From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH 7/8] evtchn: add FIFO-based event channel ABI Date: Wed, 20 Mar 2013 13:38:58 +0000 Message-ID: <5149BBF2.70505@citrix.com> References: <1363726818-25409-1-git-send-email-david.vrabel@citrix.com> <1363726818-25409-8-git-send-email-david.vrabel@citrix.com> <51499E3202000078000C7197@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51499E3202000078000C7197@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: "Keir (Xen.org)" , Konrad Rzeszutek Wilk , Wei Liu , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 20/03/13 10:32, Jan Beulich wrote: >>>> On 19.03.13 at 22:00, David Vrabel wrote: >> From: David Vrabel >> >> Add the event channel hypercall sub-ops and the definitions for the >> shared data structures for the FIFO-based event channel ABI. >> >> The design document for this new ABI is available here: >> >> http://xenbits.xen.org/people/dvrabel/event-channels-C.pdf >> >> In summary, events are reported using a per-domain shared event array >> of event words. Each event word has PENDING, LINKED and MASKED bits >> and a LINK field for pointing to the next event in the event queue. >> >> There are 16 event queues (with different priorities) per-VCPU. >> >> Key advantages of this new ABI include: >> >> - Support for over 100,000 events (2^17). > > As said in a comment on the design doc B, I'm missing a way for > the guest to learn the width of the involved mask (17 here, but > obviously there is nothing preventing this from being 16, 18, or > yet some other implementation specific value <= 29). I haven't forgotten this. I was focusing on the core implementation so not all the design review feedback has been incorporated yet. David