2015-02-05 11:28:32 +01:00
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/*
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* watchdog device diag288 support
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*
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* Copyright IBM, Corp. 2015
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*
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* Authors:
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* Xu Wang <gesaint@linux.vnet.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or (at your
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* option) any later version. See the COPYING file in the top-level directory.
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*
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*/
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2016-01-26 19:17:00 +01:00
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#include "qemu/osdep.h"
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2019-08-12 07:23:38 +02:00
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#include "sysemu/reset.h"
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2015-02-05 11:28:32 +01:00
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#include "sysemu/watchdog.h"
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#include "qemu/timer.h"
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#include "hw/watchdog/wdt_diag288.h"
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2019-08-12 07:23:45 +02:00
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#include "migration/vmstate.h"
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2015-12-15 13:16:16 +01:00
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#include "qemu/log.h"
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2015-02-05 11:28:32 +01:00
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static WatchdogTimerModel model = {
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.wdt_name = TYPE_WDT_DIAG288,
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.wdt_description = "diag288 device for s390x platform",
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};
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2015-02-05 11:28:34 +01:00
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static const VMStateDescription vmstate_diag288 = {
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.name = "vmstate_diag288",
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.version_id = 0,
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.minimum_version_id = 0,
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.fields = (VMStateField[]) {
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VMSTATE_TIMER_PTR(timer, DIAG288State),
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VMSTATE_BOOL(enabled, DIAG288State),
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VMSTATE_END_OF_LIST()
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}
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};
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2015-02-05 11:28:32 +01:00
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static void wdt_diag288_reset(DeviceState *dev)
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{
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DIAG288State *diag288 = DIAG288(dev);
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diag288->enabled = false;
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timer_del(diag288->timer);
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}
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2015-06-29 08:21:10 +02:00
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static void diag288_reset(void *opaque)
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{
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DeviceState *diag288 = opaque;
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wdt_diag288_reset(diag288);
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}
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2015-02-05 11:28:32 +01:00
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static void diag288_timer_expired(void *dev)
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{
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qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
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2016-01-29 15:51:45 +01:00
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/* Reset the watchdog only if the guest gets notified about
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* expiry. watchdog_perform_action() may temporarily relinquish
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* the BQL; reset before triggering the action to avoid races with
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* diag288 instructions. */
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2016-01-19 08:45:19 +01:00
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switch (get_watchdog_action()) {
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2017-09-07 10:05:25 +02:00
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case WATCHDOG_ACTION_DEBUG:
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case WATCHDOG_ACTION_NONE:
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case WATCHDOG_ACTION_PAUSE:
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2016-01-29 15:51:45 +01:00
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break;
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default:
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wdt_diag288_reset(dev);
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2016-01-19 08:45:19 +01:00
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}
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2016-01-29 15:51:45 +01:00
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watchdog_perform_action();
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2015-02-05 11:28:32 +01:00
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}
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static int wdt_diag288_handle_timer(DIAG288State *diag288,
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uint64_t func, uint64_t timeout)
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{
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switch (func) {
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case WDT_DIAG288_INIT:
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diag288->enabled = true;
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/* fall through */
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case WDT_DIAG288_CHANGE:
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if (!diag288->enabled) {
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return -1;
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}
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timer_mod(diag288->timer,
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qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
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2016-03-21 17:02:30 +01:00
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timeout * NANOSECONDS_PER_SECOND);
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2015-02-05 11:28:32 +01:00
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break;
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case WDT_DIAG288_CANCEL:
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if (!diag288->enabled) {
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return -1;
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}
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diag288->enabled = false;
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timer_del(diag288->timer);
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break;
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default:
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return -1;
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}
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return 0;
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}
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static void wdt_diag288_realize(DeviceState *dev, Error **errp)
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{
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DIAG288State *diag288 = DIAG288(dev);
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2015-06-29 08:21:10 +02:00
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qemu_register_reset(diag288_reset, diag288);
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2015-02-05 11:28:32 +01:00
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diag288->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, diag288_timer_expired,
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dev);
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}
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qdev: Unrealize must not fail
Devices may have component devices and buses.
Device realization may fail. Realization is recursive: a device's
realize() method realizes its components, and device_set_realized()
realizes its buses (which should in turn realize the devices on that
bus, except bus_set_realized() doesn't implement that, yet).
