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cb32314607
qemu/hw/xen/xen-bus.c
Anthony PERARD cb32314607 xen-bus: Fix backend state transition on device reset 
When a frontend wants to reset its state and the backend one, it
starts with setting "Closing", then waits for the backend (QEMU) to do
the same.

But when QEMU is setting "Closing" to its state, it triggers an event
(xenstore watch) that re-execute xen_device_backend_changed() and set
the backend state to "Closed". QEMU should wait for the frontend to
set "Closed" before doing the same.

Before setting "Closed" to the backend_state, we are also going to
check if there is a frontend. If that the case, when the backend state
is set to "Closing" the frontend should react and sets its state to
"Closing" then "Closed". The backend should wait for that to happen.

Fixes: b6af8926fb
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Message-Id: <20190823101534.465-2-anthony.perard@citrix.com>
2019-08-27 14:18:28 +01:00

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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/main-loop.h"
#include "qemu/module.h"
#include "qemu/uuid.h"
#include "hw/qdev-properties.h"
#include "hw/sysbus.h"
#include "hw/xen/xen.h"
#include "hw/xen/xen-backend.h"
#include "hw/xen/xen-bus.h"
#include "hw/xen/xen-bus-helper.h"
#include "monitor/monitor.h"
#include "qapi/error.h"
#include "qapi/qmp/qdict.h"
#include "sysemu/sysemu.h"
#include "trace.h"
static char *xen_device_get_backend_path(XenDevice *xendev)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(xendev));
const char *backend = xendev_class->backend;
if (!backend) {
backend = type;
}
return g_strdup_printf("/local/domain/%u/backend/%s/%u/%s",
xenbus->backend_id, backend, xendev->frontend_id,
xendev->name);
}
static char *xen_device_get_frontend_path(XenDevice *xendev)
{
XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(xendev));
const char *device = xendev_class->device;
if (!device) {
device = type;
}
return g_strdup_printf("/local/domain/%u/device/%s/%s",
xendev->frontend_id, device, xendev->name);
}
static void xen_device_unplug(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
const char *type = object_get_typename(OBJECT(xendev));
Error *local_err = NULL;
xs_transaction_t tid;
trace_xen_device_unplug(type, xendev->name);
/* Mimic the way the Xen toolstack does an unplug */
again:
tid = xs_transaction_start(xenbus->xsh);
if (tid == XBT_NULL) {
error_setg_errno(errp, errno, "failed xs_transaction_start");
return;
}
xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "online",
&local_err, "%u", 0);
if (local_err) {
goto abort;
}
xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "state",
&local_err, "%u", XenbusStateClosing);
if (local_err) {
goto abort;
}
if (!xs_transaction_end(xenbus->xsh, tid, false)) {
if (errno == EAGAIN) {
goto again;
}
error_setg_errno(errp, errno, "failed xs_transaction_end");
}
return;
abort:
/*
* We only abort if there is already a failure so ignore any error
* from ending the transaction.
*/
xs_transaction_end(xenbus->xsh, tid, true);
error_propagate(errp, local_err);
}
static void xen_bus_print_dev(Monitor *mon, DeviceState *dev, int indent)
{
XenDevice *xendev = XEN_DEVICE(dev);
monitor_printf(mon, "%*sname = '%s' frontend_id = %u\n",
indent, "", xendev->name, xendev->frontend_id);
}
static char *xen_bus_get_dev_path(DeviceState *dev)
{
return xen_device_get_backend_path(XEN_DEVICE(dev));
}
struct XenWatch {
char *node, *key;
char *token;
XenWatchHandler handler;
void *opaque;
Notifier notifier;
};
static void watch_notify(Notifier *n, void *data)
{
XenWatch *watch = container_of(n, XenWatch, notifier);
const char *token = data;
if (!strcmp(watch->token, token)) {
watch->handler(watch->opaque);
}
}
static XenWatch *new_watch(const char *node, const char *key,
XenWatchHandler handler, void *opaque)
