13_drive *int13,
+					  struct i386_all_regs *ix86 ) {
+	struct int13_cdrom_specification specification;
+
+	DBGC2 ( int13, "Get CD-ROM emulation status to %04x:%04x%s\n",
+		ix86->segs.ds, ix86->regs.si,
+		( ix86->regs.al ? "" : " and terminate" ) );
+
+	/* Fail if we are not a CD-ROM */
+	if ( ! int13->is_cdrom ) {
+		DBGC ( int13, "INT13 drive %02x is not a CD-ROM\n",
+		       int13->drive );
+		return -INT13_STATUS_INVALID;
+	}
+
+	/* Build specification packet */
+	memset ( &specification, 0, sizeof ( specification ) );
+	specification.size = sizeof ( specification );
+	specification.drive = int13->drive;
+
+	/* Return specification packet */
+	copy_to_real ( ix86->segs.ds, ix86->regs.si, &specification,
+		       sizeof ( specification ) );
+
+	return 0;
+}
+
+
+/**
+ * INT 13, 4d - Read CD-ROM boot catalog
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Command packet
+ * @ret status		Status code
+ */
+static int int13_cdrom_read_boot_catalog ( struct int13_drive *int13,
+					   struct i386_all_regs *ix86 ) {
+	struct int13_cdrom_boot_catalog_command command;
+	int rc;
+
+	/* Read parameters from command packet */
+	copy_from_real ( &command, ix86->segs.ds, ix86->regs.si,
+			 sizeof ( command ) );
+	DBGC2 ( int13, "Read CD-ROM boot catalog to %08x\n", command.buffer );
+
+	/* Fail if we have no boot catalog */
+	if ( ! int13->boot_catalog ) {
+		DBGC ( int13, "INT13 drive %02x has no boot catalog\n",
+		       int13->drive );
+		return -INT13_STATUS_INVALID;
+	}
+
+	/* Read from boot catalog */
+	if ( ( rc = int13_rw ( int13, ( int13->boot_catalog + command.start ),
+			       command.count, phys_to_user ( command.buffer ),
+			       block_read ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not read boot catalog: "
+		       "%s\n", int13->drive, strerror ( rc ) );
+		return -INT13_STATUS_READ_ERROR;
+	}
+
+	return 0;
+}
+
+/**
+ * INT 13 handler
+ *
+ */
+static __asmcall void int13 ( struct i386_all_regs *ix86 ) {
+	int command = ix86->regs.ah;
+	unsigned int bios_drive = ix86->regs.dl;
+	struct int13_drive *int13;
+	int status;
+
+	/* Check BIOS hasn't killed off our drive */
+	int13_check_num_drives();
+
+	list_for_each_entry ( int13, &int13s, list ) {
+
+		if ( bios_drive != int13->drive ) {
+			/* Remap any accesses to this drive's natural number */
+			if ( bios_drive == int13->natural_drive ) {
+				DBGC2 ( int13, "INT13,%02x (%02x) remapped to "
+					"(%02x)\n", ix86->regs.ah,
+					bios_drive, int13->drive );
+				ix86->regs.dl = int13->drive;
+				return;
+			} else if ( ( ( bios_drive & 0x7f ) == 0x7f ) &&
+				    ( command == INT13_CDROM_STATUS_TERMINATE )
+				    && int13->is_cdrom ) {
+				/* Catch non-drive-specific CD-ROM calls */
+			} else {
+				continue;
+			}
+		}
+		
+		DBGC2 ( int13, "INT13,%02x (%02x): ",
+			ix86->regs.ah, bios_drive );
+
+		switch ( command ) {
+		case INT13_RESET:
+			status = int13_reset ( int13, ix86 );
+			break;
+		case INT13_GET_LAST_STATUS:
+			status = int13_get_last_status ( int13, ix86 );
+			break;
+		case INT13_READ_SECTORS:
+			status = int13_read_sectors ( int13, ix86 );
+			break;
+		case INT13_WRITE_SECTORS:
+			status = int13_write_sectors ( int13, ix86 );
+			break;
+		case INT13_GET_PARAMETERS:
+			status = int13_get_parameters ( int13, ix86 );
+			break;
+		case INT13_GET_DISK_TYPE:
+			status = int13_get_disk_type ( int13, ix86 );
+			break;
+		case INT13_EXTENSION_CHECK:
+			status = int13_extension_check ( int13, ix86 );
+			break;
+		case INT13_EXTENDED_READ:
+			status = int13_extended_read ( int13, ix86 );
+			break;
+		case INT13_EXTENDED_WRITE:
+			status = int13_extended_write ( int13, ix86 );
+			break;
+		case INT13_EXTENDED_VERIFY:
+			status = int13_extended_verify ( int13, ix86 );
+			break;
+		case INT13_EXTENDED_SEEK:
+			status = int13_extended_seek ( int13, ix86 );
+			break;
+		case INT13_GET_EXTENDED_PARAMETERS:
+			status = int13_get_extended_parameters ( int13, ix86 );
+			break;
+		case INT13_CDROM_STATUS_TERMINATE:
+			status = int13_cdrom_status_terminate ( int13, ix86 );
+			break;
+		case INT13_CDROM_READ_BOOT_CATALOG:
+			status = int13_cdrom_read_boot_catalog ( int13, ix86 );
+			break;
+		default:
+			DBGC2 ( int13, "*** Unrecognised INT13 ***\n" );
+			status = -INT13_STATUS_INVALID;
+			break;
+		}
+
+		/* Store status for INT 13,01 */
+		int13->last_status = status;
+
+		/* Negative status indicates an error */
+		if ( status < 0 ) {
+			status = -status;
+			DBGC ( int13, "INT13,%02x (%02x) failed with status "
+			       "%02x\n", ix86->regs.ah, int13->drive, status );
+		} else {
+			ix86->flags &= ~CF;
+		}
+		ix86->regs.ah = status;
+
+		/* Set OF to indicate to wrapper not to chain this call */
+		ix86->flags |= OF;
+
+		return;
+	}
+}
+
+/**
+ * Hook INT 13 handler
+ *
+ */
+static void int13_hook_vector ( void ) {
+	/* Assembly wrapper to call int13().  int13() sets OF if we
+	 * should not chain to the previous handler.  (The wrapper
+	 * clears CF and OF before calling int13()).
+	 */
+	__asm__  __volatile__ (
+	       TEXT16_CODE ( "\nint13_wrapper:\n\t"
+			     /* Preserve %ax and %dx for future reference */
+			     "pushw %%bp\n\t"
+			     "movw %%sp, %%bp\n\t"			     
+			     "pushw %%ax\n\t"
+			     "pushw %%dx\n\t"
+			     /* Clear OF, set CF, call int13() */
+			     "orb $0, %%al\n\t" 
+			     "stc\n\t"
+			     "pushl %0\n\t"
+			     "pushw %%cs\n\t"
+			     "call prot_call\n\t"
+			     /* Chain if OF not set */
+			     "jo 1f\n\t"
+			     "pushfw\n\t"
+			     "lcall *%%cs:int13_vector\n\t"
+			     "\n1:\n\t"
+			     /* Overwrite flags for iret */
+			     "pushfw\n\t"
+			     "popw 6(%%bp)\n\t"
+			     /* Fix up %dl:
+			      *
+			      * INT 13,15 : do nothing if hard disk
+			      * INT 13,08 : load with number of drives
+			      * all others: restore original value
+			      */
+			     "cmpb $0x15, -1(%%bp)\n\t"
+			     "jne 2f\n\t"
+			     "testb $0x80, -4(%%bp)\n\t"
+			     "jnz 3f\n\t"
+			     "\n2:\n\t"
+			     "movb -4(%%bp), %%dl\n\t"
+			     "cmpb $0x08, -1(%%bp)\n\t"
+			     "jne 3f\n\t"
+			     "testb $0x80, %%dl\n\t"
+			     "movb %%cs:num_drives, %%dl\n\t"
+			     "jnz 3f\n\t"
+			     "movb %%cs:num_fdds, %%dl\n\t"
+			     /* Return */
+			     "\n3:\n\t"
+			     "movw %%bp, %%sp\n\t"
+			     "popw %%bp\n\t"
+			     "iret\n\t" )
+	       : : "i" ( int13 ) );
+
+	hook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
+			      &int13_vector );
+}
+
+/**
+ * Unhook INT 13 handler
+ */
+static void int13_unhook_vector ( void ) {
+	unhook_bios_interrupt ( 0x13, ( unsigned int ) int13_wrapper,
+				&int13_vector );
+}
+
+/**
+ * Check INT13 emulated drive flow control window
+ *
+ * @v int13		Emulated drive
+ */
+static size_t int13_block_window ( struct int13_drive *int13 __unused ) {
+
+	/* We are never ready to receive data via this interface.
