Re: [PATCH v3 2/3] hvc_init(): Enforce one-time initialization.

[Amit Shah]

On (Tue) 06 Dec 2011 [09:05:38], Miche Baker-Harvey wrote:
> Amit,
> 
> Ah, indeed.  I am not using MSI-X, so virtio_pci::vp_try_to_find_vqs()
> calls vp_request_intx() and sets up an interrupt callback.  From
> there, when an interrupt occurs, the stack looks something like this:
> 
> virtio_pci::vp_interrupt()
>   virtio_pci::vp_vring_interrupt()
>     virtio_ring::vring_interrupt()
>       vq->vq.callback()  <-- in this case, that's virtio_console::control_intr()
>         workqueue::schedule_work()
>           workqueue::queue_work()
>             queue_work_on(get_cpu())  <-- queues the work on the current CPU.
> 
> I'm not doing anything to keep multiple control message from being
> sent concurrently to the guest, and we will take those interrupts on
> any CPU. I've confirmed that the two instances of
> handle_control_message() are occurring on different CPUs.

Hi Miche,

Here's a quick-and-dirty hack that should help.  I've not tested this,
and it's not yet signed-off-by.  Let me know if this helps.