From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758060Ab2EURdj (ORCPT ); Mon, 21 May 2012 13:33:39 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:20201 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756808Ab2EURdh (ORCPT ); Mon, 21 May 2012 13:33:37 -0400 Date: Mon, 21 May 2012 13:27:03 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] xen: do not map the same GSI twice Message-ID: <20120521172703.GA9988@phenom.dumpdata.com> References: <1337615650-27911-1-git-send-email-stefano.stabellini@eu.citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1337615650-27911-1-git-send-email-stefano.stabellini@eu.citrix.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 21, 2012 at 04:54:10PM +0100, Stefano Stabellini wrote: > PV on HVM guests map GSIs into event channels; at restore time the > event channels are resumed by restore_pirqs. > Device drivers might try to register the same GSI again through ACPI at > restore time, but the GSI has already been mapped and bound by > restore_pirqs. Which means... what kind of error do we get without this patch? > This patch detects these situations and avoid mapping the same GSI > multiple times. > > Signed-off-by: Stefano Stabellini > --- > arch/x86/pci/xen.c | 4 ++++ > drivers/xen/events.c | 5 +++-- > include/xen/events.h | 3 +++ > 3 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c > index 7415aa9..56ab749 100644 > --- a/arch/x86/pci/xen.c > +++ b/arch/x86/pci/xen.c > @@ -64,6 +64,10 @@ static int xen_register_pirq(u32 gsi, int gsi_override, int triggering, > int shareable = 0; > char *name; > > + irq = xen_irq_from_gsi(gsi); > + if (irq > 0) > + return irq; > + > if (set_pirq) > pirq = gsi; > > diff --git a/drivers/xen/events.c b/drivers/xen/events.c > index 0a8a17c..6908e4c 100644 > --- a/drivers/xen/events.c > +++ b/drivers/xen/events.c > @@ -611,7 +611,7 @@ static void disable_pirq(struct irq_data *data) > disable_dynirq(data); > } > > -static int find_irq_by_gsi(unsigned gsi) > +int xen_irq_from_gsi(unsigned gsi) > { > struct irq_info *info; > > @@ -625,6 +625,7 @@ static int find_irq_by_gsi(unsigned gsi) > > return -1; > } > +EXPORT_SYMBOL_GPL(xen_irq_from_gsi); > > /* > * Do not make any assumptions regarding the relationship between the > @@ -644,7 +645,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi, > > mutex_lock(&irq_mapping_update_lock); > > - irq = find_irq_by_gsi(gsi); > + irq = xen_irq_from_gsi(gsi); > if (irq != -1) { > printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n", > irq, gsi); > diff --git a/include/xen/events.h b/include/xen/events.h > index 0f77370..b332bd7 100644 > --- a/include/xen/events.h > +++ b/include/xen/events.h > @@ -103,6 +103,9 @@ int xen_irq_from_pirq(unsigned pirq); > /* Return the pirq allocated to the irq. */ > int xen_pirq_from_irq(unsigned irq); > > +/* Return the irq allocated to the gsi */ > +int xen_irq_from_gsi (unsigned gsi); > + > /* Determine whether to ignore this IRQ if it is passed to a guest. */ > int xen_test_irq_shared(int irq); > > -- > 1.7.2.5