diff options
Diffstat (limited to 'hw/xen/xen-bus.c')
| -rw-r--r-- | hw/xen/xen-bus.c | 211 |
1 files changed, 209 insertions, 2 deletions
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index 843fda26a9..5e19592190 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -6,6 +6,8 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" +#include "qemu/uuid.h" #include "hw/hw.h" #include "hw/sysbus.h" #include "hw/xen/xen.h" @@ -59,6 +61,87 @@ 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_unrealize(BusState *bus, Error **errp) { XenBus *xenbus = XEN_BUS(bus); @@ -69,9 +152,33 @@ static void xen_bus_unrealize(BusState *bus, Error **errp) 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); @@ -92,6 +199,9 @@ static void xen_bus_realize(BusState *bus, Error **errp) 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); return; fail: @@ -139,8 +249,25 @@ static void xen_device_backend_printf(XenDevice *xendev, const char *key, } } -static void xen_device_backend_set_state(XenDevice *xendev, - enum xenbus_state state) +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)); @@ -155,6 +282,11 @@ static void xen_device_backend_set_state(XenDevice *xendev, 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_create(XenDevice *xendev, Error **errp) { XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev))); @@ -218,6 +350,23 @@ static void xen_device_frontend_printf(XenDevice *xendev, const char *key, } } +static 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) { @@ -234,6 +383,50 @@ static void xen_device_frontend_set_state(XenDevice *xendev, 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 (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: "); + } + } + + /* + * If a backend is still 'online' then its state should be cycled + * back round to InitWait in order for a new frontend instance to + * connect. This may happen when, for example, a frontend driver is + * re-installed or updated. + */ + if (xendev->backend_state == XenbusStateClosed) { + unsigned int online; + + if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) { + online = 0; + } + + if (online) { + xen_device_backend_set_state(xendev, XenbusStateInitWait); + } + } +} + static void xen_device_frontend_create(XenDevice *xendev, Error **errp) { XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev))); @@ -254,6 +447,15 @@ static void xen_device_frontend_create(XenDevice *xendev, Error **errp) 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: "); } } @@ -262,6 +464,11 @@ 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; } |