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qemu/hw/block/xen-block.c
David Woodhouse 6f7997e004 hw/xen: clean up xen_block_find_free_vdev() to avoid Coverity false positive 
Coverity couldn't see that nr_existing was always going to be zero when
qemu_xen_xs_directory() returned NULL in the ENOENT case (CID 1523906).

Perhaps more to the point, neither could Peter at first glance. Improve
the code to hopefully make it clearer to Coverity and human reviewers
alike.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-11-21 11:45:06 +00:00

1177 lines
32 KiB
C
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/*
* Copyright (c) 2018 Citrix Systems Inc.
*
* 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 "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-block-core.h"
#include "qapi/qapi-commands-qom.h"
#include "qapi/qapi-visit-block-core.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/visitor.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qom/object_interfaces.h"
#include "hw/block/xen_blkif.h"
#include "hw/qdev-properties.h"
#include "hw/xen/xen-block.h"
#include "hw/xen/xen-backend.h"
#include "sysemu/blockdev.h"
#include "sysemu/block-backend.h"
#include "sysemu/iothread.h"
#include "dataplane/xen-block.h"
#include "hw/xen/interface/io/xs_wire.h"
#include "trace.h"
#define XVDA_MAJOR 202
#define XVDQ_MAJOR (1 << 20)
#define XVDBGQCV_MAJOR ((1 << 21) - 1)
#define HDA_MAJOR 3
#define HDC_MAJOR 22
#define SDA_MAJOR 8
static int vdev_to_diskno(unsigned int vdev_nr)
{
switch (vdev_nr >> 8) {
case XVDA_MAJOR:
case SDA_MAJOR:
return (vdev_nr >> 4) & 0x15;
case HDA_MAJOR:
return (vdev_nr >> 6) & 1;
case HDC_MAJOR:
return ((vdev_nr >> 6) & 1) + 2;
case XVDQ_MAJOR ... XVDBGQCV_MAJOR:
return (vdev_nr >> 8) & 0xfffff;
default:
return -1;
}
}
#define MAX_AUTO_VDEV 4096
/*
* Find a free device name in the xvda → xvdfan range and set it in
* blockdev->props.vdev. Our definition of "free" is that there must
* be no other disk or partition with the same disk number.
*
* You are technically permitted to have all of hda, hda1, sda, sda1,
* xvda and xvda1 as *separate* PV block devices with separate backing
* stores. That doesn't make it a good idea. This code will skip xvda
* if *any* of those "conflicting" devices already exists.
*
* The limit of xvdfan (disk 4095) is fairly arbitrary just to avoid a
* stupidly sized bitmap, but Linux as of v6.6 doesn't support anything
* higher than that anyway.
*/
static bool xen_block_find_free_vdev(XenBlockDevice *blockdev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(blockdev)));
unsigned long used_devs[BITS_TO_LONGS(MAX_AUTO_VDEV)];
XenBlockVdev *vdev = &blockdev->props.vdev;
char fe_path[XENSTORE_ABS_PATH_MAX + 1];
char **existing_frontends;
unsigned int nr_existing = 0;
unsigned int vdev_nr;
int i, disk = 0;
snprintf(fe_path, sizeof(fe_path), "/local/domain/%u/device/vbd",
blockdev->xendev.frontend_id);
existing_frontends = qemu_xen_xs_directory(xenbus->xsh, XBT_NULL, fe_path,
&nr_existing);
if (!existing_frontends) {
if (errno == ENOENT) {
/*
* If the frontend directory doesn't exist because there are
* no existing vbd devices, that's fine. Just ensure that we
* don't dereference the NULL existing_frontends pointer, by
* checking that nr_existing is zero so the loop below is not
* entered.
*
* In fact this is redundant since nr_existing is initialized
* to zero, but setting it again here makes it abundantly clear
* to Coverity, and to the human reader who doesn't know the
* semantics of qemu_xen_xs_directory() off the top of their
* head.
