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

[Jason Wang]

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