From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp02.citrix.com ([66.165.176.63]:57203 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751180AbaJ0LJo (ORCPT ); Mon, 27 Oct 2014 07:09:44 -0400 Message-ID: <544E27F6.8010607@citrix.com> Date: Mon, 27 Oct 2014 11:09:42 +0000 From: David Vrabel MIME-Version: 1.0 To: Yijing Wang , Bjorn Helgaas CC: , , David Vrabel Subject: Re: [Xen-devel] [PATCH 1/3] x86/xen: Introduce a global flag to fix the MSI mask bug References: <1414377878-23497-1-git-send-email-wangyijing@huawei.com> <1414377878-23497-2-git-send-email-wangyijing@huawei.com> In-Reply-To: <1414377878-23497-2-git-send-email-wangyijing@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Sender: linux-pci-owner@vger.kernel.org List-ID: On 27/10/14 02:44, Yijing Wang wrote: > Commit 0e4ccb1505a9 ("PCI: Add x86_msi.msi_mask_irq() and msix_mask_irq()") > fixed MSI mask bug which may cause kernel crash. But the commit > made MSI code complex. Introduce a new global flag "pci_msi_ignore_mask" > to ignore MSI/MSI-X to fix this issue, it's a cleaner solution. > And the commit 0e4ccb1505a9 will be reverted in the later patch. Reviewed-by: David Vrabel In the sense that it keeps the odd Xen behaviour. But... Konrad, why was this fixed like this in the first place? IMO, it would have been better to get Xen to trap-and-emulate accesses to the relevant MSI/MSI-X registers. The mask/unmask on setup/teardown isn't performance critical. David