*/
nr_existing = 0;
} else {
/* All other errors accessing the frontend directory are fatal. */
error_setg_errno(errp, errno, "cannot read %s", fe_path);
return false;
}
}
memset(used_devs, 0, sizeof(used_devs));
for (i = 0; i < nr_existing; i++) {
if (qemu_strtoui(existing_frontends[i], NULL, 10, &vdev_nr)) {
free(existing_frontends[i]);
continue;
}
free(existing_frontends[i]);
disk = vdev_to_diskno(vdev_nr);
if (disk < 0 || disk >= MAX_AUTO_VDEV) {
continue;
}
set_bit(disk, used_devs);
}
free(existing_frontends);
disk = find_first_zero_bit(used_devs, MAX_AUTO_VDEV);
if (disk == MAX_AUTO_VDEV) {
error_setg(errp, "cannot find device vdev for block device");
return false;
}
vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
vdev->partition = 0;
vdev->disk = disk;
if (disk < (1 << 4)) {
vdev->number = (XVDA_MAJOR << 8) | (disk << 4);
} else {
vdev->number = (XVDQ_MAJOR << 8) | (disk << 8);
}
return true;
}
static char *xen_block_get_name(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID &&
!xen_block_find_free_vdev(blockdev, errp)) {
return NULL;
}
return g_strdup_printf("%lu", vdev->number);
}
static void xen_block_disconnect(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
xen_block_dataplane_stop(blockdev->dataplane);
}
static void xen_block_connect(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
unsigned int feature_large_sector_size;
unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
char *str;
trace_xen_block_connect(type, vdev->disk, vdev->partition);
if (xen_device_frontend_scanf(xendev, "feature-large-sector-size", "%u",
&feature_large_sector_size) != 1) {
feature_large_sector_size = 0;
}
if (feature_large_sector_size != 1 &&
conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
error_setg(errp, "logical_block_size != %u not supported by frontend",
XEN_BLKIF_SECTOR_SIZE);
return;
}
if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
&order) != 1) {
nr_ring_ref = 1;
ring_ref = g_new(unsigned int, nr_ring_ref);
if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
&ring_ref[0]) != 1) {
error_setg(errp, "failed to read ring-ref");
g_free(ring_ref);
return;
}
} else if (qemu_xen_gnttab_can_map_multi() &&
order <= blockdev->props.max_ring_page_order) {
unsigned int i;
nr_ring_ref = 1 << order;
ring_ref = g_new(unsigned int, nr_ring_ref);
for (i = 0; i < nr_ring_ref; i++) {
const char *key = g_strdup_printf("ring-ref%u", i);
if (xen_device_frontend_scanf(xendev, key, "%u",
&ring_ref[i]) != 1) {
error_setg(errp, "failed to read %s", key);
g_free((gpointer)key);
g_free(ring_ref);
return;
}
g_free((gpointer)key);
}
} else {
error_setg(errp, "invalid ring-page-order (%d)", order);
return;
}
if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
&event_channel) != 1) {
error_setg(errp, "failed to read event-channel");
g_free(ring_ref);
return;
}
if (xen_device_frontend_scanf(xendev, "protocol", "%ms", &str) != 1) {
/* x86 defaults to the 32-bit protocol even for 64-bit guests. */
if (object_dynamic_cast(OBJECT(qdev_get_machine()), "x86-machine")) {
protocol = BLKIF_PROTOCOL_X86_32;
} else {
protocol = BLKIF_PROTOCOL_NATIVE;
}
} else {
if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
protocol = BLKIF_PROTOCOL_X86_32;
} else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
protocol = BLKIF_PROTOCOL_X86_64;
} else {
protocol = BLKIF_PROTOCOL_NATIVE;
}
free(str);
}
xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
event_channel, protocol, errp);
g_free(ring_ref);
}
static void xen_block_unrealize(XenDevice *xendev)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockDeviceClass *blockdev_class =
XEN_BLOCK_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
return;
}
trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
/* Disconnect from the frontend in case this has not already happened */
xen_block_disconnect(xendev, NULL);
xen_block_dataplane_destroy(blockdev->dataplane);
blockdev->dataplane = NULL;
if (blockdev_class->unrealize) {
blockdev_class->unrealize(blockdev);
}
}
static void xen_block_set_size(XenBlockDevice *blockdev)
{
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
XenDevice *xendev = XEN_DEVICE(blockdev);
trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
}
static void xen_block_resize_cb(void *opaque)
{
XenBlockDevice *blockdev = opaque;
XenDevice *xendev = XEN_DEVICE(blockdev);
enum xenbus_state state = xen_device_backend_get_state(xendev);
xen_block_set_size(blockdev);
/*
* Mimic the behaviour of Linux xen-blkback and re-write the state
* to trigger the frontend watch.
