Re: [Qemu-devel] [PATCH 1/2] migration: Disable hotplug/unplug during migration

[Thomas Huth <thuth@redhat.com>]

On 23.03.2017 21:50, Juan Quintela wrote:
> Until we have reviewed what can/can't be hotplug during migration,
> disable it.  We can enable it later for the things that we know that
> work.  For instance, memory hotplug during postcopy don't work
> currently.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  hw/core/qdev.c | 5 +++++
>  qdev-monitor.c | 7 ++++++-
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 1e7fb33..8c4a3f3 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -277,6 +277,11 @@ void qdev_unplug(DeviceState *dev, Error **errp)
>      HotplugHandler *hotplug_ctrl;
>      HotplugHandlerClass *hdc;
>  
> +    if (!migration_is_idle()) {
> +        error_setg(errp, "device_add not allowed while migrating");
> +        return;
> +    }
> +
>      if (dev->parent_bus && !qbus_is_hotpluggable(dev->parent_bus)) {
>          error_setg(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
>          return;
> diff --git a/qdev-monitor.c b/qdev-monitor.c
> index 5f2fcdf..e0622b4 100644
> --- a/qdev-monitor.c
> +++ b/qdev-monitor.c
> @@ -29,7 +29,7 @@
>  #include "qemu/error-report.h"
>  #include "qemu/help_option.h"
>  #include "sysemu/block-backend.h"
> -
> +#include "migration/migration.h"
>  /*
>   * Aliases were a bad idea from the start.  Let's keep them
>   * from spreading further.

Maybe better keep an empty line between the include statement and the
comment?

 Thomas


> @@ -566,6 +566,11 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
>      BusState *bus = NULL;
>      Error *err = NULL;
>  
> +    if (!migration_is_idle()) {
> +        error_setg(errp, "device_add not allowed while migrating");
> +        return NULL;
> +    }
> +
>      driver = qemu_opt_get(opts, "driver");
>      if (!driver) {
>          error_setg(errp, QERR_MISSING_PARAMETER, "driver");
>