{
XenWatch *watch = g_new0(XenWatch, 1);
QemuUUID uuid;
qemu_uuid_generate(&uuid);
watch->token = qemu_uuid_unparse_strdup(&uuid);
watch->node = g_strdup(node);
watch->key = g_strdup(key);
watch->handler = handler;
watch->opaque = opaque;
watch->notifier.notify = watch_notify;
return watch;
}
static void free_watch(XenWatch *watch)
{
g_free(watch->token);
g_free(watch->key);
g_free(watch->node);
g_free(watch);
}
static XenWatch *xen_bus_add_watch(XenBus *xenbus, const char *node,
const char *key, XenWatchHandler handler,
void *opaque, Error **errp)
{
XenWatch *watch = new_watch(node, key, handler, opaque);
Error *local_err = NULL;
trace_xen_bus_add_watch(watch->node, watch->key, watch->token);
notifier_list_add(&xenbus->watch_notifiers, &watch->notifier);
xs_node_watch(xenbus->xsh, node, key, watch->token, &local_err);
if (local_err) {
error_propagate(errp, local_err);
notifier_remove(&watch->notifier);
free_watch(watch);
return NULL;
}
return watch;
}
static void xen_bus_remove_watch(XenBus *xenbus, XenWatch *watch,
Error **errp)
{
trace_xen_bus_remove_watch(watch->node, watch->key, watch->token);
xs_node_unwatch(xenbus->xsh, watch->node, watch->key, watch->token,
errp);
notifier_remove(&watch->notifier);
free_watch(watch);
}
static void xen_bus_backend_create(XenBus *xenbus, const char *type,
const char *name, char *path,
Error **errp)
{
xs_transaction_t tid;
char **key;
QDict *opts;
unsigned int i, n;
Error *local_err = NULL;
trace_xen_bus_backend_create(type, path);
again:
tid = xs_transaction_start(xenbus->xsh);
if (tid == XBT_NULL) {
error_setg(errp, "failed xs_transaction_start");
return;
}
key = xs_directory(xenbus->xsh, tid, path, &n);
if (!key) {
if (!xs_transaction_end(xenbus->xsh, tid, true)) {
error_setg_errno(errp, errno, "failed xs_transaction_end");
}
return;
}
opts = qdict_new();
for (i = 0; i < n; i++) {
char *val;
/*
* Assume anything found in the xenstore backend area, other than
* the keys created for a generic XenDevice, are parameters
* to be used to configure the backend.
*/
if (!strcmp(key[i], "state") ||
!strcmp(key[i], "online") ||
!strcmp(key[i], "frontend") ||
!strcmp(key[i], "frontend-id") ||
!strcmp(key[i], "hotplug-status"))
continue;
if (xs_node_scanf(xenbus->xsh, tid, path, key[i], NULL, "%ms",
&val) == 1) {
qdict_put_str(opts, key[i], val);
free(val);
}
}
free(key);
if (!xs_transaction_end(xenbus->xsh, tid, false)) {
qobject_unref(opts);
if (errno == EAGAIN) {
goto again;
}
error_setg_errno(errp, errno, "failed xs_transaction_end");
return;
}
xen_backend_device_create(xenbus, type, name, opts, &local_err);
qobject_unref(opts);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to create '%s' device '%s': ",
type, name);
}
}
static void xen_bus_type_enumerate(XenBus *xenbus, const char *type)
{
char *domain_path = g_strdup_printf("backend/%s/%u", type, xen_domid);
char **backend;
unsigned int i, n;
trace_xen_bus_type_enumerate(type);
backend = xs_directory(xenbus->xsh, XBT_NULL, domain_path, &n);
if (!backend) {
goto out;
}
for (i = 0; i < n; i++) {
char *backend_path = g_strdup_printf("%s/%s", domain_path,
backend[i]);
enum xenbus_state backend_state;
if (xs_node_scanf(xenbus->xsh, XBT_NULL, backend_path, "state",
NULL, "%u", &backend_state) != 1)
backend_state = XenbusStateUnknown;
if (backend_state == XenbusStateInitialising) {
Error *local_err = NULL;
xen_bus_backend_create(xenbus, type, backend[i], backend_path,
&local_err);
if (local_err) {
error_report_err(local_err);
}
}
g_free(backend_path);
}
free(backend);
out:
g_free(domain_path);
}
static void xen_bus_enumerate(void *opaque)
{
XenBus *xenbus = opaque;
char **type;
unsigned int i, n;
trace_xen_bus_enumerate();
type = xs_directory(xenbus->xsh, XBT_NULL, "backend", &n);
if (!type) {
return;
}
for (i = 0; i < n; i++) {
xen_bus_type_enumerate(xenbus, type[i]);
}
free(type);
}