*/
xen_device_backend_printf(xendev, "state", "%u", state);
}
/* Suspend request handling */
static void xen_block_drained_begin(void *opaque)
{
XenBlockDevice *blockdev = opaque;
xen_block_dataplane_detach(blockdev->dataplane);
}
/* Resume request handling */
static void xen_block_drained_end(void *opaque)
{
XenBlockDevice *blockdev = opaque;
xen_block_dataplane_attach(blockdev->dataplane);
}
static const BlockDevOps xen_block_dev_ops = {
.resize_cb = xen_block_resize_cb,
.drained_begin = xen_block_drained_begin,
.drained_end = xen_block_drained_end,
};
static void xen_block_realize(XenDevice *xendev, Error **errp)
{
ERRP_GUARD();
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockDeviceClass *blockdev_class =
XEN_BLOCK_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
BlockBackend *blk = conf->blk;
if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
error_setg(errp, "vdev property not set");
return;
}
trace_xen_block_realize(type, vdev->disk, vdev->partition);
if (blockdev_class->realize) {
blockdev_class->realize(blockdev, errp);
if (*errp) {
return;
}
}
/*
* The blkif protocol does not deal with removable media, so it must
* always be present, even for CDRom devices.
*/
assert(blk);
if (!blk_is_inserted(blk)) {
error_setg(errp, "device needs media, but drive is empty");
return;
}
if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
true, errp)) {
return;
}
if (!(blockdev->info & VDISK_CDROM) &&
!blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
return;
}
if (!blkconf_blocksizes(conf, errp)) {
return;
}
if (conf->discard_granularity == -1) {
conf->discard_granularity = conf->physical_block_size;
}
if (blk_get_flags(blk) & BDRV_O_UNMAP) {
xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
xen_device_backend_printf(xendev, "discard-granularity", "%u",
conf->discard_granularity);
xen_device_backend_printf(xendev, "discard-alignment", "%u", 0);
}
xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
if (qemu_xen_gnttab_can_map_multi()) {
xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
blockdev->props.max_ring_page_order);
}
xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
xen_device_frontend_printf(xendev, "virtual-device", "%lu",
vdev->number);
xen_device_frontend_printf(xendev, "device-type", "%s",
blockdev->device_type);
xen_device_backend_printf(xendev, "sector-size", "%u",
conf->logical_block_size);
xen_block_set_size(blockdev);
blockdev->dataplane =
xen_block_dataplane_create(xendev, blk, conf->logical_block_size,
blockdev->props.iothread);
blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
}
static void xen_block_frontend_changed(XenDevice *xendev,
enum xenbus_state frontend_state,
Error **errp)
{
ERRP_GUARD();
enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
switch (frontend_state) {
case XenbusStateInitialised:
case XenbusStateConnected:
if (backend_state == XenbusStateConnected) {
break;
}
xen_block_disconnect(xendev, errp);
if (*errp) {
break;
}
xen_block_connect(xendev, errp);
if (*errp) {
break;
}
xen_device_backend_set_state(xendev, XenbusStateConnected);
break;
case XenbusStateClosing:
xen_device_backend_set_state(xendev, XenbusStateClosing);
break;
case XenbusStateClosed:
case XenbusStateUnknown:
xen_block_disconnect(xendev, errp);
if (*errp) {
break;
}
xen_device_backend_set_state(xendev, XenbusStateClosed);
break;
default:
break;
}
}
static char *disk_to_vbd_name(unsigned int disk)
{
char *name, *prefix = (disk >= 26) ?
disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
g_free(prefix);
return name;
}
static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
Property *prop = opaque;
XenBlockVdev *vdev = object_field_prop_ptr(obj, prop);
char *str;
switch (vdev->type) {
case XEN_BLOCK_VDEV_TYPE_DP:
str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
break;
case XEN_BLOCK_VDEV_TYPE_XVD:
case XEN_BLOCK_VDEV_TYPE_HD:
case XEN_BLOCK_VDEV_TYPE_SD: {
char *vbd_name = disk_to_vbd_name(vdev->disk);
str = g_strdup_printf("%s%s%lu",
(vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
"xvd" :
(vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
"hd" :
"sd",
vbd_name, vdev->partition);
g_free(vbd_name);
break;
}
default:
error_setg(errp, "invalid vdev type");
return;
}
visit_type_str(v, name, &str, errp);
g_free(str);
}
static int vbd_name_to_disk(const char *name, const char **endp,
unsigned long *disk)
{
unsigned int n = 0;
while (*name != '\0') {
if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
break;
}
n *= 26;
n += *name++ - 'a' + 1;
}
*endp = name;
if (!n) {
return -1;
}
*disk = n - 1;
return 0;
}
static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
Property *prop = opaque;
XenBlockVdev *vdev = object_field_prop_ptr(obj, prop);
char *str, *p;
const char *end;
if (!visit_type_str(v, name, &str, errp)) {
return;
}
p = strchr(str, 'd');
if (!p) {
goto invalid;
}
*p++ = '\0';
if (*str == '\0') {
vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
} else if (strcmp(str, "xv") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
} else if (strcmp(str, "h") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
} else if (strcmp(str, "s") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
} else {
goto invalid;
}
if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
goto invalid;
}
if (*end == 'p') {
if (*(++end) == '\0') {
goto invalid;
}
}
} else {
if (vbd_name_to_disk(p, &end, &vdev->disk)) {
goto invalid;
}
}
if (*end != '\0') {
p = (char *)end;
if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
goto invalid;
}
if (*end != '\0') {
goto invalid;
}
} else {
vdev->partition = 0;
}
switch (vdev->type) {
case XEN_BLOCK_VDEV_TYPE_DP:
case XEN_BLOCK_VDEV_TYPE_XVD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
vdev->number = (XVDA_MAJOR << 8) | (vdev->disk << 4) |
vdev->partition;
} else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
vdev->number = (XVDQ_MAJOR << 8) | (vdev->disk << 8) |
vdev->partition;
} else {
goto invalid;
}
break;
case XEN_BLOCK_VDEV_TYPE_HD:
if ((vdev->disk == 0 || vdev->disk == 1) &&
vdev->partition < (1 << 6)) {
vdev->number = (HDA_MAJOR << 8) | (vdev->disk << 6) |
vdev->partition;
} else if ((vdev->disk == 2 || vdev->disk == 3) &&
vdev->partition < (1 << 6)) {
vdev->number = (HDC_MAJOR << 8) | ((vdev->disk - 2) << 6) |
vdev->partition;
} else {
goto invalid;
}
break;
case XEN_BLOCK_VDEV_TYPE_SD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
vdev->number = (SDA_MAJOR << 8) | (vdev->disk << 4) |
vdev->partition;
} else {
goto invalid;
}
break;
default:
goto invalid;
}
g_free(str);
return;
invalid:
error_setg(errp, "invalid virtual disk specifier");
vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
g_free(str);
}
/*
* This property deals with 'vdev' names adhering to the Xen VBD naming
* scheme described in:
*
* https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
*/
const PropertyInfo xen_block_prop_vdev = {
.name = "str",
.description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
.get = xen_block_get_vdev,
