From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750930AbeECMYF (ORCPT ); Thu, 3 May 2018 08:24:05 -0400 Received: from 8bytes.org ([81.169.241.247]:53960 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752116AbeECMXt (ORCPT ); Thu, 3 May 2018 08:23:49 -0400 Date: Thu, 3 May 2018 14:23:46 +0200 From: Joerg Roedel To: Jagannathan Raman Cc: tglx@linutronix.de, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu/vt-d: fix usage of force parameter in intel_ir_reconfigure_irte() Message-ID: <20180503122346.nl3dovkyb3py3zpc@8bytes.org> References: <1520375981-4958-1-git-send-email-jag.raman@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1520375981-4958-1-git-send-email-jag.raman@oracle.com> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 06, 2018 at 05:39:41PM -0500, Jagannathan Raman wrote: > It was noticed that the IRTE configured for guest OS kernel > was over-written while the guest was running. As a result, > vt-d Posted Interrupts configured for the guest are not being > delivered directly, and instead bounces off the host. Every > interrupt delivery takes a VM Exit. > > It was noticed that the following stack is doing the over-write: > [ 147.463177] modify_irte+0x171/0x1f0 > [ 147.463405] intel_ir_set_affinity+0x5c/0x80 > [ 147.463641] msi_domain_set_affinity+0x32/0x90 > [ 147.463881] irq_do_set_affinity+0x37/0xd0 > [ 147.464125] irq_set_affinity_locked+0x9d/0xb0 > [ 147.464374] __irq_set_affinity+0x42/0x70 > [ 147.464627] write_irq_affinity.isra.5+0xe1/0x110 > [ 147.464895] proc_reg_write+0x38/0x70 > [ 147.465150] __vfs_write+0x36/0x180 > [ 147.465408] ? handle_mm_fault+0xdf/0x200 > [ 147.465671] ? _cond_resched+0x15/0x30 > [ 147.465936] vfs_write+0xad/0x1a0 > [ 147.466204] SyS_write+0x52/0xc0 > [ 147.466472] do_syscall_64+0x74/0x1a0 > [ 147.466744] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > > reversing the sense of force check in intel_ir_reconfigure_irte() > restores proper posted interrupt functionality > > Signed-off-by: Jagannathan Raman Applie, thanks.