static void xen_bus_unrealize(BusState *bus, Error **errp)
{
XenBus *xenbus = XEN_BUS(bus);
trace_xen_bus_unrealize();
if (xenbus->backend_watch) {
xen_bus_remove_watch(xenbus, xenbus->backend_watch, NULL);
xenbus->backend_watch = NULL;
}
if (!xenbus->xsh) {
return;
}
qemu_set_fd_handler(xs_fileno(xenbus->xsh), NULL, NULL, NULL);
xs_close(xenbus->xsh);
}
static void xen_bus_watch(void *opaque)
{
XenBus *xenbus = opaque;
char **v;
const char *token;
g_assert(xenbus->xsh);
v = xs_check_watch(xenbus->xsh);
if (!v) {
return;
}
token = v[XS_WATCH_TOKEN];
trace_xen_bus_watch(token);
notifier_list_notify(&xenbus->watch_notifiers, (void *)token);
free(v);
}
static void xen_bus_realize(BusState *bus, Error **errp)
{
XenBus *xenbus = XEN_BUS(bus);
unsigned int domid;
Error *local_err = NULL;
trace_xen_bus_realize();
xenbus->xsh = xs_open(0);
if (!xenbus->xsh) {
error_setg_errno(errp, errno, "failed xs_open");
goto fail;
}
if (xs_node_scanf(xenbus->xsh, XBT_NULL, "", /* domain root node */
"domid", NULL, "%u", &domid) == 1) {
xenbus->backend_id = domid;
} else {
xenbus->backend_id = 0; /* Assume lack of node means dom0 */
}
notifier_list_init(&xenbus->watch_notifiers);
qemu_set_fd_handler(xs_fileno(xenbus->xsh), xen_bus_watch, NULL,
xenbus);
module_call_init(MODULE_INIT_XEN_BACKEND);
xenbus->backend_watch =
xen_bus_add_watch(xenbus, "", /* domain root node */
"backend", xen_bus_enumerate, xenbus, &local_err);
if (local_err) {
/* This need not be treated as a hard error so don't propagate */
error_reportf_err(local_err,
"failed to set up enumeration watch: ");
}
return;
fail:
xen_bus_unrealize(bus, &error_abort);
}
static void xen_bus_unplug_request(HotplugHandler *hotplug,
DeviceState *dev,
Error **errp)
{
XenDevice *xendev = XEN_DEVICE(dev);
xen_device_unplug(xendev, errp);
}
static void xen_bus_class_init(ObjectClass *class, void *data)
{
BusClass *bus_class = BUS_CLASS(class);
HotplugHandlerClass *hotplug_class = HOTPLUG_HANDLER_CLASS(class);
bus_class->print_dev = xen_bus_print_dev;
bus_class->get_dev_path = xen_bus_get_dev_path;
bus_class->realize = xen_bus_realize;
bus_class->unrealize = xen_bus_unrealize;
hotplug_class->unplug_request = xen_bus_unplug_request;
}
static const TypeInfo xen_bus_type_info = {
.name = TYPE_XEN_BUS,
.parent = TYPE_BUS,
.instance_size = sizeof(XenBus),
.class_size = sizeof(XenBusClass),
.class_init = xen_bus_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_HOTPLUG_HANDLER },
{ }
},
};
void xen_device_backend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
va_list ap;
g_assert(xenbus->xsh);
va_start(ap, fmt);
xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
&local_err, fmt, ap);
va_end(ap);
if (local_err) {
error_report_err(local_err);
}
}
static int xen_device_backend_scanf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
va_list ap;
int rc;
g_assert(xenbus->xsh);
va_start(ap, fmt);
rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
NULL, fmt, ap);
va_end(ap);
return rc;
}
void xen_device_backend_set_state(XenDevice *xendev,
enum xenbus_state state)
{
const char *type = object_get_typename(OBJECT(xendev));
if (xendev->backend_state == state) {
return;
}
trace_xen_device_backend_state(type, xendev->name,
xs_strstate(state));
xendev->backend_state = state;
xen_device_backend_printf(xendev, "state", "%u", state);
}
enum xenbus_state xen_device_backend_get_state(XenDevice *xendev)
{
return xendev->backend_state;
}
static void xen_device_backend_set_online(XenDevice *xendev, bool online)
{
const char *type = object_get_typename(OBJECT(xendev));
if (xendev->backend_online == online) {
return;
}
trace_xen_device_backend_online(type, xendev->name, online);
xendev->backend_online = online;
xen_device_backend_printf(xendev, "online", "%u", online);
}
/*
* Tell from the state whether the frontend is likely alive,
* i.e. it will react to a change of state of the backend.
