Re: [PATCH 0/6] Add debug interface to kick/call on purpose

[Jason Wang <jasowang@redhat.com>]

在 2021/4/7 上午7:27, Dongli Zhang 写道:
>> This will answer your question that "Can it bypass the masking?".
>>
>> For vhost-scsi, virtio-blk, virtio-scsi and virtio-net, to write to eventfd is
>> not able to bypass masking because masking is to unregister the eventfd. To
>> write to eventfd does not take effect.
>>
>> However, it is possible to bypass masking for vhost-net because vhost-net
>> registered a specific masked_notifier eventfd in order to mask irq. To write to
>> original eventfd still takes effect.
>>
>> We may leave the user to decide whether to write to 'masked_notifier' or
>> original 'guest_notifier' for vhost-net.
> My fault here. To write to masked_notifier will always be masked:(


Only when there's no bug in the qemu.


>
> If it is EventNotifier level, we will not care whether the EventNotifier is
> masked or not. It just provides an interface to write to EventNotifier.


Yes.


>
> To dump the MSI-x table for both virtio and vfio will help confirm if the vector
> is masked.


That would be helpful as well. It's probably better to extend "info pci" 
command.

Thanks


>
> Thank you very much!
>
> Dongli Zhang
>