+	 * This prevents objects that support both block and stream
+	 * interfaces from attempting to send us stream data.
+	 */
+	return 0;
+}
+
+/**
+ * Handle INT 13 emulated drive underlying block device closing
+ *
+ * @v int13		Emulated drive
+ * @v rc		Reason for close
+ */
+static void int13_block_close ( struct int13_drive *int13, int rc ) {
+
+	/* Any closing is an error from our point of view */
+	if ( rc == 0 )
+		rc = -ENOTCONN;
+
+	DBGC ( int13, "INT13 drive %02x went away: %s\n",
+	       int13->drive, strerror ( rc ) );
+
+	/* Record block device error code */
+	int13->block_rc = rc;
+
+	/* Shut down interfaces */
+	intf_restart ( &int13->block, rc );
+}
+
+/** INT 13 drive interface operations */
+static struct interface_operation int13_block_op[] = {
+	INTF_OP ( xfer_window, struct int13_drive *, int13_block_window ),
+	INTF_OP ( intf_close, struct int13_drive *, int13_block_close ),
+};
+
+/** INT 13 drive interface descriptor */
+static struct interface_descriptor int13_block_desc =
+	INTF_DESC ( struct int13_drive, block, int13_block_op );
+
+/**
+ * Free INT 13 emulated drive
+ *
+ * @v refcnt		Reference count
+ */
+static void int13_free ( struct refcnt *refcnt ) {
+	struct int13_drive *int13 =
+		container_of ( refcnt, struct int13_drive, refcnt );
+
+	uri_put ( int13->uri );
+	free ( int13 );
+}
+
+/**
+ * Hook INT 13 emulated drive
+ *
+ * @v uri		URI
+ * @v drive		Drive number
+ * @ret rc		Return status code
+ *
+ * Registers the drive with the INT 13 emulation subsystem, and hooks
+ * the INT 13 interrupt vector (if not already hooked).
+ */
+static int int13_hook ( struct uri *uri, unsigned int drive ) {
+	struct int13_drive *int13;
+	unsigned int natural_drive;
+	void *scratch;
+	int rc;
+
+	/* Calculate natural drive number */
+	int13_sync_num_drives();
+	natural_drive = ( ( drive & 0x80 ) ? ( num_drives | 0x80 ) : num_fdds );
+
+	/* Check that drive number is not in use */
+	list_for_each_entry ( int13, &int13s, list ) {
+		if ( int13->drive == drive ) {
+			rc = -EADDRINUSE;
+			goto err_in_use;
+		}
+	}
+
+	/* Allocate and initialise structure */
+	int13 = zalloc ( sizeof ( *int13 ) );
+	if ( ! int13 ) {
+		rc = -ENOMEM;
+		goto err_zalloc;
+	}
+	ref_init ( &int13->refcnt, int13_free );
+	intf_init ( &int13->block, &int13_block_desc, &int13->refcnt );
+	int13->uri = uri_get ( uri );
+	int13->drive = drive;
+	int13->natural_drive = natural_drive;
+
+	/* Open block device interface */
+	if ( ( rc = int13_reopen_block ( int13 ) ) != 0 )
+		goto err_reopen_block;
+
+	/* Read device capacity */
+	if ( ( rc = int13_read_capacity ( int13 ) ) != 0 )
+		goto err_read_capacity;
+
+	/* Allocate scratch area */
+	scratch = malloc ( int13_blksize ( int13 ) );
+	if ( ! scratch )
+		goto err_alloc_scratch;
+
+	/* Parse parameters, if present */
+	if ( ( rc = int13_parse_iso9660 ( int13, scratch ) ) != 0 )
+		goto err_parse_iso9660;
+
+	/* Give drive a default geometry */
+	if ( ( rc = int13_guess_geometry ( int13, scratch ) ) != 0 )
+		goto err_guess_geometry;
+
+	DBGC ( int13, "INT13 drive %02x (naturally %02x) registered with C/H/S "
+	       "geometry %d/%d/%d\n", int13->drive, int13->natural_drive,
+	       int13->cylinders, int13->heads, int13->sectors_per_track );
+
+	/* Hook INT 13 vector if not already hooked */
+	if ( list_empty ( &int13s ) ) {
+		int13_hook_vector();
+		devices_get();
+	}
+
+	/* Add to list of emulated drives */
+	list_add ( &int13->list, &int13s );
+
+	/* Update BIOS drive count */
+	int13_sync_num_drives();
+
+	free ( scratch );
+	return 0;
+
+ err_guess_geometry:
+ err_parse_iso9660:
+	free ( scratch );
+ err_alloc_scratch:
+ err_read_capacity:
+ err_reopen_block:
+	intf_shutdown ( &int13->block, rc );
+	ref_put ( &int13->refcnt );
+ err_zalloc:
+ err_in_use:
+	return rc;
+}
+
+/**
+ * Find INT 13 emulated drive by drive number
+ *
+ * @v drive		Drive number
+ * @ret int13		Emulated drive, or NULL
+ */
+static struct int13_drive * int13_find ( unsigned int drive ) {
+	struct int13_drive *int13;
+
+	list_for_each_entry ( int13, &int13s, list ) {
+		if ( int13->drive == drive )
+			return int13;
+	}
+	return NULL;
+}
+
+/**
+ * Unhook INT 13 emulated drive
+ *
+ * @v drive		Drive number
+ *
+ * Unregisters the drive from the INT 13 emulation subsystem.  If this
+ * is the last emulated drive, the INT 13 vector is unhooked (if
+ * possible).
+ */
+static void int13_unhook ( unsigned int drive ) {
+	struct int13_drive *int13;
+
+	/* Find drive */
+	int13 = int13_find ( drive );
+	if ( ! int13 ) {
+		DBG ( "INT13 cannot find emulated drive %02x\n", drive );
+		return;
+	}
+
+	/* Shut down interfaces */
+	intf_shutdown ( &int13->block, 0 );
+
+	/* Remove from list of emulated drives */
+	list_del ( &int13->list );
+
+	/* Should adjust BIOS drive count, but it's difficult
+	 * to do so reliably.
