Re: [PATCH] failover: unregister ram on unplug

[Laurent Vivier]

On 21/07/2021 12:41, Michael S. Tsirkin wrote:
> On Wed, Jul 21, 2021 at 10:58:17AM +0200, Igor Mammedov wrote:
>> On Tue, 20 Jul 2021 20:16:44 +0200
>> Laurent Vivier <lvivier@redhat.com> wrote:
>>
>>> This simple change allows to test failover with a simulated device
>>> like e1000e rather than a vfio device.
>>>
>>> This is interesting to developers that want to test failover on
>>> a system with no vfio device. Moreover it simplifies host networking
>>> configuration as we can use the same bridge for virtio-net and
>>> the other failover networking device.
>>>
>>> Without this change the migration of a system configured with failover
>>> fails with:
>>>
>>>   Unknown ramblock "0000:00:01.1:00.0/e1000e.rom", cannot accept migration
>>>   error while loading state for instance 0x0 of device 'ram'
>>>   load of migration failed: Invalid argument
>>>
>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>
>> Reviewed-by: Igor Mammedov <imammedo@redhat.com>
>>
>>> ---
>>>  hw/net/virtio-net.c | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>>> index 16d20cdee52a..8f7735bad4f2 100644
>>> --- a/hw/net/virtio-net.c
>>> +++ b/hw/net/virtio-net.c
>>> @@ -3256,6 +3256,9 @@ static void 
>>> virtio_net_handle_migration_primary(VirtIONet *n, MigrationState *s)
>>>      if (migration_in_setup(s) && !should_be_hidden) {
>>>          if (failover_unplug_primary(n, dev)) {
>>>              vmstate_unregister(VMSTATE_IF(dev), qdev_get_vmsd(dev), dev);
>>> +            if (PCI_DEVICE(dev)->has_rom) {
> 
> 
> Hmm. Any way to hide this behind an interface so
> we don't need to poke at pci device internals?

There is the pci_del_option_rom() but it's not exported.

Do you want I export and use it?

Thanks,
Laurent

> 
>>> +                vmstate_unregister_ram(&PCI_DEVICE(dev)->rom , dev);
>>> +            }
>>>              qapi_event_send_unplug_primary(dev->id);
>>>              qatomic_set(&n->failover_primary_hidden, true);
>>>          } else {
>