.set = xen_block_set_vdev,
};
static Property xen_block_props[] = {
DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
xen_block_prop_vdev, XenBlockVdev),
DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
props.max_ring_page_order, 4),
DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
TYPE_IOTHREAD, IOThread *),
DEFINE_PROP_END_OF_LIST()
};
static void xen_block_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
xendev_class->backend = "qdisk";
xendev_class->device = "vbd";
xendev_class->get_name = xen_block_get_name;
xendev_class->realize = xen_block_realize;
xendev_class->frontend_changed = xen_block_frontend_changed;
xendev_class->unrealize = xen_block_unrealize;
device_class_set_props(dev_class, xen_block_props);
}
static const TypeInfo xen_block_type_info = {
.name = TYPE_XEN_BLOCK_DEVICE,
.parent = TYPE_XEN_DEVICE,
.instance_size = sizeof(XenBlockDevice),
.abstract = true,
.class_size = sizeof(XenBlockDeviceClass),
.class_init = xen_block_class_init,
};
static void xen_disk_unrealize(XenBlockDevice *blockdev)
{
trace_xen_disk_unrealize();
}
static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
{
BlockConf *conf = &blockdev->props.conf;
trace_xen_disk_realize();
blockdev->device_type = "disk";
if (!conf->blk) {
error_setg(errp, "drive property not set");
return;
}
blockdev->info = blk_supports_write_perm(conf->blk) ? 0 : VDISK_READONLY;
}
static void xen_disk_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
blockdev_class->realize = xen_disk_realize;
blockdev_class->unrealize = xen_disk_unrealize;
dev_class->desc = "Xen Disk Device";
}
static const TypeInfo xen_disk_type_info = {
.name = TYPE_XEN_DISK_DEVICE,
.parent = TYPE_XEN_BLOCK_DEVICE,
.instance_size = sizeof(XenDiskDevice),
.class_init = xen_disk_class_init,
};
static void xen_cdrom_unrealize(XenBlockDevice *blockdev)
{
trace_xen_cdrom_unrealize();
}
static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
{
BlockConf *conf = &blockdev->props.conf;
trace_xen_cdrom_realize();
blockdev->device_type = "cdrom";
if (!conf->blk) {
int rc;
/* Set up an empty drive */
conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
if (!rc) {
error_setg_errno(errp, -rc, "failed to create drive");
return;
}
}
blockdev->info = VDISK_READONLY | VDISK_CDROM;
}
static void xen_cdrom_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
blockdev_class->realize = xen_cdrom_realize;
blockdev_class->unrealize = xen_cdrom_unrealize;
dev_class->desc = "Xen CD-ROM Device";
}
static const TypeInfo xen_cdrom_type_info = {
.name = TYPE_XEN_CDROM_DEVICE,
.parent = TYPE_XEN_BLOCK_DEVICE,
.instance_size = sizeof(XenCDRomDevice),
.class_init = xen_cdrom_class_init,
};
static void xen_block_register_types(void)
{
type_register_static(&xen_block_type_info);
type_register_static(&xen_disk_type_info);
type_register_static(&xen_cdrom_type_info);
}
type_init(xen_block_register_types)
static void xen_block_blockdev_del(const char *node_name, Error **errp)
{
trace_xen_block_blockdev_del(node_name);
qmp_blockdev_del(node_name, errp);
}
static char *xen_block_blockdev_add(const char *id, QDict *qdict,
Error **errp)
{
ERRP_GUARD();
const char *driver = qdict_get_try_str(qdict, "driver");
BlockdevOptions *options = NULL;
char *node_name;
Visitor *v;
if (!driver) {
error_setg(errp, "no 'driver' parameter");
return NULL;
}
node_name = g_strdup_printf("%s-%s", id, driver);
qdict_put_str(qdict, "node-name", node_name);
trace_xen_block_blockdev_add(node_name);
v = qobject_input_visitor_new(QOBJECT(qdict));
