From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423804AbcFHJ5q (ORCPT ); Wed, 8 Jun 2016 05:57:46 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:3740 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1161914AbcFHJ5j (ORCPT ); Wed, 8 Jun 2016 05:57:39 -0400 X-IBM-Helo: d23dlp02.au.ibm.com X-IBM-MailFrom: xyjxie@linux.vnet.ibm.com X-IBM-RcptTo: kvm@vger.kernel.org;linux-kernel@vger.kernel.org;linux-pci@vger.kernel.org Subject: Re: [RESEND PATCH v2 0/6] vfio-pci: Add support for mmapping MSI-X table To: Auger Eric , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org References: <1464847803-22756-1-git-send-email-xyjxie@linux.vnet.ibm.com> Cc: alex.williamson@redhat.com, bhelgaas@google.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, joro@8bytes.org, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, eric.auger@linaro.org, will.deacon@arm.com, gwshan@linux.vnet.ibm.com, alistair@popple.id.au, ruscur@russell.cc, kevin.tian@intel.com, David.Laight@ACULAB.COM From: Yongji Xie Date: Wed, 8 Jun 2016 17:56:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16060809-0016-0000-0000-000001A34B55 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16060809-0017-0000-0000-000004C97D8E Message-Id: <8ccf0165-da3e-9709-6cf2-ccab82eb55fb@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-08_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606080117 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Eric On 2016/6/8 15:41, Auger Eric wrote: > Hi Yongji, > > Le 02/06/2016 à 08:09, Yongji Xie a écrit : >> Current vfio-pci implementation disallows to mmap the page >> containing MSI-X table in case that users can write directly >> to MSI-X table and generate an incorrect MSIs. >> >> However, this will cause some performance issue when there >> are some critical device registers in the same page as the >> MSI-X table. We have to handle the mmio access to these >> registers in QEMU emulation rather than in guest. >> >> To solve this issue, this series allows to expose MSI-X table >> to userspace when hardware enables the capability of interrupt >> remapping which can ensure that a given PCI device can only >> shoot the MSIs assigned for it. And we introduce a new bus_flags >> PCI_BUS_FLAGS_MSI_REMAP to test this capability on PCI side >> for different archs. >> >> The patch 3 are based on the proposed patchset[1]. > You may have noticed I sent a respin of [1] yesterday: > http://www.gossamer-threads.com/lists/linux/kernel/2455187. > > Unfortunately you will see I removed the patch defining the new > msi_domain_info MSI_FLAG_IRQ_REMAPPING flag you rely on in this series. > I did so because I was not using it anymore. At the beginning this was > used to detect whether the MSI assignment was safe but this > method was covering cases where the MSI controller was > upstream to the IOMMU. So now I rely on a mechanism where MSI controller > are supposed to register their MSI doorbells and tag whether it is safe. > > I don't know yet how this change will be welcomed though. Depending > on reviews/discussions, might happen we revert to the previous flag. > > If you need the feature you can embed the used patches in your series and > follow the review process separately. Sorry for the setback. Thanks for your notification. I'd better wait until your patches get settled. Then I could exactly know which way we should use to test the capability of interrupt remapping on ARM in my series. Thanks, Yongji