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

[Juan Quintela <quintela@redhat.com>]

Igor Mammedov <imammedo@redhat.com> wrote:
> On Thu, 23 Mar 2017 21:50:24 +0100
> Juan Quintela <quintela@redhat.com> 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");
> s/device_add/device_del/
>
>
> I'd put this check after "if (!dc->hotpluggable)" block, so error
> message won't hide wrong upluggable device error cases

Thanks.

I did both changes.  Not sure yet what *should* came 1st:
- device is not plugable/unplugable
- you can't do it while on migration

But I don't care, and as you seemed to preffer that other way, changed.

Later, Juan.

>> +        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.
>> @@ -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;
>> +    }
> the same here, do it right before "/* create device */"
>
>>      driver = qemu_opt_get(opts, "driver");
>>      if (!driver) {
>>          error_setg(errp, QERR_MISSING_PARAMETER, "driver");