*/
static bool xen_device_state_is_active(enum xenbus_state state)
{
switch (state) {
case XenbusStateInitWait:
case XenbusStateInitialised:
case XenbusStateConnected:
case XenbusStateClosing:
return true;
default:
return false;
}
}
static void xen_device_backend_changed(void *opaque)
{
XenDevice *xendev = opaque;
const char *type = object_get_typename(OBJECT(xendev));
enum xenbus_state state;
unsigned int online;
trace_xen_device_backend_changed(type, xendev->name);
if (xen_device_backend_scanf(xendev, "state", "%u", &state) != 1) {
state = XenbusStateUnknown;
}
xen_device_backend_set_state(xendev, state);
if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) {
online = 0;
}
xen_device_backend_set_online(xendev, !!online);
/*
* If the toolstack (or unplug request callback) has set the backend
* state to Closing, but there is no active frontend then set the
* backend state to Closed.
*/
if (xendev->backend_state == XenbusStateClosing &&
!xen_device_state_is_active(state)) {
xen_device_backend_set_state(xendev, XenbusStateClosed);
}
/*
* If a backend is still 'online' then we should leave it alone but,
* if a backend is not 'online', then the device should be destroyed
* once the state is Closed.
*/
if (!xendev->backend_online &&
(xendev->backend_state == XenbusStateClosed ||
xendev->backend_state == XenbusStateInitialising ||
xendev->backend_state == XenbusStateInitWait ||
xendev->backend_state == XenbusStateUnknown)) {
Error *local_err = NULL;
if (!xen_backend_try_device_destroy(xendev, &local_err)) {
object_unparent(OBJECT(xendev));
}
if (local_err) {
error_report_err(local_err);
}
}
}
static void xen_device_backend_create(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
struct xs_permissions perms[2];
Error *local_err = NULL;
xendev->backend_path = xen_device_get_backend_path(xendev);
perms[0].id = xenbus->backend_id;
perms[0].perms = XS_PERM_NONE;
perms[1].id = xendev->frontend_id;
perms[1].perms = XS_PERM_READ;
g_assert(xenbus->xsh);
xs_node_create(xenbus->xsh, XBT_NULL, xendev->backend_path, perms,
ARRAY_SIZE(perms), &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to create backend: ");
return;
}
xendev->backend_state_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"state", xen_device_backend_changed,
xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend state: ");
return;
}
xendev->backend_online_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"online", xen_device_backend_changed,
xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend online: ");
return;
}
}
static void xen_device_backend_destroy(XenDevice *xendev)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
if (xendev->backend_online_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_online_watch, NULL);
xendev->backend_online_watch = NULL;
}
if (xendev->backend_state_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_state_watch, NULL);
xendev->backend_state_watch = NULL;
}
if (!xendev->backend_path) {
return;
}
g_assert(xenbus->xsh);
xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->backend_path,
&local_err);
g_free(xendev->backend_path);
xendev->backend_path = NULL;
if (local_err) {
error_report_err(local_err);
}
}
void xen_device_frontend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
va_list ap;
g_assert(xenbus->xsh);
va_start(ap, fmt);
xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
&local_err, fmt, ap);
va_end(ap);
if (local_err) {
error_report_err(local_err);
}
}
int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
va_list ap;
int rc;
g_assert(xenbus->xsh);
va_start(ap, fmt);
rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
NULL, fmt, ap);
va_end(ap);
return rc;
}
static void xen_device_frontend_set_state(XenDevice *xendev,
enum xenbus_state state)
{
const char *type = object_get_typename(OBJECT(xendev));
if (xendev->frontend_state == state) {
return;
}
trace_xen_device_frontend_state(type, xendev->name,
xs_strstate(state));
xendev->frontend_state = state;
xen_device_frontend_printf(xendev, "state", "%u", state);
}
static void xen_device_frontend_changed(void *opaque)
{
XenDevice *xendev = opaque;
XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(xendev));
enum xenbus_state state;
trace_xen_device_frontend_changed(type, xendev->name);
if (xen_device_frontend_scanf(xendev, "state", "%u", &state) != 1) {
state = XenbusStateUnknown;
}
xen_device_frontend_set_state(xendev, state);
if (state == XenbusStateInitialising &&
xendev->backend_state == XenbusStateClosed &&
xendev->backend_online) {
/*
* The frontend is re-initializing so switch back to
* InitWait.
