On 05/07/2022 14:28, Rahul Singh wrote:
Hi Julien,
Hi Rahul,
On 28 Jun 2022, at 4:18 pm, Julien Grall <jul...@xen.org> wrote:
a new driver in linux kernel, etc where right now we just need to introduce an
extra IOCTL in linux to support this feature.
I don't understand why would need a new driver, etc. Given that you are introducing a new
IOCTL you could pass a flag to say "This is a static event channel so don't close
it".
I tried to implement other solutions to this issue. We can introduce a new
event channel state “ECS_STATIC” and set the
event channel state to ECS_STATIC when Xen allocate and create the static event
channels.
From what you wrote, ECS_STATIC is just an interdomain behind but where
you want Xen to prevent closing the port.
From Xen PoV, it is still not clear why this is a problem to let Linux
closing such port. From the guest PoV, there are other way to pass this
information (see below).
From guest OS we can check if the event channel is static (via
EVTCHNOP_status() hypercall ), if the event channel is
static don’t try to close the event channel. If guest OS try to close the
static event channel Xen will return error as static event channel can’t be
closed.
Why do you need this? You already need a binding indicating which ports
will be pre-allocated. So you could update your binding to pass a flag
telling Linux "don't close it".
I have already proposed that before and I haven't seen any explanation
why this is not a viable solution.
Cheers,
--
Julien Grall
