From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: [PATCH V2] firmware: Change level-triggered GPE
 event to a edge one for qemu-xen
Date: Fri, 13 Dec 2013 17:32:37 +0000
Message-ID: <21163.17589.902931.334824@mariner.uk.xensource.com>
References: <1386613837-27399-1-git-send-email-anthony.perard@citrix.com>
	<1386862205-17863-1-git-send-email-anthony.perard@citrix.com>
	<52AB02C7020000780010CF98@nat28.tlf.novell.com>
	<20131213171157.GX10855@perard.uk.xensource.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta3.messagelabs.com ([195.245.230.39])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <Ian.Jackson@citrix.com>) id 1VrWbT-00014f-ID
	for xen-devel@lists.xenproject.org; Fri, 13 Dec 2013 17:32:43 +0000
In-Reply-To: <20131213171157.GX10855@perard.uk.xensource.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Anthony PERARD <anthony.perard@citrix.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>, Stefano Stabellini <stefano.stabellini@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, Jan Beulich <JBeulich@suse.com>
List-Id: xen-devel@lists.xenproject.org

Anthony PERARD writes ("Re: [PATCH V2] firmware: Change level-triggered GPE event to a edge one for qemu-xen"):
> For why qemu-xen-traditional doesn't not need this:
>   - a single `xl vcpu-set` can not trigger the race
> 
> For why qemu-xen-traditional doesn't not want this:
>   - avoid unnecessary change, especially in the ACPI table
> 
> About the PCI hotplug change and qemu-xen-traditional, I actually don't
> know what would be the effect.
> 
> Why qemu-xen-traditional would like this change for vcpu only:
>   - we might hit the race window via several consecutive `xl vcpu-set`
>     calls, or via direct change of xenstore entries.
> but after few try, I could not manage to have a missing cpu hotplug
> event.

I think this suggests to me that we should take this patch.  There's
no point leaving races sitting there to bite people, even if we think
they're theoretical.

Ian.