+	 */
+
+	DBGC ( int13, "INT13 drive %02x unregistered\n", int13->drive );
+
+	/* Unhook INT 13 vector if no more drives */
+	if ( list_empty ( &int13s ) ) {
+		devices_put();
+		int13_unhook_vector();
+	}
+
+	/* Drop list's reference to drive */
+	ref_put ( &int13->refcnt );
+}
+
+/**
+ * Load and verify master boot record from INT 13 drive
+ *
+ * @v drive		Drive number
+ * @v address		Boot code address to fill in
+ * @ret rc		Return status code
+ */
+static int int13_load_mbr ( unsigned int drive, struct segoff *address ) {
+	uint8_t status;
+	int discard_b, discard_c, discard_d;
+	uint16_t magic;
+
+	/* Use INT 13, 02 to read the MBR */
+	address->segment = 0;
+	address->offset = 0x7c00;
+	__asm__ __volatile__ ( REAL_CODE ( "pushw %%es\n\t"
+					   "pushl %%ebx\n\t"
+					   "popw %%bx\n\t"
+					   "popw %%es\n\t"
+					   "stc\n\t"
+					   "sti\n\t"
+					   "int $0x13\n\t"
+					   "sti\n\t" /* BIOS bugs */
+					   "jc 1f\n\t"
+					   "xorw %%ax, %%ax\n\t"
+					   "\n1:\n\t"
+					   "popw %%es\n\t" )
+			       : "=a" ( status ), "=b" ( discard_b ),
+				 "=c" ( discard_c ), "=d" ( discard_d )
+			       : "a" ( 0x0201 ), "b" ( *address ),
+				 "c" ( 1 ), "d" ( drive ) );
+	if ( status ) {
+		DBG ( "INT13 drive %02x could not read MBR (status %02x)\n",
+		      drive, status );
+		return -EIO;
+	}
+
+	/* Check magic signature */
+	get_real ( magic, address->segment,
+		   ( address->offset +
+		     offsetof ( struct master_boot_record, magic ) ) );
+	if ( magic != INT13_MBR_MAGIC ) {
+		DBG ( "INT13 drive %02x does not contain a valid MBR\n",
+		      drive );
+		return -ENOEXEC;
+	}
+
+	return 0;
+}
+
+/** El Torito boot catalog command packet */
+static struct int13_cdrom_boot_catalog_command __data16 ( eltorito_cmd ) = {
+	.size = sizeof ( struct int13_cdrom_boot_catalog_command ),
+	.count = 1,
+	.buffer = 0x7c00,
+	.start = 0,
+};
+#define eltorito_cmd __use_data16 ( eltorito_cmd )
+
+/** El Torito disk address packet */
+static struct int13_disk_address __bss16 ( eltorito_address );
+#define eltorito_address __use_data16 ( eltorito_address )
+
+/**
+ * Load and verify El Torito boot record from INT 13 drive
+ *
+ * @v drive		Drive number
+ * @v address		Boot code address to fill in
+ * @ret rc		Return status code
+ */
+static int int13_load_eltorito ( unsigned int drive, struct segoff *address ) {
+	struct {
+		struct eltorito_validation_entry valid;
+		struct eltorito_boot_entry boot;
+	} __attribute__ (( packed )) catalog;
+	uint8_t status;
+
+	/* Use INT 13, 4d to read the boot catalog */
+	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+					   "sti\n\t"
+					   "int $0x13\n\t"
+					   "sti\n\t" /* BIOS bugs */
+					   "jc 1f\n\t"
+					   "xorw %%ax, %%ax\n\t"
+					   "\n1:\n\t" )
+			       : "=a" ( status )
+			       : "a" ( 0x4d00 ), "d" ( drive ),
+				 "S" ( __from_data16 ( &eltorito_cmd ) ) );
+	if ( status ) {
+		DBG ( "INT13 drive %02x could not read El Torito boot catalog "
+		      "(status %02x)\n", drive, status );
+		return -EIO;
+	}
+	copy_from_user ( &catalog, phys_to_user ( eltorito_cmd.buffer ), 0,
+			 sizeof ( catalog ) );
+
+	/* Sanity checks */
+	if ( catalog.valid.platform_id != ELTORITO_PLATFORM_X86 ) {
+		DBG ( "INT13 drive %02x El Torito specifies unknown platform "
+		      "%02x\n", drive, catalog.valid.platform_id );
+		return -ENOEXEC;
+	}
+	if ( catalog.boot.indicator != ELTORITO_BOOTABLE ) {
+		DBG ( "INT13 drive %02x El Torito is not bootable\n", drive );
+		return -ENOEXEC;
+	}
+	if ( catalog.boot.media_type != ELTORITO_NO_EMULATION ) {
+		DBG ( "INT13 drive %02x El Torito requires emulation "
+		       "type %02x\n", drive, catalog.boot.media_type );
+		return -ENOTSUP;
+	}
+	DBG ( "INT13 drive %02x El Torito boot image at LBA %08x (count %d)\n",
+	      drive, catalog.boot.start, catalog.boot.length );
+	address->segment = ( catalog.boot.load_segment ?
+			     catalog.boot.load_segment : 0x7c0 );
+	address->offset = 0;
+	DBG ( "INT13 drive %02x El Torito boot image loads at %04x:%04x\n",
+	      drive, address->segment, address->offset );
+
+	/* Use INT 13, 42 to read the boot image */
+	eltorito_address.bufsize =
+		offsetof ( typeof ( eltorito_address ), buffer_phys );
+	eltorito_address.count = catalog.boot.length;
+	eltorito_address.buffer = *address;
+	eltorito_address.lba = catalog.boot.start;
+	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+					   "sti\n\t"
+					   "int $0x13\n\t"
+					   "sti\n\t" /* BIOS bugs */
+					   "jc 1f\n\t"
+					   "xorw %%ax, %%ax\n\t"
+					   "\n1:\n\t" )
+			       : "=a" ( status )
+			       : "a" ( 0x4200 ), "d" ( drive ),
+				 "S" ( __from_data16 ( &eltorito_address ) ) );
+	if ( status ) {
+		DBG ( "INT13 drive %02x could not read El Torito boot image "
+		      "(status %02x)\n", drive, status );
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/**
+ * Attempt to boot from an INT 13 drive
+ *
+ * @v drive		Drive number
+ * @ret rc		Return status code
+ *
+ * This boots from the specified INT 13 drive by loading the Master
+ * Boot Record to 0000:7c00 and jumping to it.  INT 18 is hooked to
+ * capture an attempt by the MBR to boot the next device.  (This is
+ * the closest thing to a return path from an MBR).
+ *
+ * Note that this function can never return success, by definition.
+ */
+static int int13_boot ( unsigned int drive ) {
+	struct memory_map memmap;
+	struct segoff address;
+	int rc;
+
+	/* Look for a usable boot sector */
+	if ( ( ( rc = int13_load_mbr ( drive, &address ) ) != 0 ) &&
+	     ( ( rc = int13_load_eltorito ( drive, &address ) ) != 0 ) )
+		return rc;
+
+	/* Dump out memory map prior to boot, if memmap debugging is
+	 * enabled.  Not required for program flow, but we have so
+	 * many problems that turn out to be memory-map related that
+	 * it's worth doing.
