Re: [Xen-devel] Hypercall continuation and wait_event

[Ruslan Nikolaev <nruslan_devel@xxxxxxxxx>]

Thanks for the reply. 

Since it can take arbitrarily long for an event to arrive (e.g., it is coming 
from a different guest on a user request), how do I need to handle this 
case?Does it mean that I only need to make sure that nothings get scheduled on 
this VCPU in the guest?
Also, it is not exactly clear to me how wait_event avoids the need for 
hypercall continuation. What about local_events_need_delivery() or 
softirq_pending()? Are they going to be handled by wait_event internally?

Ruslan






----- Original Message -----
From: Keir Fraser <keir.xen@xxxxxxxxx>
To: Ruslan Nikolaev <nruslan_devel@xxxxxxxxx>; "xen-devel@xxxxxxxxxxxxx" 
<xen-devel@xxxxxxxxxxxxx>
Cc: 
Sent: Monday, April 9, 2012 6:54 PM
Subject: Re: [Xen-devel] Hypercall continuation and wait_event

On 09/04/2012 18:51, "Ruslan Nikolaev" <nruslan_devel@xxxxxxxxx> wrote:

> Hi
> 
> I am curious how I can properly support hypercall continuation and wait_event.
> I have a dedicated VCPU in a domain which makes a special hypercall, and the
> hypercall waits for certain event to arrive. I am using queues available in
> Xen, so wait_event will be invoked in the hypercall once its ready to accept
> events. However, my understanding that even though I have a dedicated VCPU for
> this hypercall, I still may need to support hypercall continuation properly.
> (Is this the case?) So, my question is how exactly the need for hypercall

No it's not the case, the old hypercall_create_continuation() mechanism does
not need to be used with wait_event().

-- Keir

> preemption may affect wait_event() and wait() operations, and where would I
> need to do hypercall_preempt_check()?
> 
> Thank you!
> Ruslan
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel