From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:37797) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gje5J-0002pL-Fy for qemu-devel@nongnu.org; Wed, 16 Jan 2019 00:49:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gje5F-00087r-7M for qemu-devel@nongnu.org; Wed, 16 Jan 2019 00:49:50 -0500 Date: Wed, 16 Jan 2019 13:49:31 +0800 From: Yi Zhang Message-ID: <20190116054930.GB73677@tiger-server> References: <1888836717.9067.1547583207433.ref@mail.yahoo.com> <1888836717.9067.1547583207433@mail.yahoo.com> <2050085823.124754.1547592669568@mail.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2050085823.124754.1547592669568@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" , luyao.zhong@intel.com On 2019-01-15 at 22:51:09 +0000, Kamal Kakri via Qemu-devel wrote: > My devdax device is 2MB aligned so I dont think this is alignment related.# ndctl list -X -n namespace0.0 > [ >   { >     "dev":"namespace0.0", >     "mode":"devdax", >     "map":"dev", >     "size":16909336576, >     "uuid":"e5265c0a-d902-41ce-b1d1-87a78c358aa4", >     "daxregion":{ >       "id":0, >       "size":16909336576, >       "align":2097152,  -------------------------> >       "devices":[ >         { >           "chardev":"dax0.0", >           "size":16909336576 >         } >       ] >     } >   } > ] > > > I even tried to create vnvdimm of exact same size as my devdax namespace, thinking that it would not need to ftruncate in that case but I still get the same error: > # 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 > 2019-01-15T21:58:52.647221Z qemu-kvm: -object memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/dev/dax0.0,share=yes,size=16909336576: unable to map backing store for guest RAM: Invalid argument > > > Has anyone ever got devdax backed vnvdimm configured and working? > If yes then pls let me know what libvirt/qemu/kernel version you have used to get it working. > > Thanks. > On Tuesday, January 15, 2019, 3:13:27 PM EST, Kamal Kakri 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" >   } > ] > > > When I try to configure my vm using "virsh" with something like this: >     >       >         /dev/dax0.0 >         2048 this should be alignsize, Add Luyao. >         >       >       >         2097152 >         0 >       >       >      
>     > > > 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 > > 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 > > > > >