+	 */
+	get_memmap ( &memmap );
+
+	/* Jump to boot sector */
+	if ( ( rc = call_bootsector ( address.segment, address.offset,
+				      drive ) ) != 0 ) {
+		DBG ( "INT13 drive %02x boot returned: %s\n",
+		      drive, strerror ( rc ) );
+		return rc;
+	}
+
+	return -ECANCELED; /* -EIMPOSSIBLE */
+}
+
+/** A boot firmware table generated by iPXE */
+union xbft_table {
+	/** ACPI header */
+	struct acpi_description_header acpi;
+	/** Padding */
+	char pad[768];
+};
+
+/** The boot firmware table generated by iPXE */
+static union xbft_table __bss16 ( xbftab ) __attribute__ (( aligned ( 16 ) ));
+#define xbftab __use_data16 ( xbftab )
+
+/**
+ * Describe INT 13 emulated drive for SAN-booted operating system
+ *
+ * @v drive		Drive number
+ * @ret rc		Return status code
+ */
+static int int13_describe ( unsigned int drive ) {
+	struct int13_drive *int13;
+	struct segoff xbft_address;
+	int rc;
+
+	/* Find drive */
+	int13 = int13_find ( drive );
+	if ( ! int13 ) {
+		DBG ( "INT13 cannot find emulated drive %02x\n", drive );
+		return -ENODEV;
+	}
+
+	/* Reopen block device if necessary */
+	if ( ( int13->block_rc != 0 ) &&
+	     ( ( rc = int13_reopen_block ( int13 ) ) != 0 ) )
+		return rc;
+
+	/* Clear table */
+	memset ( &xbftab, 0, sizeof ( xbftab ) );
+
+	/* Fill in common parameters */
+	strncpy ( xbftab.acpi.oem_id, "FENSYS",
+		  sizeof ( xbftab.acpi.oem_id ) );
+	strncpy ( xbftab.acpi.oem_table_id, "iPXE",
+		  sizeof ( xbftab.acpi.oem_table_id ) );
+
+	/* Fill in remaining parameters */
+	if ( ( rc = acpi_describe ( &int13->block, &xbftab.acpi,
+				    sizeof ( xbftab ) ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not create ACPI "
+		       "description: %s\n", int13->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Fix up ACPI checksum */
+	acpi_fix_checksum ( &xbftab.acpi );
+	xbft_address.segment = rm_ds;
+	xbft_address.offset = __from_data16 ( &xbftab );
+	DBGC ( int13, "INT13 drive %02x described using boot firmware "
+	       "table:\n", int13->drive );
+	DBGC_HDA ( int13, xbft_address, &xbftab,
+		   le32_to_cpu ( xbftab.acpi.length ) );
+
+	return 0;
+}
+
+PROVIDE_SANBOOT_INLINE ( pcbios, san_default_drive );
+PROVIDE_SANBOOT ( pcbios, san_hook, int13_hook );
+PROVIDE_SANBOOT ( pcbios, san_unhook, int13_unhook );
+PROVIDE_SANBOOT ( pcbios, san_boot, int13_boot );
+PROVIDE_SANBOOT ( pcbios, san_describe, int13_describe );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/memtop_umalloc.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/memtop_umalloc.c
new file mode 100644
index 000000000..c382e3c36
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/memtop_umalloc.c
@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * External memory allocation
+ *
+ */
+
+#include <limits.h>
+#include <errno.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/hidemem.h>
+#include <ipxe/io.h>
+#include <ipxe/memblock.h>
+#include <ipxe/umalloc.h>
+
+/** Alignment of external allocated memory */
+#define EM_ALIGN ( 4 * 1024 )
+
+/** Equivalent of NOWHERE for user pointers */
+#define UNOWHERE ( ~UNULL )
+
+/** An external memory block */
+struct external_memory {
+	/** Size of this memory block (excluding this header) */
+	size_t size;
+	/** Block is currently in use */
+	int used;
+};
+
+/** Top of heap */
+static userptr_t top = UNULL;
+
+/** Bottom of heap (current lowest allocated block) */
+static userptr_t bottom = UNULL;
+
+/** Remaining space on heap */
+static size_t heap_size;
+
+/**
+ * Initialise external heap
+ *
+ */
+static void init_eheap ( void ) {
+	userptr_t base;
+
+	heap_size = largest_memblock ( &base );
+	bottom = top = userptr_add ( base, heap_size );
+	DBG ( "External heap grows downwards from %lx (size %zx)\n",
+	      user_to_phys ( top, 0 ), heap_size );
+}
+
+/**
+ * Collect free blocks
+ *
+ */
+static void ecollect_free ( void ) {
+	struct external_memory extmem;
+	size_t len;
+
+	/* Walk the free list and collect empty blocks */
+	while ( bottom != top ) {
+		copy_from_user ( &extmem, bottom, -sizeof ( extmem ),
+				 sizeof ( extmem ) );
+		if ( extmem.used )
+			break;
+		DBG ( "EXTMEM freeing [%lx,%lx)\n", user_to_phys ( bottom, 0 ),
+		      user_to_phys ( bottom, extmem.size ) );
+		len = ( extmem.size + sizeof ( extmem ) );
+		bottom = userptr_add ( bottom, len );
+		heap_size += len;
+	}
+}
+
+/**
+ * Reallocate external memory
+ *
+ * @v old_ptr		Memory previously allocated by umalloc(), or UNULL
+ * @v new_size		Requested size
+ * @ret new_ptr		Allocated memory, or UNULL
+ *
+ * Calling realloc() with a new size of zero is a valid way to free a
+ * memory block.
+ */
+static userptr_t memtop_urealloc ( userptr_t ptr, size_t new_size ) {
+	struct external_memory extmem;
+	userptr_t new = ptr;
+	size_t align;
+
+	/* (Re)initialise external memory allocator if necessary */
+	if ( bottom == top )
+		init_eheap();
+
+	/* Get block properties into extmem */
+	if ( ptr && ( ptr != UNOWHERE ) ) {
+		/* Determine old size */
+		copy_from_user ( &extmem, ptr, -sizeof ( extmem ),
+				 sizeof ( extmem ) );
+	} else {
+		/* Create a zero-length block */
+		if ( heap_size < sizeof ( extmem ) ) {
+			DBG ( "EXTMEM out of space\n" );
+			return UNULL;
+		}
+		ptr = bottom = userptr_add ( bottom, -sizeof ( extmem ) );
+		heap_size -= sizeof ( extmem );
+		DBG ( "EXTMEM allocating [%lx,%lx)\n",
+		      user_to_phys ( ptr, 0 ), user_to_phys ( ptr, 0 ) );
+		extmem.size = 0;
+	}
+	extmem.used = ( new_size > 0 );
+
+	/* Expand/shrink block if possible */
+	if ( ptr == bottom ) {
+		/* Update block */
+		if ( new_size > ( heap_size - extmem.size ) ) {
+			DBG ( "EXTMEM out of space\n" );
+			return UNULL;
+		}
+		new = userptr_add ( ptr, - ( new_size - extmem.size ) );
+		align = ( user_to_phys ( new, 0 ) & ( EM_ALIGN - 1 ) );
+		new_size += align;
+		new = userptr_add ( new, -align );
+		DBG ( "EXTMEM expanding [%lx,%lx) to [%lx,%lx)\n",
+		      user_to_phys ( ptr, 0 ),
+		      user_to_phys ( ptr, extmem.size ),
+		      user_to_phys ( new, 0 ),
+		      user_to_phys ( new, new_size ));
+		memmove_user ( new, 0, ptr, 0, ( ( extmem.size < new_size ) ?
+						 extmem.size : new_size ) );
+		bottom = new;
+		heap_size -= ( new_size - extmem.size );
+		extmem.size = new_size;
+	} else {
+		/* Cannot expand; can only pretend to shrink */
+		if ( new_size > extmem.size ) {
+			/* Refuse to expand */
+			DBG ( "EXTMEM cannot expand [%lx,%lx)\n",
+			      user_to_phys ( ptr, 0 ),
+			      user_to_phys ( ptr, extmem.size ) );
+			return UNULL;
+		}
+	}
+
+	/* Write back block properties */
+	copy_to_user ( new, -sizeof ( extmem ), &extmem,
+		       sizeof ( extmem ) );
+
+	/* Collect any free blocks and update hidden memory region */
+	ecollect_free();
+	hide_umalloc ( user_to_phys ( bottom, ( ( bottom == top ) ?
