From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:58072) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gjZlT-0000YB-IG for qemu-devel@nongnu.org; Tue, 15 Jan 2019 20:13:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gjZlO-0000UP-BE for qemu-devel@nongnu.org; Tue, 15 Jan 2019 20:13:03 -0500 Date: Wed, 16 Jan 2019 09:12:33 +0800 From: Wei Yang Message-ID: <20190116011233.GA10810@richard> Reply-To: Wei Yang References: <1888836717.9067.1547583207433.ref@mail.yahoo.com> <1888836717.9067.1547583207433@mail.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1888836717.9067.1547583207433@mail.yahoo.com> Subject: Re: [Qemu-devel] Devdax backend for vnvdimm not working List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kamal Kakri Cc: "qemu-devel@nongnu.org" , "qemu-discuss@nongnu.org" On Tue, Jan 15, 2019 at 08:13:27PM +0000, Kamal Kakri via Qemu-devel wrote: >Hi, > >I have a namespace (backed by real nvdimm h/w) configured in devdax mode: ># ndctl list -N -n namespace0.0 >[ >  { >    "dev":"namespace0.0", >    "mode":"devdax", >    "map":"dev", >    "size":16909336576, >    "uuid":"e5265c0a-d902-41ce-b1d1-87a78c358aa4", >    "chardev":"dax0.0" >  } >] > Above is your host configuration, right? > >When I try to configure my vm using "virsh" with something like this: >    >      >        /dev/dax0.0 >        2048 >        >      >      >        2097152 >        0 >      >      >     
>    > I am not familiar with virsh, while I guess align here is the parameter passed to qemu. Hmm... as I being told, the alignment should be 128M. > >I get an error while starting my vm: ># virsh start fox22vm >start: domain(optdata): fox22vm >start: found option : fox22vm >start: trying as domain NAME >error: Failed to start domain fox22vm >error: internal error: qemu unexpectedly closed the monitor: ftruncate: Invalid argument >2019-01-15T18:00:36.587467Z qemu-kvm: -object memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/dev/dax0.0,share=yes,size=2147483648: unable to map backing store for guest RAM: Invalid argument The error message here shows the error is caused by mmap for an invalid argument. Hmm... but I am not sure which one is incorrect. Usually I run qemu directly, here is a qemu command line which works at my side: qemu/x86_64-softmmu/qemu-system-x86_64 -machine pc,nvdimm \ -m 6G,slots=4,maxmem=128G -smp 8 --enable-kvm \ -drive file=/home/richard/guest/fedora29.img,format=raw -nographic \ -drive file=/home/richard/guest/project.img,format=raw \ -object memory-backend-file,id=mem1,share=on,mem-path=/dev/dax0.0,size=10G,align=128M \ -device nvdimm,id=nvdimm1,memdev=mem1,label-size=128k Maybe you can compare the difference between your virsh result to see the difference. > >I have tried to add "align unit" to my virsh xml but it does not seem to pass it onto qemu (as much as I can see from the qemu cmd line in the logs at /var/log/libvirt/qemu) > > >Can anyone pls hint as to what possibly could be the issue ? Is this alignment related or something else ? > >Here are my versions: ># virsh --version >4.5.0 >[root@fox22hv libexec]# /usr/libexec/qemu-kvm --version >QEMU emulator version 2.12.0 (qemu-kvm-rhev-2.12.0-18.el7_6.1) >Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers ># uname -a >Linux fox22hv 4.19.0-1.el7.elrepo.x86_64 #1 SMP Mon Oct 22 10:40:32 EDT 2018 x86_64 x86_64 x86_64 GNU/Linux > > > -- Wei Yang Help you, Help me