This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


RE: [Xen-devel] Question about evtchn_callback reentry

To: "Keir Fraser" <keir@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Question about evtchn_callback reentry
From: "Xu, Anthony" <anthony.xu@xxxxxxxxx>
Date: Wed, 20 Dec 2006 18:08:02 +0800
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 20 Dec 2006 02:08:41 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcciZU0dbGSEqQXwQrycerXX2pFPWAAIgEAJAAAfzJAAA9BF0QAE0ffJAE4l/cAAC5FSoQADF8yg
Thread-topic: [Xen-devel] Question about evtchn_callback reentry
Keir Fraser write on 2006年12月20日 16:31:
> On 20/12/06 3:03 am, "Xu, Anthony" <anthony.xu@xxxxxxxxx> wrote:
> How did you implement nesting avoidance? It'll be a bit subtle to get
> right. 

I added another global_event_mask in share page.

1. before injecting to event_callback_handler, set global_event_mask to 1 to 
   disable event inject..
2. after event_callback_handler is executed, it will return to ia64_leave_kernel
    assembly code in dom0, in this assembly code, it sets global_event_mask to 0
    to enable event inject.

There is no other code operating the global_event_mask.
Global_event_mask is initiated to 0(unmask).

Only global_event_mask is 0 and vcpu->vcpu_info->evtchn_upcall_mask is 0,
Can XEN injects to event_callback_handler of dom0.


>  -- Keir

Xen-devel mailing list