+						0 : -sizeof ( extmem ) ) ),
+		       user_to_phys ( top, 0 ) );
+
+	return ( new_size ? new : UNOWHERE );
+}
+
+PROVIDE_UMALLOC ( memtop, urealloc, memtop_urealloc );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/pcibios.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/pcibios.c
new file mode 100644
index 000000000..61873039f
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/pcibios.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <ipxe/pci.h>
+#include <realmode.h>
+
+/** @file
+ *
+ * PCI configuration space access via PCI BIOS
+ *
+ */
+
+/**
+ * Determine number of PCI buses within system
+ *
+ * @ret num_bus		Number of buses
+ */
+static int pcibios_num_bus ( void ) {
+	int discard_a, discard_D;
+	uint8_t max_bus;
+
+	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+					   "int $0x1a\n\t"
+					   "jnc 1f\n\t"
+					   "xorw %%cx, %%cx\n\t"
+					   "\n1:\n\t" )
+			       : "=c" ( max_bus ), "=a" ( discard_a ),
+				 "=D" ( discard_D )
+			       : "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 ),
+				 "D" ( 0 )
+			       : "ebx", "edx" );
+
+	return ( max_bus + 1 );
+}
+
+/**
+ * Read configuration space via PCI BIOS
+ *
+ * @v pci	PCI device
+ * @v command	PCI BIOS command
+ * @v value	Value read
+ * @ret rc	Return status code
+ */
+int pcibios_read ( struct pci_device *pci, uint32_t command, uint32_t *value ){
+	int discard_b, discard_D;
+	int status;
+
+	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+					   "int $0x1a\n\t"
+					   "jnc 1f\n\t"
+					   "xorl %%eax, %%eax\n\t"
+					   "decl %%eax\n\t"
+					   "movl %%eax, %%ecx\n\t"
+					   "\n1:\n\t" )
+			       : "=a" ( status ), "=b" ( discard_b ),
+				 "=c" ( *value ), "=D" ( discard_D )
+			       : "a" ( command >> 16 ), "D" ( command ),
+				 "b" ( pci->busdevfn )
+			       : "edx" );
+
+	return ( ( status >> 8 ) & 0xff );
+}
+
+/**
+ * Write configuration space via PCI BIOS
+ *
+ * @v pci	PCI device
+ * @v command	PCI BIOS command
+ * @v value	Value to be written
+ * @ret rc	Return status code
+ */
+int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
+	int discard_b, discard_c, discard_D;
+	int status;
+
+	__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
+					   "int $0x1a\n\t"
+					   "jnc 1f\n\t"
+					   "movb $0xff, %%ah\n\t"
+					   "\n1:\n\t" )
+			       : "=a" ( status ), "=b" ( discard_b ),
+				 "=c" ( discard_c ), "=D" ( discard_D )
+			       : "a" ( command >> 16 ),	"D" ( command ),
+			         "b" ( pci->busdevfn ), "c" ( value )
+			       : "edx" );
+	
+	return ( ( status >> 8 ) & 0xff );
+}
+
+PROVIDE_PCIAPI ( pcbios, pci_num_bus, pcibios_num_bus );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_byte );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_word );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_dword );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_byte );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_word );
+PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_dword );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_entropy.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_entropy.c
new file mode 100644
index 000000000..fad421c2a
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_entropy.c
@@ -0,0 +1,199 @@
+/*
+ * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * RTC-based entropy source
+ *
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <biosint.h>
+#include <pic8259.h>
+#include <rtc.h>
+#include <ipxe/entropy.h>
+
+/** RTC "interrupt triggered" flag */
+static uint8_t __text16 ( rtc_flag );
+#define rtc_flag __use_text16 ( rtc_flag )
+
+/** RTC interrupt handler */
+extern void rtc_isr ( void );
+
+/** Previous RTC interrupt handler */
+static struct segoff rtc_old_handler;
+
+/**
+ * Hook RTC interrupt handler
+ *
+ */
+static void rtc_hook_isr ( void ) {
+
+	/* RTC interrupt handler */
+	__asm__ __volatile__ (
+		TEXT16_CODE ( "\nrtc_isr:\n\t"
+			      /* Preserve registers */
+			      "pushw %%ax\n\t"
+			      /* Set "interrupt triggered" flag */
+			      "cs movb $0x01, %c0\n\t"
+			      /* Read RTC status register C to
+			       * acknowledge interrupt
+			       */
+			      "movb %3, %%al\n\t"
+			      "outb %%al, %1\n\t"
+			      "inb %2\n\t"
+			      /* Send EOI */
+			      "movb $0x20, %%al\n\t"
+			      "outb %%al, $0xa0\n\t"
+			      "outb %%al, $0x20\n\t"
+			      /* Restore registers and return */
+			      "popw %%ax\n\t"
+			      "iret\n\t" )
+		:
+		: "p" ( __from_text16 ( &rtc_flag ) ),
+		  "i" ( CMOS_ADDRESS ), "i" ( CMOS_DATA ),
+		  "i" ( RTC_STATUS_C ) );
+
+	hook_bios_interrupt ( RTC_INT, ( unsigned int ) rtc_isr,
+			      &rtc_old_handler );
+}
+
+/**
+ * Unhook RTC interrupt handler
+ *
+ */
+static void rtc_unhook_isr ( void ) {
+	int rc;
+
+	rc = unhook_bios_interrupt ( RTC_INT, ( unsigned int ) rtc_isr,
+				     &rtc_old_handler );
+	assert ( rc == 0 ); /* Should always be able to unhook */
+}
+
+/**
+ * Enable RTC interrupts
+ *
+ */
+static void rtc_enable_int ( void ) {
+	uint8_t status_b;
+
+	/* Set Periodic Interrupt Enable bit in status register B */
+	outb ( ( RTC_STATUS_B | CMOS_DISABLE_NMI ), CMOS_ADDRESS );
+	status_b = inb ( CMOS_DATA );
+	outb ( ( RTC_STATUS_B | CMOS_DISABLE_NMI ), CMOS_ADDRESS );
+	outb ( ( status_b | RTC_STATUS_B_PIE ), CMOS_DATA );
+
+	/* Re-enable NMI and reset to default address */
+	outb ( CMOS_DEFAULT_ADDRESS, CMOS_ADDRESS );
+	inb ( CMOS_DATA ); /* Discard; may be needed on some platforms */
+}
+
+/**
+ * Disable RTC interrupts
+ *
+ */
+static void rtc_disable_int ( void ) {
+	uint8_t status_b;
+
+	/* Clear Periodic Interrupt Enable bit in status register B */
+	outb ( ( RTC_STATUS_B | CMOS_DISABLE_NMI ), CMOS_ADDRESS );
+	status_b = inb ( CMOS_DATA );
+	outb ( ( RTC_STATUS_B | CMOS_DISABLE_NMI ), CMOS_ADDRESS );
+	outb ( ( status_b & ~RTC_STATUS_B_PIE ), CMOS_DATA );
+
+	/* Re-enable NMI and reset to default address */
+	outb ( CMOS_DEFAULT_ADDRESS, CMOS_ADDRESS );
+	inb ( CMOS_DATA ); /* Discard; may be needed on some platforms */
+}
+
+/**
+ * Enable entropy gathering
+ *
+ * @ret rc		Return status code
+ */
+static int rtc_entropy_enable ( void ) {
+
+	rtc_hook_isr();
+	enable_irq ( RTC_IRQ );
+	rtc_enable_int();
+
+	return 0;
+}
+
+/**
+ * Disable entropy gathering
+ *
+ */
+static void rtc_entropy_disable ( void ) {
+
+	rtc_disable_int();
+	disable_irq ( RTC_IRQ );
+	rtc_unhook_isr();
+}
+
+/**
+ * Measure a single RTC tick
+ *
+ * @ret delta		Length of RTC tick (in TSC units)
+ */
+uint8_t rtc_sample ( void ) {
+	uint32_t before;
+	uint32_t after;
+	uint32_t temp;
+
+	__asm__ __volatile__ (
+		REAL_CODE ( /* Enable interrupts */
+			    "sti\n\t"
+			    /* Wait for RTC interrupt */
+			    "cs movb %b2, %c4\n\t"
+			    "\n1:\n\t"
+			    "cs xchgb %b2, %c4\n\t" /* Serialize */
+			    "testb %b2, %b2\n\t"
+			    "jz 1b\n\t"
+			    /* Read "before" TSC */
+			    "rdtsc\n\t"
+			    /* Store "before" TSC on stack */
+			    "pushl %0\n\t"
+			    /* Wait for another RTC interrupt */
+			    "xorb %b2, %b2\n\t"
+			    "cs movb %b2, %c4\n\t"
+			    "\n1:\n\t"
+			    "cs xchgb %b2, %c4\n\t" /* Serialize */
+			    "testb %b2, %b2\n\t"