visit_type_BlockdevOptions(v, NULL, &options, errp);
visit_free(v);
if (!options) {
goto fail;
}
qmp_blockdev_add(options, errp);
if (*errp) {
goto fail;
}
qapi_free_BlockdevOptions(options);
return node_name;
fail:
if (options) {
qapi_free_BlockdevOptions(options);
}
g_free(node_name);
return NULL;
}
static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
{
ERRP_GUARD();
char *node_name = drive->node_name;
if (node_name) {
xen_block_blockdev_del(node_name, errp);
if (*errp) {
return;
}
g_free(node_name);
drive->node_name = NULL;
}
g_free(drive->id);
g_free(drive);
}
static XenBlockDrive *xen_block_drive_create(const char *id,
const char *device_type,
QDict *opts, Error **errp)
{
ERRP_GUARD();
const char *params = qdict_get_try_str(opts, "params");
const char *mode = qdict_get_try_str(opts, "mode");
const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
char *driver = NULL;
char *filename = NULL;
XenBlockDrive *drive = NULL;
QDict *file_layer;
QDict *driver_layer;
struct stat st;
int rc;
if (params) {
char **v = g_strsplit(params, ":", 2);
if (v[1] == NULL) {
filename = g_strdup(v[0]);
driver = g_strdup("raw");
} else {
if (strcmp(v[0], "aio") == 0) {
driver = g_strdup("raw");
} else if (strcmp(v[0], "vhd") == 0) {
driver = g_strdup("vpc");
} else {
driver = g_strdup(v[0]);
}
filename = g_strdup(v[1]);
}
g_strfreev(v);
} else {
error_setg(errp, "no params");
goto done;
}
assert(filename);
assert(driver);
drive = g_new0(XenBlockDrive, 1);
drive->id = g_strdup(id);
rc = stat(filename, &st);
if (rc) {
error_setg_errno(errp, errno, "Could not stat file '%s'", filename);
goto done;
}
file_layer = qdict_new();
driver_layer = qdict_new();
if (S_ISBLK(st.st_mode)) {
qdict_put_str(file_layer, "driver", "host_device");
} else {
qdict_put_str(file_layer, "driver", "file");
}
qdict_put_str(file_layer, "filename", filename);
if (mode && *mode != 'w') {
qdict_put_bool(file_layer, "read-only", true);
}
if (direct_io_safe) {
unsigned long value;
if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
QDict *cache_qdict = qdict_new();
qdict_put_bool(cache_qdict, "direct", true);
qdict_put(file_layer, "cache", cache_qdict);
qdict_put_str(file_layer, "aio", "native");
}
}
if (discard_enable) {
unsigned long value;
if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
qdict_put_str(file_layer, "discard", "unmap");
qdict_put_str(driver_layer, "discard", "unmap");
}
}
/*
* It is necessary to turn file locking off as an emulated device
* may have already opened the same image file.
*/
qdict_put_str(file_layer, "locking", "off");
qdict_put_str(driver_layer, "driver", driver);
qdict_put(driver_layer, "file", file_layer);
g_assert(!drive->node_name);
drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
errp);
qobject_unref(driver_layer);
done:
g_free(filename);
g_free(driver);
if (*errp) {
xen_block_drive_destroy(drive, NULL);
return NULL;
}
return drive;
}
static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
{
return drive->node_name ? drive->node_name : "";
}
static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
Error **errp)
{
qmp_object_del(iothread->id, errp);
g_free(iothread->id);
g_free(iothread);
}
static XenBlockIOThread *xen_block_iothread_create(const char *id,
Error **errp)
{
ERRP_GUARD();
XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
ObjectOptions *opts;
iothread->id = g_strdup(id);
opts = g_new(ObjectOptions, 1);
*opts = (ObjectOptions) {
.qom_type = OBJECT_TYPE_IOTHREAD,
.id = g_strdup(id),
};
qmp_object_add(opts, errp);
qapi_free_ObjectOptions(opts);
if (*errp) {