*/
xen_device_backend_set_state(xendev, XenbusStateInitWait);
return;
}
if (xendev_class->frontend_changed) {
Error *local_err = NULL;
xendev_class->frontend_changed(xendev, state, &local_err);
if (local_err) {
error_reportf_err(local_err, "frontend change error: ");
}
}
}
static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
struct xs_permissions perms[2];
Error *local_err = NULL;
xendev->frontend_path = xen_device_get_frontend_path(xendev);
perms[0].id = xendev->frontend_id;
perms[0].perms = XS_PERM_NONE;
perms[1].id = xenbus->backend_id;
perms[1].perms = XS_PERM_READ | XS_PERM_WRITE;
g_assert(xenbus->xsh);
xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms,
ARRAY_SIZE(perms), &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to create frontend: ");
return;
}
xendev->frontend_state_watch =
xen_bus_add_watch(xenbus, xendev->frontend_path, "state",
xen_device_frontend_changed, xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch frontend state: ");
}
}
static void xen_device_frontend_destroy(XenDevice *xendev)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
if (xendev->frontend_state_watch) {
xen_bus_remove_watch(xenbus, xendev->frontend_state_watch, NULL);
xendev->frontend_state_watch = NULL;
}
if (!xendev->frontend_path) {
return;
}
g_assert(xenbus->xsh);
xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->frontend_path,
&local_err);
g_free(xendev->frontend_path);
xendev->frontend_path = NULL;
if (local_err) {
error_report_err(local_err);
}
}
void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
Error **errp)
{
if (xengnttab_set_max_grants(xendev->xgth, nr_refs)) {
error_setg_errno(errp, errno, "xengnttab_set_max_grants failed");
}
}
void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
unsigned int nr_refs, int prot,
Error **errp)
{
void *map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_refs,
xendev->frontend_id, refs,
prot);
if (!map) {
error_setg_errno(errp, errno,
"xengnttab_map_domain_grant_refs failed");
}
return map;
}
void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
unsigned int nr_refs, Error **errp)
{
if (xengnttab_unmap(xendev->xgth, map, nr_refs)) {
error_setg_errno(errp, errno, "xengnttab_unmap failed");
}
}
static void compat_copy_grant_refs(XenDevice *xendev, bool to_domain,
XenDeviceGrantCopySegment segs[],
unsigned int nr_segs, Error **errp)
{
uint32_t *refs = g_new(uint32_t, nr_segs);
int prot = to_domain ? PROT_WRITE : PROT_READ;
void *map;
unsigned int i;
for (i = 0; i < nr_segs; i++) {
XenDeviceGrantCopySegment *seg = &segs[i];
refs[i] = to_domain ? seg->dest.foreign.ref :
seg->source.foreign.ref;
}
map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_segs,
xendev->frontend_id, refs,
prot);
if (!map) {
error_setg_errno(errp, errno,
"xengnttab_map_domain_grant_refs failed");
goto done;
}
for (i = 0; i < nr_segs; i++) {
XenDeviceGrantCopySegment *seg = &segs[i];
void *page = map + (i * XC_PAGE_SIZE);
if (to_domain) {
memcpy(page + seg->dest.foreign.offset, seg->source.virt,
seg->len);
} else {
memcpy(seg->dest.virt, page + seg->source.foreign.offset,
seg->len);
}
}
if (xengnttab_unmap(xendev->xgth, map, nr_segs)) {
error_setg_errno(errp, errno, "xengnttab_unmap failed");
}
done:
g_free(refs);
}
void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
XenDeviceGrantCopySegment segs[],
unsigned int nr_segs, Error **errp)
{
xengnttab_grant_copy_segment_t *xengnttab_segs;
unsigned int i;
if (!xendev->feature_grant_copy) {
compat_copy_grant_refs(xendev, to_domain, segs, nr_segs, errp);
return;
}
xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs);
for (i = 0; i < nr_segs; i++) {
XenDeviceGrantCopySegment *seg = &segs[i];
xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
