Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751986AbbEYIid (ORCPT ); Mon, 25 May 2015 04:38:33 -0400 Received: from www.linutronix.de ([62.245.132.108]:48323 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750859AbbEYIi2 (ORCPT ); Mon, 25 May 2015 04:38:28 -0400 Date: Mon, 25 May 2015 10:38:21 +0200 (CEST) From: Thomas Gleixner To: Feng Wu cc: joro@8bytes.org, dwmw2@infradead.org, jiang.liu@linux.intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [v7 4/8] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts In-Reply-To: <1432531734-25978-5-git-send-email-feng.wu@intel.com> Message-ID: References: <1432531734-25978-1-git-send-email-feng.wu@intel.com> <1432531734-25978-5-git-send-email-feng.wu@intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1741 Lines: 46 On Mon, 25 May 2015, Feng Wu wrote: > We don't need to migrate the irqs for VT-d Posted-Interrupts here. > When 'pst' is set in IRTE, the associated irq will be posted to > guests instead of interrupt remapping. The destination of the > interrupt is set in Posted-Interrupts Descriptor, and the migration > happens during vCPU scheduling. > > However, we still update the cached irte here, which can be used > when changing back to remapping mode. > > Signed-off-by: Feng Wu > Reviewed-by: Jiang Liu > Acked-by: David Woodhouse > --- > drivers/iommu/intel_irq_remapping.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c > index 1955b09..646f4cf 100644 > --- a/drivers/iommu/intel_irq_remapping.c > +++ b/drivers/iommu/intel_irq_remapping.c > @@ -994,7 +994,10 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask, > */ > irte->vector = cfg->vector; > irte->dest_id = IRTE_DEST(cfg->dest_apicid); > - modify_irte(&ir_data->irq_2_iommu, irte); > + > + /* We don't need to modify irte if the interrupt is for posting. */ > + if (irte->pst != 1) > + modify_irte(&ir_data->irq_2_iommu, irte); I don't think this is correct. ir_data->irte_entry contains the non posted version, which has pst == 0. You need some other way to store whether you are in posted mode or not. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/