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qemu/hw/block/xen-block.c
David Woodhouse 072519037d hw/xen: Only advertise ring-page-order for xen-block if gnttab supports it 
Whem emulating Xen, multi-page grants are distinctly non-trivial and we
have elected not to support them for the time being. Don't advertise
them to the guest.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-07 17:04:30 +00:00

1028 lines
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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 "trace.h"
static char *xen_block_get_name(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
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) {
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);
}
static const BlockDevOps xen_block_dev_ops = {
.resize_cb = xen_block_resize_cb,
};
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;
}
blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
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);
}
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 *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",
name, vdev->partition);
g_free(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 = (202 << 8) | (vdev->disk << 4) |
vdev->partition;
} else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
vdev->number = (1 << 28) | (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 = (3 << 8) | (vdev->disk << 6) | vdev->partition;
} else if ((vdev->disk == 2 || vdev->disk == 3) &&
vdev->partition < (1 << 6)) {
vdev->number = (22 << 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 = (8 << 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);
file_layer = qdict_new();
driver_layer = qdict_new();
rc = stat(filename, &st);
if (rc) {
error_setg_errno(errp, errno, "Could not stat file '%s'", filename);
goto done;
}
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);
g_free(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);
g_free(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:
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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