if (to_domain) {
xengnttab_seg->flags = GNTCOPY_dest_gref;
xengnttab_seg->dest.foreign.domid = xendev->frontend_id;
xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref;
xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset;
xengnttab_seg->source.virt = seg->source.virt;
} else {
xengnttab_seg->flags = GNTCOPY_source_gref;
xengnttab_seg->source.foreign.domid = xendev->frontend_id;
xengnttab_seg->source.foreign.ref = seg->source.foreign.ref;
xengnttab_seg->source.foreign.offset =
seg->source.foreign.offset;
xengnttab_seg->dest.virt = seg->dest.virt;
}
xengnttab_seg->len = seg->len;
}
if (xengnttab_grant_copy(xendev->xgth, nr_segs, xengnttab_segs)) {
error_setg_errno(errp, errno, "xengnttab_grant_copy failed");
goto done;
}
for (i = 0; i < nr_segs; i++) {
xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
if (xengnttab_seg->status != GNTST_okay) {
error_setg(errp, "xengnttab_grant_copy seg[%u] failed", i);
break;
}
}
done:
g_free(xengnttab_segs);
}
struct XenEventChannel {
QLIST_ENTRY(XenEventChannel) list;
AioContext *ctx;
xenevtchn_handle *xeh;
evtchn_port_t local_port;
XenEventHandler handler;
void *opaque;
};
static bool xen_device_poll(void *opaque)
{
XenEventChannel *channel = opaque;
return channel->handler(channel->opaque);
}
static void xen_device_event(void *opaque)
{
XenEventChannel *channel = opaque;
unsigned long port = xenevtchn_pending(channel->xeh);
if (port == channel->local_port) {
xen_device_poll(channel);
xenevtchn_unmask(channel->xeh, port);
}
}
XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
AioContext *ctx,
unsigned int port,
XenEventHandler handler,
void *opaque, Error **errp)
{
XenEventChannel *channel = g_new0(XenEventChannel, 1);
xenevtchn_port_or_error_t local_port;
channel->xeh = xenevtchn_open(NULL, 0);
if (!channel->xeh) {
error_setg_errno(errp, errno, "failed xenevtchn_open");
goto fail;
}
local_port = xenevtchn_bind_interdomain(channel->xeh,
xendev->frontend_id,
port);
if (local_port < 0) {
error_setg_errno(errp, errno, "xenevtchn_bind_interdomain failed");
goto fail;
}
channel->local_port = local_port;
channel->handler = handler;
channel->opaque = opaque;
channel->ctx = ctx;
aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
xen_device_event, NULL, xen_device_poll, channel);
QLIST_INSERT_HEAD(&xendev->event_channels, channel, list);
return channel;
fail:
if (channel->xeh) {
xenevtchn_close(channel->xeh);
}
g_free(channel);
return NULL;
}
void xen_device_notify_event_channel(XenDevice *xendev,
XenEventChannel *channel,
Error **errp)
{
if (!channel) {
error_setg(errp, "bad channel");
return;
}
if (xenevtchn_notify(channel->xeh, channel->local_port) < 0) {
error_setg_errno(errp, errno, "xenevtchn_notify failed");
}
}
void xen_device_unbind_event_channel(XenDevice *xendev,
XenEventChannel *channel,
Error **errp)
{
if (!channel) {
error_setg(errp, "bad channel");
return;
}
QLIST_REMOVE(channel, list);
aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
NULL, NULL, NULL, NULL);
if (xenevtchn_unbind(channel->xeh, channel->local_port) < 0) {
error_setg_errno(errp, errno, "xenevtchn_unbind failed");
}
xenevtchn_close(channel->xeh);
g_free(channel);
}
static void xen_device_unrealize(DeviceState *dev, Error **errp)
{
XenDevice *xendev = XEN_DEVICE(dev);
XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(xendev));
XenEventChannel *channel, *next;
if (!xendev->name) {
return;
}
trace_xen_device_unrealize(type, xendev->name);
if (xendev->exit.notify) {
qemu_remove_exit_notifier(&xendev->exit);
xendev->exit.notify = NULL;
}
if (xendev_class->unrealize) {
xendev_class->unrealize(xendev, errp);
}
/* Make sure all event channels are cleaned up */