+			    "jz 1b\n\t"
+			    /* Read "after" TSC */
+			    "rdtsc\n\t"
+			    /* Retrieve "before" TSC on stack */
+			    "popl %1\n\t"
+			    /* Disable interrupts */
+			    "cli\n\t"
+			    )
+		: "=a" ( after ), "=d" ( before ), "=q" ( temp )
+		: "2" ( 0 ), "p" ( __from_text16 ( &rtc_flag ) ) );
+
+	return ( after - before );
+}
+
+PROVIDE_ENTROPY_INLINE ( rtc, min_entropy_per_sample );
+PROVIDE_ENTROPY ( rtc, entropy_enable, rtc_entropy_enable );
+PROVIDE_ENTROPY ( rtc, entropy_disable, rtc_entropy_disable );
+PROVIDE_ENTROPY_INLINE ( rtc, get_noise );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_time.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_time.c
new file mode 100644
index 000000000..67041d4ca
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/rtc_time.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * RTC-based time source
+ *
+ */
+
+#include <stdint.h>
+#include <time.h>
+#include <rtc.h>
+#include <ipxe/time.h>
+
+/**
+ * Read RTC register
+ *
+ * @v address		Register address
+ * @ret data		Data
+ */
+static unsigned int rtc_readb ( int address ) {
+	outb ( address, CMOS_ADDRESS );
+	return inb ( CMOS_DATA );
+}
+
+/**
+ * Check if RTC update is in progress
+ *
+ * @ret is_busy		RTC update is in progress
+ */
+static int rtc_is_busy ( void ) {
+	return ( rtc_readb ( RTC_STATUS_A ) & RTC_STATUS_A_UPDATE_IN_PROGRESS );
+}
+
+/**
+ * Read RTC BCD register
+ *
+ * @v address		Register address
+ * @ret value		Value
+ */
+static unsigned int rtc_readb_bcd ( int address ) {
+	unsigned int bcd;
+
+	bcd = rtc_readb ( address );
+	return ( bcd - ( 6 * ( bcd >> 4 ) ) );
+}
+
+/**
+ * Read RTC time
+ *
+ * @ret time		Time, in seconds
+ */
+static time_t rtc_read_time ( void ) {
+	unsigned int status_b;
+	int is_binary;
+	int is_24hour;
+	unsigned int ( * read_component ) ( int address );
+	struct tm tm;
+	int is_pm;
+	unsigned int hour;
+	time_t time;
+
+	/* Wait for any in-progress update to complete */
+	while ( rtc_is_busy() ) {}
+
+	/* Determine RTC mode */
+	status_b = rtc_readb ( RTC_STATUS_B );
+	is_binary = ( status_b & RTC_STATUS_B_BINARY );
+	is_24hour = ( status_b & RTC_STATUS_B_24_HOUR );
+	read_component = ( is_binary ? rtc_readb : rtc_readb_bcd );
+
+	/* Read time values */
+	tm.tm_sec = read_component ( RTC_SEC );
+	tm.tm_min = read_component ( RTC_MIN );
+	hour = read_component ( RTC_HOUR );
+	if ( ! is_24hour ) {
+		is_pm = ( hour >= 80 );
+		hour = ( ( ( ( hour & 0x7f ) % 80 ) % 12 ) +
+			 ( is_pm ? 12 : 0 ) );
+	}
+	tm.tm_hour = hour;
+	tm.tm_mday = read_component ( RTC_MDAY );
+	tm.tm_mon = ( read_component ( RTC_MON ) - 1 );
+	tm.tm_year = ( read_component ( RTC_YEAR ) +
+		       100 /* Assume we are in the 21st century, since
+			    * this code was written in 2012 */ );
+
+	DBGC ( RTC_STATUS_A, "RTCTIME is %04d-%02d-%02d %02d:%02d:%02d "
+	       "(%s,%d-hour)\n", ( tm.tm_year + 1900 ), ( tm.tm_mon + 1 ),
+	       tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec,
+	       ( is_binary ? "binary" : "BCD" ), ( is_24hour ? 24 : 12 ) );
+
+	/* Convert to seconds since the Epoch */
+	time = mktime ( &tm );
+
+	return time;
+}
+
+/**
+ * Get current time in seconds
+ *
+ * @ret time		Time, in seconds
+ */
+static time_t rtc_now ( void ) {
+	time_t time = 0;
+	time_t last_time;
+
+	/* Read time until we get two matching values in a row, in
+	 * case we end up reading a corrupted value in the middle of
+	 * an update.
+	 */
+	do {
+		last_time = time;
+		time = rtc_read_time();
+	} while ( time != last_time );
+
+	return time;
+}
+
+PROVIDE_TIME ( rtc, time_now, rtc_now );
diff --git a/qemu/roms/ipxe/src/arch/i386/interface/pcbios/vesafb.c b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/vesafb.c
new file mode 100644
index 000000000..2adc7b040
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/interface/pcbios/vesafb.c
@@ -0,0 +1,538 @@
+/*
+ * Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * VESA frame buffer console
+ *
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <limits.h>
+#include <realmode.h>
+#include <ipxe/console.h>
+#include <ipxe/io.h>
+#include <ipxe/ansicol.h>
+#include <ipxe/fbcon.h>
+#include <ipxe/vesafb.h>
+#include <config/console.h>
+
+/* Avoid dragging in BIOS console if not otherwise used */
+extern struct console_driver bios_console;
+struct console_driver bios_console __attribute__ (( weak ));
+
+/* Disambiguate the various error causes */
+#define EIO_FAILED __einfo_error ( EINFO_EIO_FAILED )
+#define EINFO_EIO_FAILED						\
+	__einfo_uniqify ( EINFO_EIO, 0x01,				\
+			  "Function call failed" )
+#define EIO_HARDWARE __einfo_error ( EINFO_EIO_HARDWARE )
+#define EINFO_EIO_HARDWARE						\
+	__einfo_uniqify ( EINFO_EIO, 0x02,				\
+			  "Not supported in current configuration" )
+#define EIO_MODE __einfo_error ( EINFO_EIO_MODE )
+#define EINFO_EIO_MODE							\
+	__einfo_uniqify ( EINFO_EIO, 0x03,				\
+			  "Invalid in current video mode" )
+#define EIO_VBE( code )							\
+	EUNIQ ( EINFO_EIO, (code), EIO_FAILED, EIO_HARDWARE, EIO_MODE )
+
+/* Set default console usage if applicable */
+#if ! ( defined ( CONSOLE_VESAFB ) && CONSOLE_EXPLICIT ( CONSOLE_VESAFB ) )
+#undef CONSOLE_VESAFB
+#define CONSOLE_VESAFB ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )
+#endif
+
+/** Font corresponding to selected character width and height */
+#define VESAFB_FONT VBE_FONT_8x16
+
+/* Forward declaration */
+struct console_driver vesafb_console __console_driver;
+
+/** A VESA frame buffer */
+struct vesafb {
+	/** Frame buffer console */
+	struct fbcon fbcon;
+	/** Physical start address */
+	physaddr_t start;
+	/** Pixel geometry */
+	struct fbcon_geometry pixel;
+	/** Margin */
+	struct fbcon_margin margin;
+	/** Colour mapping */
+	struct fbcon_colour_map map;
+	/** Font definition */
+	struct fbcon_font font;
+	/** Saved VGA mode */
+	uint8_t saved_mode;
+};
+
+/** The VESA frame buffer */
+static struct vesafb vesafb;
+
+/** Base memory buffer used for VBE calls */
+union vbe_buffer {
+	/** VBE controller information block */
+	struct vbe_controller_info controller;
+	/** VBE mode information block */
+	struct vbe_mode_info mode;
+};
+static union vbe_buffer __bss16 ( vbe_buf );
+#define vbe_buf __use_data16 ( vbe_buf )
+
+/**
+ * Convert VBE status code to iPXE status code
+ *
+ * @v status		VBE status code
+ * @ret rc		Return status code
+ */
+static int vesafb_rc ( unsigned int status ) {
+	unsigned int code;
+
+	if ( ( status & 0xff ) != 0x4f )
+		return -ENOTSUP;
+	code = ( ( status >> 8 ) & 0xff );
+	return ( code ? -EIO_VBE ( code ) : 0 );
+}
+
+/**
+ * Get font definition
+ *
+ */
+static void vesafb_font ( void ) {
+	struct segoff font;
+
+	/* Get font information
+	 *
+	 * Working around gcc bugs is icky here.  The value we want is
+	 * returned in %ebp, but there's no way to specify %ebp in an
+	 * output constraint.  We can't put %ebp in the clobber list,
+	 * because this tends to cause random build failures on some
+	 * gcc versions.  We can't manually push/pop %ebp and return
+	 * the value via a generic register output constraint, because
+	 * gcc might choose to use %ebp to satisfy that constraint
+	 * (and we have no way to prevent it from so doing).
