diff options
Diffstat (limited to 'hw/xen/xen-bus.c')
| -rw-r--r-- | hw/xen/xen-bus.c | 187 |
1 files changed, 162 insertions, 25 deletions
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index 14881126ff..6861ce136e 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -48,6 +48,54 @@ static char *xen_device_get_frontend_path(XenDevice *xendev) 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); @@ -208,14 +256,26 @@ 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 = { @@ -230,8 +290,8 @@ static const TypeInfo xen_bus_type_info = { }, }; -static void xen_device_backend_printf(XenDevice *xendev, const char *key, - const char *fmt, ...) +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; @@ -287,6 +347,70 @@ 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); +} + +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 (i.e. the + * state is not Connected) then set the backend state to Closed. + */ + if (xendev->backend_state == XenbusStateClosing && + xendev->frontend_state != XenbusStateConnected) { + xen_device_backend_set_state(xendev, XenbusStateClosed); + } + + /* + * 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 a backend is not 'online' then the device should be destroyed. + */ + if (xendev->backend_online && + xendev->backend_state == XenbusStateClosed) { + xen_device_backend_set_state(xendev, XenbusStateInitWait); + } else if (!xendev->backend_online && + (xendev->backend_state == XenbusStateClosed || + xendev->backend_state == XenbusStateInitialising || + xendev->backend_state == XenbusStateInitWait || + xendev->backend_state == XenbusStateUnknown)) { + object_unparent(OBJECT(xendev)); + } +} + static void xen_device_backend_create(XenDevice *xendev, Error **errp) { XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev))); @@ -307,6 +431,27 @@ static void xen_device_backend_create(XenDevice *xendev, Error **errp) 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; } } @@ -315,6 +460,16 @@ 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; } @@ -331,8 +486,8 @@ static void xen_device_backend_destroy(XenDevice *xendev) } } -static void xen_device_frontend_printf(XenDevice *xendev, const char *key, - const char *fmt, ...) +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; @@ -350,8 +505,8 @@ 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, ...) +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; @@ -407,24 +562,6 @@ static void xen_device_frontend_changed(void *opaque) 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) @@ -824,9 +961,9 @@ static void xen_device_realize(DeviceState *dev, Error **errp) xendev->frontend_path); xen_device_backend_printf(xendev, "frontend-id", "%u", xendev->frontend_id); - xen_device_backend_printf(xendev, "online", "%u", 1); 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", |