QLIST_FOREACH_SAFE(channel, &xendev->event_channels, list, next) {
xen_device_unbind_event_channel(xendev, channel, NULL);
}
xen_device_frontend_destroy(xendev);
xen_device_backend_destroy(xendev);
if (xendev->xgth) {
xengnttab_close(xendev->xgth);
xendev->xgth = NULL;
}
g_free(xendev->name);
xendev->name = NULL;
}
static void xen_device_exit(Notifier *n, void *data)
{
XenDevice *xendev = container_of(n, XenDevice, exit);
xen_device_unrealize(DEVICE(xendev), &error_abort);
}
static void xen_device_realize(DeviceState *dev, Error **errp)
{
XenDevice *xendev = XEN_DEVICE(dev);
XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
const char *type = object_get_typename(OBJECT(xendev));
Error *local_err = NULL;
if (xendev->frontend_id == DOMID_INVALID) {
xendev->frontend_id = xen_domid;
}
if (xendev->frontend_id >= DOMID_FIRST_RESERVED) {
error_setg(errp, "invalid frontend-id");
goto unrealize;
}
if (!xendev_class->get_name) {
error_setg(errp, "get_name method not implemented");
goto unrealize;
}
xendev->name = xendev_class->get_name(xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to get device name: ");
goto unrealize;
}
trace_xen_device_realize(type, xendev->name);
xendev->xgth = xengnttab_open(NULL, 0);
if (!xendev->xgth) {
error_setg_errno(errp, errno, "failed xengnttab_open");
goto unrealize;
}
xendev->feature_grant_copy =
(xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
xen_device_backend_create(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto unrealize;
}
xen_device_frontend_create(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto unrealize;
}
if (xendev_class->realize) {
xendev_class->realize(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto unrealize;
}
}
xen_device_backend_printf(xendev, "frontend", "%s",
xendev->frontend_path);
xen_device_backend_printf(xendev, "frontend-id", "%u",
xendev->frontend_id);
xen_device_backend_printf(xendev, "hotplug-status", "connected");
xen_device_backend_set_online(xendev, true);
xen_device_backend_set_state(xendev, XenbusStateInitWait);
xen_device_frontend_printf(xendev, "backend", "%s",
xendev->backend_path);
xen_device_frontend_printf(xendev, "backend-id", "%u",
xenbus->backend_id);
xen_device_frontend_set_state(xendev, XenbusStateInitialising);
xendev->exit.notify = xen_device_exit;
qemu_add_exit_notifier(&xendev->exit);
return;
unrealize:
xen_device_unrealize(dev, &error_abort);
}
static Property xen_device_props[] = {
DEFINE_PROP_UINT16("frontend-id", XenDevice, frontend_id,
DOMID_INVALID),
DEFINE_PROP_END_OF_LIST()
};
static void xen_device_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
dev_class->realize = xen_device_realize;
dev_class->unrealize = xen_device_unrealize;
dev_class->props = xen_device_props;
dev_class->bus_type = TYPE_XEN_BUS;
}
static const TypeInfo xen_device_type_info = {
.name = TYPE_XEN_DEVICE,
.parent = TYPE_DEVICE,
.instance_size = sizeof(XenDevice),
.abstract = true,
.class_size = sizeof(XenDeviceClass),
.class_init = xen_device_class_init,
};
typedef struct XenBridge {
SysBusDevice busdev;
} XenBridge;
#define TYPE_XEN_BRIDGE "xen-bridge"
static const TypeInfo xen_bridge_type_info = {
.name = TYPE_XEN_BRIDGE,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(XenBridge),
};
static void xen_register_types(void)
{
type_register_static(&xen_bridge_type_info);
type_register_static(&xen_bus_type_info);
type_register_static(&xen_device_type_info);
}
type_init(xen_register_types)
void xen_bus_init(void)
{
DeviceState *dev = qdev_create(NULL, TYPE_XEN_BRIDGE);
BusState *bus = qbus_create(TYPE_XEN_BUS, dev, NULL);
qdev_init_nofail(dev);
qbus_set_bus_hotplug_handler(bus, &error_abort);
}
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