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qemu/blockdev.c
Ryan Harper 9063f81415 Implement drive_del to decouple block removal from device removal 
Currently device hotplug removal code is tied to device removal via
ACPI.  All pci devices that are removable via device_del() require the
guest to respond to the request.  In some cases the guest may not
respond leaving the device still accessible to the guest.  The management
layer doesn't currently have a reliable way to revoke access to host
resource in the presence of an uncooperative guest.

This patch implements a new monitor command, drive_del, which
provides an explicit command to revoke access to a host block device.

drive_del first quiesces the block device (qemu_aio_flush;
bdrv_flush() and bdrv_close()).  This prevents further IO from being
submitted against the host device.  Finally, drive_del cleans up
pointers between the drive object (host resource) and the device
object (guest resource).

Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-11-24 17:30:19 +01:00

638 lines
17 KiB
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/*
* QEMU host block devices
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "block.h"
#include "blockdev.h"
#include "monitor.h"
#include "qerror.h"
#include "qemu-option.h"
#include "qemu-config.h"
#include "sysemu.h"
#include "hw/qdev.h"
#include "block_int.h"
static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
/*
* We automatically delete the drive when a device using it gets
* unplugged. Questionable feature, but we can't just drop it.
* Device models call blockdev_mark_auto_del() to schedule the
* automatic deletion, and generic qdev code calls blockdev_auto_del()
* when deletion is actually safe.
*/
void blockdev_mark_auto_del(BlockDriverState *bs)
{
DriveInfo *dinfo = drive_get_by_blockdev(bs);
dinfo->auto_del = 1;
}
void blockdev_auto_del(BlockDriverState *bs)
{
DriveInfo *dinfo = drive_get_by_blockdev(bs);
if (dinfo->auto_del) {
drive_uninit(dinfo);
}
}
QemuOpts *drive_add(const char *file, const char *fmt, ...)
{
va_list ap;
char optstr[1024];
QemuOpts *opts;
va_start(ap, fmt);
vsnprintf(optstr, sizeof(optstr), fmt, ap);
va_end(ap);
opts = qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
if (!opts) {
return NULL;
}
if (file)
qemu_opt_set(opts, "file", file);
return opts;
}
DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
{
DriveInfo *dinfo;
/* seek interface, bus and unit */
QTAILQ_FOREACH(dinfo, &drives, next) {
if (dinfo->type == type &&
dinfo->bus == bus &&
dinfo->unit == unit)
return dinfo;
}
return NULL;
}
int drive_get_max_bus(BlockInterfaceType type)
{
int max_bus;
DriveInfo *dinfo;
max_bus = -1;
QTAILQ_FOREACH(dinfo, &drives, next) {
if(dinfo->type == type &&
dinfo->bus > max_bus)
max_bus = dinfo->bus;
}
return max_bus;
}
DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
{
DriveInfo *dinfo;
QTAILQ_FOREACH(dinfo, &drives, next) {
if (dinfo->bdrv == bs) {
return dinfo;
}
}
return NULL;
}
static void bdrv_format_print(void *opaque, const char *name)
{
fprintf(stderr, " %s", name);
}
void drive_uninit(DriveInfo *dinfo)
{
qemu_opts_del(dinfo->opts);
bdrv_delete(dinfo->bdrv);
QTAILQ_REMOVE(&drives, dinfo, next);
qemu_free(dinfo);
}
static int parse_block_error_action(const char *buf, int is_read)
{
if (!strcmp(buf, "ignore")) {
return BLOCK_ERR_IGNORE;
} else if (!is_read && !strcmp(buf, "enospc")) {
return BLOCK_ERR_STOP_ENOSPC;
} else if (!strcmp(buf, "stop")) {
return BLOCK_ERR_STOP_ANY;
} else if (!strcmp(buf, "report")) {
return BLOCK_ERR_REPORT;
} else {
fprintf(stderr, "qemu: '%s' invalid %s error action\n",
