Jagannathan Raman <jag.ra...@oracle.com> writes:
> Add blocker to prevent hot-unplug of devices
Why do you need this? I'm not doubting you do, I just want to read your
reasons here :)
>
> Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com>
> Signed-off-by: John G Johnson <john.g.john...@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com>
> ---
> include/hw/qdev-core.h | 29 +++++++++++++++++++++++++++++
> hw/core/qdev.c | 24 ++++++++++++++++++++++++
> softmmu/qdev-monitor.c | 4 ++++
> 3 files changed, 57 insertions(+)
>
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 92c3d65208..1b9fa25e5c 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -193,6 +193,7 @@ struct DeviceState {
> int instance_id_alias;
> int alias_required_for_version;
> ResettableState reset;
> + GSList *unplug_blockers;
> };
>
> struct DeviceListener {
> @@ -419,6 +420,34 @@ void qdev_simple_device_unplug_cb(HotplugHandler
> *hotplug_dev,
> void qdev_machine_creation_done(void);
> bool qdev_machine_modified(void);
>
> +/*
> + * qdev_add_unplug_blocker: Adds an unplug blocker to a device
> + *
> + * @dev: Device to be blocked from unplug
> + * @reason: Reason for blocking
> + */
> +void qdev_add_unplug_blocker(DeviceState *dev, Error *reason);
> +
> +/*
> + * qdev_del_unplug_blocker: Removes an unplug blocker from a device
> + *
> + * @dev: Device to be unblocked
> + * @reason: Pointer to the Error used with qdev_add_unplug_blocker.
> + * Used as a handle to lookup the blocker for deletion.
> + */
> +void qdev_del_unplug_blocker(DeviceState *dev, Error *reason);
> +
> +/*
> + * qdev_unplug_blocked: Confirms if a device is blocked from unplug
> + *
> + * @dev: Device to be tested
> + * @reason: Returns one of the reasons why the device is blocked,
> + * if any
> + *
> + * Returns: true if device is blocked from unplug, false otherwise
> + */
> +bool qdev_unplug_blocked(DeviceState *dev, Error **errp);
> +
> /**
> * GpioPolarity: Polarity of a GPIO line
> *
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 84f3019440..0806d8fcaa 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -468,6 +468,28 @@ char *qdev_get_dev_path(DeviceState *dev)
> return NULL;
> }
>
> +void qdev_add_unplug_blocker(DeviceState *dev, Error *reason)
> +{
> + dev->unplug_blockers = g_slist_prepend(dev->unplug_blockers, reason);
> +}
> +
> +void qdev_del_unplug_blocker(DeviceState *dev, Error *reason)
> +{
> + dev->unplug_blockers = g_slist_remove(dev->unplug_blockers, reason);
> +}
> +
> +bool qdev_unplug_blocked(DeviceState *dev, Error **errp)
> +{
> + ERRP_GUARD();
> +
> + if (dev->unplug_blockers) {
> + error_propagate(errp, error_copy(dev->unplug_blockers->data));
> + return true;
> + }
> +
> + return false;
> +}
This cites the most recently added blocker as reason. Your function
comment covers it: "Returns one of the reasons". Okay.
> +
> static bool device_get_realized(Object *obj, Error **errp)
> {
> DeviceState *dev = DEVICE(obj);
> @@ -704,6 +726,8 @@ static void device_finalize(Object *obj)
>
> DeviceState *dev = DEVICE(obj);
>
> + g_assert(!dev->unplug_blockers);
> +
> QLIST_FOREACH_SAFE(ngl, &dev->gpios, node, next) {
> QLIST_REMOVE(ngl, node);
> qemu_free_irqs(ngl->in, ngl->num_in);
> diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
> index 12fe60c467..9cfd59d17c 100644
> --- a/softmmu/qdev-monitor.c
> +++ b/softmmu/qdev-monitor.c
> @@ -898,6 +898,10 @@ void qdev_unplug(DeviceState *dev, Error **errp)
> HotplugHandlerClass *hdc;
> Error *local_err = NULL;
>
> + if (qdev_unplug_blocked(dev, errp)) {
> + return;
> + }
> +
> if (dev->parent_bus && !qbus_is_hotpluggable(dev->parent_bus)) {
> error_setg(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
> return;