When realization of a component or bus fails, we need to roll back:
unrealize everything we realized so far. If any of these unrealizes
failed, the device would be left in an inconsistent state. Must not
happen.
device_set_realized() lets it happen: it ignores errors in the roll
back code starting at label child_realize_fail.
Since realization is recursive, unrealization must be recursive, too.
But how could a partly failed unrealize be rolled back? We'd have to
re-realize, which can fail. This design is fundamentally broken.
device_set_realized() does not roll back at all. Instead, it keeps
unrealizing, ignoring further errors.
It can screw up even for a device with no buses: if the lone
dc->unrealize() fails, it still unregisters vmstate, and calls
listeners' unrealize() callback.
bus_set_realized() does not roll back either. Instead, it stops
unrealizing.
Fortunately, no unrealize method can fail, as we'll see below.
To fix the design error, drop parameter @errp from all the unrealize
methods.
Any unrealize method that uses @errp now needs an update. This leads
us to unrealize() methods that can fail. Merely passing it to another
unrealize method cannot cause failure, though. Here are the ones that
do other things with @errp:
* virtio_serial_device_unrealize()
Fails when qbus_set_hotplug_handler() fails, but still does all the
other work. On failure, the device would stay realized with its
resources completely gone. Oops. Can't happen, because
qbus_set_hotplug_handler() can't actually fail here. Pass
&error_abort to qbus_set_hotplug_handler() instead.
* hw/ppc/spapr_drc.c's unrealize()
Fails when object_property_del() fails, but all the other work is
already done. On failure, the device would stay realized with its
vmstate registration gone. Oops. Can't happen, because
object_property_del() can't actually fail here. Pass &error_abort
to object_property_del() instead.
* spapr_phb_unrealize()
Fails and bails out when remove_drcs() fails, but other work is
already done. On failure, the device would stay realized with some
of its resources gone. Oops. remove_drcs() fails only when
chassis_from_bus()'s object_property_get_uint() fails, and it can't
here. Pass &error_abort to remove_drcs() instead.
Therefore, no unrealize method can fail before this patch.
device_set_realized()'s recursive unrealization via bus uses
object_property_set_bool(). Can't drop @errp there, so pass
&error_abort.
We similarly unrealize with object_property_set_bool() elsewhere,
always ignoring errors. Pass &error_abort instead.
Several unrealize methods no longer handle errors from other unrealize
methods: virtio_9p_device_unrealize(),
virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
Much of the deleted error handling looks wrong anyway.
One unrealize methods no longer ignore such errors:
usb_ehci_pci_exit().
Several realize methods no longer ignore errors when rolling back:
v9fs_device_realize_common(), pci_qdev_unrealize(),
spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
virtio_device_realize().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-17-armbru@redhat.com>
2020-05-05 17:29:24 +02:00
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static void wdt_diag288_unrealize(DeviceState *dev)
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2015-02-05 11:28:32 +01:00
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{
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DIAG288State *diag288 = DIAG288(dev);
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timer_del(diag288->timer);
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timer_free(diag288->timer);
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}
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static void wdt_diag288_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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DIAG288Class *diag288 = DIAG288_CLASS(klass);
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dc->realize = wdt_diag288_realize;
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dc->unrealize = wdt_diag288_unrealize;
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dc->reset = wdt_diag288_reset;
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2017-08-16 16:08:48 +02:00
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dc->hotpluggable = false;
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2015-02-05 11:28:32 +01:00
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set_bit(DEVICE_CATEGORY_MISC, dc->categories);
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2015-02-05 11:28:34 +01:00
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dc->vmsd = &vmstate_diag288;
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2015-02-05 11:28:32 +01:00
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diag288->handle_timer = wdt_diag288_handle_timer;
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}
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static const TypeInfo wdt_diag288_info = {
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.class_init = wdt_diag288_class_init,
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.parent = TYPE_DEVICE,
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.name = TYPE_WDT_DIAG288,
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.instance_size = sizeof(DIAG288State),
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.class_size = sizeof(DIAG288Class),
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};
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static void wdt_diag288_register_types(void)
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{
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watchdog_add_model(&model);
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type_register_static(&wdt_diag288_info);
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}
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type_init(wdt_diag288_register_types)
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