From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yongji Xie Subject: Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt remapping is supported Date: Tue, 3 May 2016 14:08:22 +0800 Message-ID: References: <1461761010-5452-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1461761010-5452-6-git-send-email-xyjxie@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Cc: "alistair-Y4h6yKqj69EXC2x5gXVKYQ@public.gmane.org" , "nikunj-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org" , "zhong-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org" , "eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "aik-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org" , "mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org" , "ruscur-3Su/lFKaw5ejKv3TNrM5DQ@public.gmane.org" , "will.deacon-5wv7dgnIgG8@public.gmane.org" , "gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org" , "warrier-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org" , "David.Laight-ZS65k/vG3HxXrIkS9f7CXA@public.gmane.org" , "paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org" , "benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org" , "bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org" To: "Tian, Kevin" , "kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: kvm.vger.kernel.org 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