+	 *
+	 * Work around this hideous mess by using %ecx and %edx as the
+	 * output registers, since they get clobbered anyway.
+	 */
+	__asm__ __volatile__ ( REAL_CODE ( "pushw %%bp\n\t" /* gcc bug */
+					   "int $0x10\n\t"
+					   "movw %%es, %%cx\n\t"
+					   "movw %%bp, %%dx\n\t"
+					   "popw %%bp\n\t" /* gcc bug */ )
+			       : "=c" ( font.segment ),
+				 "=d" ( font.offset )
+			       : "a" ( VBE_GET_FONT ),
+				 "b" ( VESAFB_FONT ) );
+	DBGC ( &vbe_buf, "VESAFB has font %04x at %04x:%04x\n",
+	       VESAFB_FONT, font.segment, font.offset );
+	vesafb.font.start = real_to_user ( font.segment, font.offset );
+}
+
+/**
+ * Get VBE mode list
+ *
+ * @ret mode_numbers	Mode number list (terminated with VBE_MODE_END)
+ * @ret rc		Return status code
+ *
+ * The caller is responsible for eventually freeing the mode list.
+ */
+static int vesafb_mode_list ( uint16_t **mode_numbers ) {
+	struct vbe_controller_info *controller = &vbe_buf.controller;
+	userptr_t video_mode_ptr;
+	uint16_t mode_number;
+	uint16_t status;
+	size_t len;
+	int rc;
+
+	/* Avoid returning uninitialised data on error */
+	*mode_numbers = NULL;
+
+	/* Get controller information block */
+	controller->vbe_signature = 0;
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x10" )
+			       : "=a" ( status )
+			       : "a" ( VBE_CONTROLLER_INFO ),
+				 "D" ( __from_data16 ( controller ) )
+			       : "memory", "ebx", "edx" );
+	if ( ( rc = vesafb_rc ( status ) ) != 0 ) {
+		DBGC ( &vbe_buf, "VESAFB could not get controller information: "
+		       "[%04x] %s\n", status, strerror ( rc ) );
+		return rc;
+	}
+	if ( controller->vbe_signature != VBE_CONTROLLER_SIGNATURE ) {
+		DBGC ( &vbe_buf, "VESAFB invalid controller signature "
+		       "\"%c%c%c%c\"\n", ( controller->vbe_signature >> 0 ),
+		       ( controller->vbe_signature >> 8 ),
+		       ( controller->vbe_signature >> 16 ),
+		       ( controller->vbe_signature >> 24 ) );
+		DBGC_HDA ( &vbe_buf, 0, controller, sizeof ( *controller ) );
+		return -EINVAL;
+	}
+	DBGC ( &vbe_buf, "VESAFB found VBE version %d.%d with mode list at "
+	       "%04x:%04x\n", controller->vbe_major_version,
+	       controller->vbe_minor_version,
+	       controller->video_mode_ptr.segment,
+	       controller->video_mode_ptr.offset );
+
+	/* Calculate length of mode list */
+	video_mode_ptr = real_to_user ( controller->video_mode_ptr.segment,
+					controller->video_mode_ptr.offset );
+	len = 0;
+	do {
+		copy_from_user ( &mode_number, video_mode_ptr, len,
+				 sizeof ( mode_number ) );
+		len += sizeof ( mode_number );
+	} while ( mode_number != VBE_MODE_END );
+
+	/* Allocate and fill mode list */
+	*mode_numbers = malloc ( len );
+	if ( ! *mode_numbers )
+		return -ENOMEM;
+	copy_from_user ( *mode_numbers, video_mode_ptr, 0, len );
+
+	return 0;
+}
+
+/**
+ * Get video mode information
+ *
+ * @v mode_number	Mode number
+ * @ret rc		Return status code
+ */
+static int vesafb_mode_info ( unsigned int mode_number ) {
+	struct vbe_mode_info *mode = &vbe_buf.mode;
+	uint16_t status;
+	int rc;
+
+	/* Get mode information */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x10" )
+			       : "=a" ( status )
+			       : "a" ( VBE_MODE_INFO ),
+				 "c" ( mode_number ),
+				 "D" ( __from_data16 ( mode ) )
+			       : "memory" );
+	if ( ( rc = vesafb_rc ( status ) ) != 0 ) {
+		DBGC ( &vbe_buf, "VESAFB could not get mode %04x information: "
+		       "[%04x] %s\n", mode_number, status, strerror ( rc ) );
+		return rc;
+	}
+	DBGC ( &vbe_buf, "VESAFB mode %04x %dx%d %dbpp(%d:%d:%d:%d) model "
+	       "%02x [x%d]%s%s%s%s%s\n", mode_number, mode->x_resolution,
+	       mode->y_resolution, mode->bits_per_pixel, mode->rsvd_mask_size,
+	       mode->red_mask_size, mode->green_mask_size, mode->blue_mask_size,
+	       mode->memory_model, ( mode->number_of_image_pages + 1 ),
+	       ( ( mode->mode_attributes & VBE_MODE_ATTR_SUPPORTED ) ?
+		 "" : " [unsupported]" ),
+	       ( ( mode->mode_attributes & VBE_MODE_ATTR_TTY ) ?
+		 " [tty]" : "" ),
+	       ( ( mode->mode_attributes & VBE_MODE_ATTR_GRAPHICS ) ?
+		 "" : " [text]" ),
+	       ( ( mode->mode_attributes & VBE_MODE_ATTR_LINEAR ) ?
+		 "" : " [nonlinear]" ),
+	       ( ( mode->mode_attributes & VBE_MODE_ATTR_TRIPLE_BUF ) ?
+		 " [buf]" : "" ) );
+
+	return 0;
+}
+
+/**
+ * Set video mode
+ *
+ * @v mode_number	Mode number
+ * @ret rc		Return status code
+ */
+static int vesafb_set_mode ( unsigned int mode_number ) {
+	struct vbe_mode_info *mode = &vbe_buf.mode;
+	uint16_t status;
+	int rc;
+
+	/* Get mode information */
+	if ( ( rc = vesafb_mode_info ( mode_number ) ) != 0 )
+		return rc;
+
+	/* Record mode parameters */
+	vesafb.start = mode->phys_base_ptr;
+	vesafb.pixel.width = mode->x_resolution;
+	vesafb.pixel.height = mode->y_resolution;
+	vesafb.pixel.len = ( ( mode->bits_per_pixel + 7 ) / 8 );
+	vesafb.pixel.stride = mode->bytes_per_scan_line;
+	DBGC ( &vbe_buf, "VESAFB mode %04x has frame buffer at %08x\n",
+	       mode_number, mode->phys_base_ptr );
+
+	/* Initialise font colours */
+	vesafb.map.red_scale = ( 8 - mode->red_mask_size );
+	vesafb.map.green_scale = ( 8 - mode->green_mask_size );
+	vesafb.map.blue_scale = ( 8 - mode->blue_mask_size );
+	vesafb.map.red_lsb = mode->red_field_position;
+	vesafb.map.green_lsb = mode->green_field_position;
+	vesafb.map.blue_lsb = mode->blue_field_position;
+
+	/* Select this mode */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x10" )
+			       : "=a" ( status )
+			       : "a" ( VBE_SET_MODE ),
+				 "b" ( mode_number ) );
+	if ( ( rc = vesafb_rc ( status ) ) != 0 ) {
+		DBGC ( &vbe_buf, "VESAFB could not set mode %04x: [%04x] %s\n",
+		       mode_number, status, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Select video mode
+ *
+ * @v mode_numbers	Mode number list (terminated with VBE_MODE_END)
+ * @v min_width		Minimum required width (in pixels)
+ * @v min_height	Minimum required height (in pixels)
+ * @v min_bpp		Minimum required colour depth (in bits per pixel)
+ * @ret mode_number	Mode number, or negative error
+ */
+static int vesafb_select_mode ( const uint16_t *mode_numbers,
+				unsigned int min_width, unsigned int min_height,
+				unsigned int min_bpp ) {
+	struct vbe_mode_info *mode = &vbe_buf.mode;
+	int best_mode_number = -ENOENT;
+	unsigned int best_score = INT_MAX;
+	unsigned int score;
+	uint16_t mode_number;
+	int rc;
+
+	/* Find the first suitable mode */
+	while ( ( mode_number = *(mode_numbers++) ) != VBE_MODE_END ) {
+
+		/* Force linear mode variant */
+		mode_number |= VBE_MODE_LINEAR;
+
+		/* Get mode information */
+		if ( ( rc = vesafb_mode_info ( mode_number ) ) != 0 )
+			continue;
+
+		/* Skip unusable modes */
+		if ( ( mode->mode_attributes & ( VBE_MODE_ATTR_SUPPORTED |
+						 VBE_MODE_ATTR_GRAPHICS |
+						 VBE_MODE_ATTR_LINEAR ) ) !=
+		     ( VBE_MODE_ATTR_SUPPORTED | VBE_MODE_ATTR_GRAPHICS |
+		       VBE_MODE_ATTR_LINEAR ) ) {
+			continue;
+		}
+		if ( mode->memory_model != VBE_MODE_MODEL_DIRECT_COLOUR )
+			continue;
+
+		/* Skip modes not meeting the requirements */
+		if ( ( mode->x_resolution < min_width ) ||
+		     ( mode->y_resolution < min_height ) ||
+		     ( mode->bits_per_pixel < min_bpp ) ) {
+			continue;
+		}
+
+		/* Select this mode if it has the best (i.e. lowest)
+		 * score.  We choose the scoring system to favour
+		 * modes close to the specified width and height;
+		 * within modes of the same width and height we prefer
+		 * a higher colour depth.