buf, is_read ? "read" : "write");
return -1;
}
}
DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
{
const char *buf;
const char *file = NULL;
char devname[128];
const char *serial;
const char *mediastr = "";
BlockInterfaceType type;
enum { MEDIA_DISK, MEDIA_CDROM } media;
int bus_id, unit_id;
int cyls, heads, secs, translation;
BlockDriver *drv = NULL;
int max_devs;
int index;
int ro = 0;
int bdrv_flags = 0;
int on_read_error, on_write_error;
const char *devaddr;
DriveInfo *dinfo;
int snapshot = 0;
int ret;
*fatal_error = 1;
translation = BIOS_ATA_TRANSLATION_AUTO;
if (default_to_scsi) {
type = IF_SCSI;
max_devs = MAX_SCSI_DEVS;
pstrcpy(devname, sizeof(devname), "scsi");
} else {
type = IF_IDE;
max_devs = MAX_IDE_DEVS;
pstrcpy(devname, sizeof(devname), "ide");
}
media = MEDIA_DISK;
/* extract parameters */
bus_id = qemu_opt_get_number(opts, "bus", 0);
unit_id = qemu_opt_get_number(opts, "unit", -1);
index = qemu_opt_get_number(opts, "index", -1);
cyls = qemu_opt_get_number(opts, "cyls", 0);
heads = qemu_opt_get_number(opts, "heads", 0);
secs = qemu_opt_get_number(opts, "secs", 0);
snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
ro = qemu_opt_get_bool(opts, "readonly", 0);
file = qemu_opt_get(opts, "file");
serial = qemu_opt_get(opts, "serial");
if ((buf = qemu_opt_get(opts, "if")) != NULL) {
pstrcpy(devname, sizeof(devname), buf);
if (!strcmp(buf, "ide")) {
type = IF_IDE;
max_devs = MAX_IDE_DEVS;
} else if (!strcmp(buf, "scsi")) {
type = IF_SCSI;
max_devs = MAX_SCSI_DEVS;
} else if (!strcmp(buf, "floppy")) {
type = IF_FLOPPY;
max_devs = 0;
} else if (!strcmp(buf, "pflash")) {
type = IF_PFLASH;
max_devs = 0;
} else if (!strcmp(buf, "mtd")) {
type = IF_MTD;
max_devs = 0;
} else if (!strcmp(buf, "sd")) {
type = IF_SD;
max_devs = 0;
} else if (!strcmp(buf, "virtio")) {
type = IF_VIRTIO;
max_devs = 0;
} else if (!strcmp(buf, "xen")) {
type = IF_XEN;
max_devs = 0;
} else if (!strcmp(buf, "none")) {
type = IF_NONE;
max_devs = 0;
} else {
fprintf(stderr, "qemu: unsupported bus type '%s'\n", buf);
return NULL;
}
}
if (cyls || heads || secs) {
if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
fprintf(stderr, "qemu: '%s' invalid physical cyls number\n", buf);
return NULL;
}
if (heads < 1 || (type == IF_IDE && heads > 16)) {
fprintf(stderr, "qemu: '%s' invalid physical heads number\n", buf);
return NULL;
}
if (secs < 1 || (type == IF_IDE && secs > 63)) {
fprintf(stderr, "qemu: '%s' invalid physical secs number\n", buf);
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
if (!cyls) {
fprintf(stderr,
"qemu: '%s' trans must be used with cyls,heads and secs\n",
buf);
return NULL;
}
if (!strcmp(buf, "none"))
translation = BIOS_ATA_TRANSLATION_NONE;
else if (!strcmp(buf, "lba"))
translation = BIOS_ATA_TRANSLATION_LBA;
else if (!strcmp(buf, "auto"))
translation = BIOS_ATA_TRANSLATION_AUTO;
else {
fprintf(stderr, "qemu: '%s' invalid translation type\n", buf);
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "media")) != NULL) {
if (!strcmp(buf, "disk")) {
media = MEDIA_DISK;
} else if (!strcmp(buf, "cdrom")) {
if (cyls || secs || heads) {
fprintf(stderr,
"qemu: '%s' invalid physical CHS format\n", buf);
return NULL;
}
media = MEDIA_CDROM;
} else {
fprintf(stderr, "qemu: '%s' invalid media\n", buf);
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
bdrv_flags |= BDRV_O_NOCACHE;
} else if (!strcmp(buf, "writeback")) {
bdrv_flags |= BDRV_O_CACHE_WB;
} else if (!strcmp(buf, "unsafe")) {
bdrv_flags |= BDRV_O_CACHE_WB;
bdrv_flags |= BDRV_O_NO_FLUSH;
} else if (!strcmp(buf, "writethrough")) {
/* this is the default */
