From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp02.au.ibm.com (e23smtp02.au.ibm.com [202.81.31.144]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qzW2r6snGzDt2r for ; Tue, 3 May 2016 16:09:08 +1000 (AEST) Received: from localhost by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 3 May 2016 16:09:07 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id D23CB2BB005B for ; Tue, 3 May 2016 16:09:03 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u4368tVL50594004 for ; Tue, 3 May 2016 16:09:03 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u4368TTb010646 for ; Tue, 3 May 2016 16:08:31 +1000 Subject: Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt remapping is supported To: "Tian, Kevin" , "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: <1461761010-5452-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1461761010-5452-6-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" , "David.Laight@ACULAB.COM" , "alistair@popple.id.au" , "ruscur@russell.cc" From: Yongji Xie Message-ID: Date: Tue, 3 May 2016 14:08:22 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2016/5/3 13:34, Tian, Kevin wrote: >> From: Yongji Xie >> Sent: Wednesday, April 27, 2016 8:43 PM >> >> This patch enables mmapping MSI-X tables if hardware supports >> interrupt remapping which can ensure that a given pci device >> can only shoot the MSIs assigned for it. >> >> With MSI-X table mmapped, we also need to expose the >> read/write interface which will be used to access MSI-X table. >> >> Signed-off-by: Yongji Xie > A curious question here. Does "allow to mmap MSI-X" essentially > mean that KVM guest can directly read/write physical MSI-X > structure then? > > Thanks > Kevin > Here we just allow to mmap MSI-X table in kernel. It doesn't mean all KVM guest can directly read/write physical MSI-X structure. This should be decided by QEMU. For PPC64 platform, we would allow to passthrough the MSI-X table because we know guest kernel would not write physical MSI-X structure when enabling MSI. Thanks, Yongji