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

[Jason Wang <jasowang@redhat.com>]

在 2021/4/8 下午1:51, Dongli Zhang 写道:
>
> On 4/6/21 7:20 PM, Jason Wang wrote:
>> 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
> I will try if to add to "info pci" (introduce new arg option to "info pci"), or
> to introduce new command.


It's better to just reuse "info pci".


>
> About the EventNotifier, I will classify them as guest notifier or host notifier
> so that it will be much more easier for user to tell if the eventfd is for
> injecting IRQ or kicking the doorbell.


Sounds good.


>
> Thank you very much for all suggestions!
>
> Dongli Zhang


Thanks


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