} else {
fprintf(stderr, "qemu: invalid cache option\n");
return NULL;
}
}
#ifdef CONFIG_LINUX_AIO
if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
if (!strcmp(buf, "native")) {
bdrv_flags |= BDRV_O_NATIVE_AIO;
} else if (!strcmp(buf, "threads")) {
/* this is the default */
} else {
fprintf(stderr, "qemu: invalid aio option\n");
return NULL;
}
}
#endif
if ((buf = qemu_opt_get(opts, "format")) != NULL) {
if (strcmp(buf, "?") == 0) {
fprintf(stderr, "qemu: Supported formats:");
bdrv_iterate_format(bdrv_format_print, NULL);
fprintf(stderr, "\n");
return NULL;
}
drv = bdrv_find_whitelisted_format(buf);
if (!drv) {
fprintf(stderr, "qemu: '%s' invalid format\n", buf);
return NULL;
}
}
on_write_error = BLOCK_ERR_STOP_ENOSPC;
if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
fprintf(stderr, "werror is not supported by this format\n");
return NULL;
}
on_write_error = parse_block_error_action(buf, 0);
if (on_write_error < 0) {
return NULL;
}
}
on_read_error = BLOCK_ERR_REPORT;
if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
fprintf(stderr, "rerror is not supported by this format\n");
return NULL;
}
on_read_error = parse_block_error_action(buf, 1);
if (on_read_error < 0) {
return NULL;
}
}
if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
if (type != IF_VIRTIO) {
fprintf(stderr, "addr is not supported\n");
return NULL;
}
}
/* compute bus and unit according index */
if (index != -1) {
if (bus_id != 0 || unit_id != -1) {
fprintf(stderr,
"qemu: index cannot be used with bus and unit\n");
return NULL;
}
if (max_devs == 0)
{
unit_id = index;
bus_id = 0;
} else {
unit_id = index % max_devs;
bus_id = index / max_devs;
}
}
/* if user doesn't specify a unit_id,
* try to find the first free
*/
if (unit_id == -1) {
unit_id = 0;
while (drive_get(type, bus_id, unit_id) != NULL) {
unit_id++;
if (max_devs && unit_id >= max_devs) {
unit_id -= max_devs;
bus_id++;
}
}
}
/* check unit id */
if (max_devs && unit_id >= max_devs) {
fprintf(stderr, "qemu: unit %d too big (max is %d)\n",
unit_id, max_devs - 1);
return NULL;
}
/*
* ignore multiple definitions
*/
if (drive_get(type, bus_id, unit_id) != NULL) {
*fatal_error = 0;
return NULL;
}
/* init */
dinfo = qemu_mallocz(sizeof(*dinfo));
if ((buf = qemu_opts_id(opts)) != NULL) {
dinfo->id = qemu_strdup(buf);
} else {
/* no id supplied -> create one */
dinfo->id = qemu_mallocz(32);
if (type == IF_IDE || type == IF_SCSI)
mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
if (max_devs)
snprintf(dinfo->id, 32, "%s%i%s%i",
devname, bus_id, mediastr, unit_id);
else
snprintf(dinfo->id, 32, "%s%s%i",
devname, mediastr, unit_id);
}
dinfo->bdrv = bdrv_new(dinfo->id);
dinfo->devaddr = devaddr;
dinfo->type = type;
dinfo->bus = bus_id;
dinfo->unit = unit_id;
dinfo->opts = opts;
if (serial)
strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
QTAILQ_INSERT_TAIL(&drives, dinfo, next);
bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
switch(type) {
case IF_IDE:
case IF_SCSI:
case IF_XEN:
case IF_NONE:
switch(media) {
case MEDIA_DISK:
if (cyls != 0) {
bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
bdrv_set_translation_hint(dinfo->bdrv, translation);
}
break;
case MEDIA_CDROM:
bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_CDROM);
break;
}
break;
case IF_SD:
/* FIXME: This isn't really a floppy, but it's a reasonable
approximation. */
case IF_FLOPPY:
bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_FLOPPY);
break;
case IF_PFLASH:
case IF_MTD:
break;
case IF_VIRTIO:
/* add virtio block device */
opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
qemu_opt_set(opts, "driver", "virtio-blk-pci");