+		 */
+		score = ( ( mode->x_resolution * mode->y_resolution ) -
+			  mode->bits_per_pixel );
+		if ( score < best_score ) {
+			best_mode_number = mode_number;
+			best_score = score;
+		}
+	}
+
+	if ( best_mode_number >= 0 ) {
+		DBGC ( &vbe_buf, "VESAFB selected mode %04x\n",
+		       best_mode_number );
+	} else {
+		DBGC ( &vbe_buf, "VESAFB found no suitable mode\n" );
+	}
+
+	return best_mode_number;
+}
+
+/**
+ * Restore video mode
+ *
+ */
+static void vesafb_restore ( void ) {
+	uint32_t discard_a;
+
+	/* Restore saved VGA mode */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x10" )
+			       : "=a" ( discard_a )
+			       : "a" ( VBE_SET_VGA_MODE | vesafb.saved_mode ) );
+	DBGC ( &vbe_buf, "VESAFB restored VGA mode %#02x\n",
+	       vesafb.saved_mode );
+}
+
+/**
+ * Initialise VESA frame buffer
+ *
+ * @v config		Console configuration, or NULL to reset
+ * @ret rc		Return status code
+ */
+static int vesafb_init ( struct console_configuration *config ) {
+	uint32_t discard_b;
+	uint16_t *mode_numbers;
+	unsigned int xgap;
+	unsigned int ygap;
+	unsigned int left;
+	unsigned int right;
+	unsigned int top;
+	unsigned int bottom;
+	int mode_number;
+	int rc;
+
+	/* Record current VGA mode */
+	__asm__ __volatile__ ( REAL_CODE ( "int $0x10" )
+			       : "=a" ( vesafb.saved_mode ), "=b" ( discard_b )
+			       : "a" ( VBE_GET_VGA_MODE ) );
+	DBGC ( &vbe_buf, "VESAFB saved VGA mode %#02x\n", vesafb.saved_mode );
+
+	/* Get VESA mode list */
+	if ( ( rc = vesafb_mode_list ( &mode_numbers ) ) != 0 )
+		goto err_mode_list;
+
+	/* Select mode */
+	if ( ( mode_number = vesafb_select_mode ( mode_numbers, config->width,
+						  config->height,
+						  config->depth ) ) < 0 ) {
+		rc = mode_number;
+		goto err_select_mode;
+	}
+
+	/* Set mode */
+	if ( ( rc = vesafb_set_mode ( mode_number ) ) != 0 )
+		goto err_set_mode;
+
+	/* Calculate margin.  If the actual screen size is larger than
+	 * the requested screen size, then update the margins so that
+	 * the margin remains relative to the requested screen size.
+	 * (As an exception, if a zero margin was specified then treat
+	 * this as meaning "expand to edge of actual screen".)
+	 */
+	xgap = ( vesafb.pixel.width - config->width );
+	ygap = ( vesafb.pixel.height - config->height );
+	left = ( xgap / 2 );
+	right = ( xgap - left );
+	top = ( ygap / 2 );
+	bottom = ( ygap - top );
+	vesafb.margin.left = ( config->left + ( config->left ? left : 0 ) );
+	vesafb.margin.right = ( config->right + ( config->right ? right : 0 ) );
+	vesafb.margin.top = ( config->top + ( config->top ? top : 0 ) );
+	vesafb.margin.bottom =
+		( config->bottom + ( config->bottom ? bottom : 0 ) );
+
+	/* Get font data */
+	vesafb_font();
+
+	/* Initialise frame buffer console */
+	if ( ( rc = fbcon_init ( &vesafb.fbcon, phys_to_user ( vesafb.start ),
+				 &vesafb.pixel, &vesafb.margin, &vesafb.map,
+				 &vesafb.font, config->pixbuf ) ) != 0 )
+		goto err_fbcon_init;
+
+	free ( mode_numbers );
+	return 0;
+
+	fbcon_fini ( &vesafb.fbcon );
+ err_fbcon_init:
+ err_set_mode:
+	vesafb_restore();
+ err_select_mode:
+	free ( mode_numbers );
+ err_mode_list:
+	return rc;
+}
+
+/**
+ * Finalise VESA frame buffer
+ *
+ */
+static void vesafb_fini ( void ) {
+
+	/* Finalise frame buffer console */
+	fbcon_fini ( &vesafb.fbcon );
+
+	/* Restore saved VGA mode */
+	vesafb_restore();
+}
+
+/**
+ * Print a character to current cursor position
+ *
+ * @v character		Character
+ */
+static void vesafb_putchar ( int character ) {
+
+	fbcon_putchar ( &vesafb.fbcon, character );
+}
+
+/**
+ * Configure console
+ *
+ * @v config		Console configuration, or NULL to reset
+ * @ret rc		Return status code
+ */
+static int vesafb_configure ( struct console_configuration *config ) {
+	int rc;
+
+	/* Reset console, if applicable */
+	if ( ! vesafb_console.disabled ) {
+		vesafb_fini();
+		bios_console.disabled &= ~CONSOLE_DISABLED_OUTPUT;
+		ansicol_reset_magic();
+	}
+	vesafb_console.disabled = CONSOLE_DISABLED;
+
+	/* Do nothing more unless we have a usable configuration */
+	if ( ( config == NULL ) ||
+	     ( config->width == 0 ) || ( config->height == 0 ) ) {
+		return 0;
+	}
+
+	/* Initialise VESA frame buffer */
+	if ( ( rc = vesafb_init ( config ) ) != 0 )
+		return rc;
+
+	/* Mark console as enabled */
+	vesafb_console.disabled = 0;
+	bios_console.disabled |= CONSOLE_DISABLED_OUTPUT;
+
+	/* Set magic colour to transparent if we have a background picture */
+	if ( config->pixbuf )
+		ansicol_set_magic_transparent();
+
+	return 0;
+}
+
+/** VESA frame buffer console driver */
+struct console_driver vesafb_console __console_driver = {
+	.usage = CONSOLE_VESAFB,
+	.putchar = vesafb_putchar,
+	.configure = vesafb_configure,
+	.disabled = CONSOLE_DISABLED,
+};