g_free(iothread->id);
g_free(iothread);
return NULL;
}
return iothread;
}
static void xen_block_device_create(XenBackendInstance *backend,
QDict *opts, Error **errp)
{
ERRP_GUARD();
XenBus *xenbus = xen_backend_get_bus(backend);
const char *name = xen_backend_get_name(backend);
unsigned long number;
const char *vdev, *device_type;
XenBlockDrive *drive = NULL;
XenBlockIOThread *iothread = NULL;
XenDevice *xendev = NULL;
const char *type;
XenBlockDevice *blockdev;
if (qemu_strtoul(name, NULL, 10, &number)) {
error_setg(errp, "failed to parse name '%s'", name);
goto fail;
}
trace_xen_block_device_create(number);
vdev = qdict_get_try_str(opts, "dev");
if (!vdev) {
error_setg(errp, "no dev parameter");
goto fail;
}
device_type = qdict_get_try_str(opts, "device-type");
if (!device_type) {
error_setg(errp, "no device-type parameter");
goto fail;
}
if (!strcmp(device_type, "disk")) {
type = TYPE_XEN_DISK_DEVICE;
} else if (!strcmp(device_type, "cdrom")) {
type = TYPE_XEN_CDROM_DEVICE;
} else {
error_setg(errp, "invalid device-type parameter '%s'", device_type);
goto fail;
}
drive = xen_block_drive_create(vdev, device_type, opts, errp);
if (!drive) {
error_prepend(errp, "failed to create drive: ");
goto fail;
}
iothread = xen_block_iothread_create(vdev, errp);
if (*errp) {
error_prepend(errp, "failed to create iothread: ");
goto fail;
}
xendev = XEN_DEVICE(qdev_new(type));
blockdev = XEN_BLOCK_DEVICE(xendev);
if (!object_property_set_str(OBJECT(xendev), "vdev", vdev,
errp)) {
error_prepend(errp, "failed to set 'vdev': ");
goto fail;
}
if (!object_property_set_str(OBJECT(xendev), "drive",
xen_block_drive_get_node_name(drive),
errp)) {
error_prepend(errp, "failed to set 'drive': ");
goto fail;
}
if (!object_property_set_str(OBJECT(xendev), "iothread", iothread->id,
errp)) {
error_prepend(errp, "failed to set 'iothread': ");
goto fail;
}
blockdev->iothread = iothread;
blockdev->drive = drive;
if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) {
error_prepend(errp, "realization of device %s failed: ", type);
goto fail;
}
xen_backend_set_device(backend, xendev);
return;
fail:
if (xendev) {
object_unparent(OBJECT(xendev));
}
if (iothread) {
xen_block_iothread_destroy(iothread, NULL);
}
if (drive) {
xen_block_drive_destroy(drive, NULL);
}
}
static void xen_block_device_destroy(XenBackendInstance *backend,
Error **errp)
{
ERRP_GUARD();
XenDevice *xendev = xen_backend_get_device(backend);
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
XenBlockDrive *drive = blockdev->drive;
XenBlockIOThread *iothread = blockdev->iothread;
trace_xen_block_device_destroy(vdev->number);
object_unparent(OBJECT(xendev));
/*
* Drain all pending RCU callbacks as object_unparent() frees `xendev'
* in a RCU callback.
* And due to the property "drive" still existing in `xendev', we
* can't destroy the XenBlockDrive associated with `xendev' with
* xen_block_drive_destroy() below.
*/
drain_call_rcu();
if (iothread) {
xen_block_iothread_destroy(iothread, errp);
if (*errp) {
error_prepend(errp, "failed to destroy iothread: ");
return;
}
}
if (drive) {
xen_block_drive_destroy(drive, errp);
if (*errp) {
error_prepend(errp, "failed to destroy drive: ");
return;
}
}
}
static const XenBackendInfo xen_block_backend_info = {
.type = "qdisk",
.create = xen_block_device_create,
.destroy = xen_block_device_destroy,
};
static void xen_block_register_backend(void)
{
xen_backend_register(&xen_block_backend_info);
}
xen_backend_init(xen_block_register_backend);
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