qemu_opt_set(opts, "drive", dinfo->id);
if (devaddr)
qemu_opt_set(opts, "addr", devaddr);
break;
case IF_COUNT:
abort();
}
if (!file || !*file) {
*fatal_error = 0;
return NULL;
}
if (snapshot) {
/* always use cache=unsafe with snapshot */
bdrv_flags &= ~BDRV_O_CACHE_MASK;
bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
}
if (media == MEDIA_CDROM) {
/* CDROM is fine for any interface, don't check. */
ro = 1;
} else if (ro == 1) {
if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
fprintf(stderr, "qemu: readonly flag not supported for drive with this interface\n");
return NULL;
}
}
bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
if (ret < 0) {
fprintf(stderr, "qemu: could not open disk image %s: %s\n",
file, strerror(-ret));
return NULL;
}
if (bdrv_key_required(dinfo->bdrv))
autostart = 0;
*fatal_error = 0;
return dinfo;
}
void do_commit(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");
BlockDriverState *bs;
if (!strcmp(device, "all")) {
bdrv_commit_all();
} else {
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
return;
}
bdrv_commit(bs);
}
}
static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
{
if (!force) {
if (!bdrv_is_removable(bs)) {
qerror_report(QERR_DEVICE_NOT_REMOVABLE,
bdrv_get_device_name(bs));
return -1;
}
if (bdrv_is_locked(bs)) {
qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
return -1;
}
}
bdrv_close(bs);
return 0;
}
int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
BlockDriverState *bs;
int force = qdict_get_try_bool(qdict, "force", 0);
const char *filename = qdict_get_str(qdict, "device");
bs = bdrv_find(filename);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, filename);
return -1;
}
return eject_device(mon, bs, force);
}
int do_block_set_passwd(Monitor *mon, const QDict *qdict,
QObject **ret_data)
{
BlockDriverState *bs;
int err;
bs = bdrv_find(qdict_get_str(qdict, "device"));
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
return -1;
}
err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
if (err == -EINVAL) {
qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
return -1;
} else if (err < 0) {
qerror_report(QERR_INVALID_PASSWORD);
return -1;
}
return 0;
}
int do_change_block(Monitor *mon, const char *device,
const char *filename, const char *fmt)
{
BlockDriverState *bs;
BlockDriver *drv = NULL;
int bdrv_flags;
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
return -1;
}
if (fmt) {
drv = bdrv_find_whitelisted_format(fmt);
if (!drv) {
qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
return -1;
}
}
if (eject_device(mon, bs, 0) < 0) {
return -1;
}
bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
qerror_report(QERR_OPEN_FILE_FAILED, filename);
return -1;
}
return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
}
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
const char *id = qdict_get_str(qdict, "id");
BlockDriverState *bs;
BlockDriverState **ptr;
Property *prop;
bs = bdrv_find(id);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, id);
return -1;
}
/* quiesce block driver; prevent further io */
qemu_aio_flush();
bdrv_flush(bs);
bdrv_close(bs);
/* clean up guest state from pointing to host resource by
* finding and removing DeviceState "drive" property */
for (prop = bs->peer->info->props; prop && prop->name; prop++) {
if (prop->info->type == PROP_TYPE_DRIVE) {
ptr = qdev_get_prop_ptr(bs->peer, prop);
if ((*ptr) == bs) {
bdrv_detach(bs, bs->peer);
*ptr = NULL;
break;
}
}
}
/* clean up host side */
drive_uninit(drive_get_by_blockdev(bs));
return 0;
}
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