From: Dave Anderson <anderson@xxxxxxxxxx> Subject: Re: crash cannot work for the newest qemu's core Date: Thu, 28 Jun 2012 16:38:56 -0400 > > > ----- Original Message ----- >> At 06/22/2012 09:06 PM, Dave Anderson Wrote: >> > >> > >> > ----- Original Message ----- >> >> >> >> >> >> ----- Original Message ----- >> >>> Hi, all >> >>> >> >>> When I use crash to deal with the vmcore generated by 'vrish dump', >> >>> I meet the following error: >> >>> >> >>> crash: seek error: kernel virtual address: ffffffff8180f1e0 type: "cpu_possible_mask". >> >>> >> >>> When I specify '-d 8' to get more information, I found the following message: >> >>> >> >>> NOTE: KVM/QEMU CPU_SAVE_VERSION 12 is greater than supported version 9 >> >>> >> >>> So I guess crash does not support it now. Does anyone have plan to fix it? >> >>> >> >>> Thanks >> >>> Wen Congyang >> >> >> >> Hi Wen, >> >> >> >> Also, because of your familiarity with this area, I certainly invite you >> >> to take a look at this... ;-) >> >> >> >> Thanks, >> >> Dave >> > >> > Hi Wen, >> > >> > On a related note, what is the status with your "virsh dump-guest-memory" >> > replacement of "virsh dump"? The last I saw, it seemed like the qemu guys >> > finally seemed willing to accept it? >> >> dump-guest-memory is not a virsh's sub command. It is a qemu monitor command. >> The patches for qemu and libvirt have been merged into newest qemu/libvirt. > > OK, but now I'm confused... > > I was presuming that you could run the new "dump-guest-memory" command from > the KVM host, specifying a particular guest, and it will create an ELF vmcore > that the crash utility can read. But I don't know what the term "qemu monitor > command" means? Is it a command that can be executed from a shell command line? > > And will "virsh dump" still exist? And if so, why? > > Dave This is a patch set in libvirt side: https://www.redhat.com/archives/libvir-list/2012-June/msg00404.html In summary: - dump-guest-memory is a qemu monitor command, the protocol of which is explained in http://wiki.qemu.org/QMP. - To get ELF-formatted vmcore, we specify --memory-only option to virsh dump command, then virsh dump uses dump-guest-memory monitor command vir QMP protocol, instead of migrate monitor command. - Note that the default behaviour remains calling migrate command. BTW, we can call monitor commands using virsh qemu-monitor-command but they are restricted, according to this FAQ: - http://wiki.libvirt.org/page/FAQ#Can_I_connect_to_the_QEMU_monitor_with_libvirt.3F Also, this is helpful to know how virsh commands use qemu monitor commands: - http://wiki.libvirt.org/page/QEMUSwitchToLibvirt#Monitor_command_equivalence Thanks. HATAYAMA, Daisuke -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
