From mboxrd@z Thu Jan 1 00:00:00 1970 From: david.vrabel@citrix.com (David Vrabel) Date: Mon, 27 Jul 2015 11:02:03 +0100 Subject: [Xen-devel] [PATCH] xen/events: Support event channel rebind on ARM In-Reply-To: <1437845664-32098-1-git-send-email-julien.grall@citrix.com> References: <1437845664-32098-1-git-send-email-julien.grall@citrix.com> Message-ID: <55B6019B.20903@citrix.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 25/07/15 18:34, Julien Grall wrote: > Currently, the event channel rebind code is gated with the presence of > the vector callback. > > The virtual interrupt controller on ARM has the concept of per-CPU > interrupt (PPI) which allow us to support per-VCPU event channel. > Therefore there is no need of vector callback for ARM. > > Xen is already using a free PPI to notify the guest VCPU of an event. > Furthermore, the xen code initialization in Linux (see > arch/arm/xen/enlighten.c) is requesting correctly a per-CPU IRQ. > > Introduce new macro xen_support_evtchn_rebind to allow architecture > decide whether rebind an event is support or not. It will always return > 1 on ARM and keep the same behavior on x86. > > This is also allow us to drop the usage of xen_have_vector_callback > entirely in the ARM code. Reviewed-by: David Vrabel Provided you make xen_support_evtchn_rebind() an inline function. David From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754133AbbG0KCJ (ORCPT ); Mon, 27 Jul 2015 06:02:09 -0400 Received: from smtp.citrix.com ([66.165.176.89]:30323 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753149AbbG0KCH (ORCPT ); Mon, 27 Jul 2015 06:02:07 -0400 X-IronPort-AV: E=Sophos;i="5.15,552,1432598400"; d="scan'208";a="284638296" Message-ID: <55B6019B.20903@citrix.com> Date: Mon, 27 Jul 2015 11:02:03 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Julien Grall , CC: , , , Catalin Marinas , Will Deacon , , Ingo Molnar , David Vrabel , "H. Peter Anvin" , Boris Ostrovsky , Thomas Gleixner , Subject: Re: [Xen-devel] [PATCH] xen/events: Support event channel rebind on ARM References: <1437845664-32098-1-git-send-email-julien.grall@citrix.com> In-Reply-To: <1437845664-32098-1-git-send-email-julien.grall@citrix.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/07/15 18:34, Julien Grall wrote: > Currently, the event channel rebind code is gated with the presence of > the vector callback. > > The virtual interrupt controller on ARM has the concept of per-CPU > interrupt (PPI) which allow us to support per-VCPU event channel. > Therefore there is no need of vector callback for ARM. > > Xen is already using a free PPI to notify the guest VCPU of an event. > Furthermore, the xen code initialization in Linux (see > arch/arm/xen/enlighten.c) is requesting correctly a per-CPU IRQ. > > Introduce new macro xen_support_evtchn_rebind to allow architecture > decide whether rebind an event is support or not. It will always return > 1 on ARM and keep the same behavior on x86. > > This is also allow us to drop the usage of xen_have_vector_callback > entirely in the ARM code. Reviewed-by: David Vrabel Provided you make xen_support_evtchn_rebind() an inline function. David