From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:44539) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T4H9U-0007bC-NB for qemu-devel@nongnu.org; Wed, 22 Aug 2012 16:03:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T4H9T-0006Iu-6z for qemu-devel@nongnu.org; Wed, 22 Aug 2012 16:03:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61586) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T4H9S-0006If-Uk for qemu-devel@nongnu.org; Wed, 22 Aug 2012 16:03:43 -0400 Date: Wed, 22 Aug 2012 21:03:37 +0100 From: "Daniel P. Berrange" Message-ID: <20120822200337.GA9878@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Subject: [Qemu-devel] How to reliably start a bare QEMU target to query capabilities via QMP Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Anthony Liguori I've been adapting libvirt to use to the various new QMP commands to query QEMU's capabilities, instead of the hated -help parsing. Obviously the critical part of this is being able to reliably start a bare QEMU process with no actual guest OS configured (no disks, no kernel, etc) and talk to its monitor. I hadn't anticipated problems since I only tested with x86_64 / i386 most of the time, which work well in this respect. Currently I am doing # $QEMU_BINARY -S \ -no-user-config \ -nodefconfig \ -nodefaults \ -nographic \ -qmp stdio This works for about 50% of the QEMU targets: qemu-system-alpha qemu-system-i386 qemu-system-lm32 qemu-system-ppc qemu-system-ppc64 qemu-system-s390x qemu-system-sparc qemu-system-sparc64 qemu-system-x86_64 qemu-system-xtensa qemu-system-xtensaeb but fails for the other 50% of targets: qemu-system-arm qemu-system-cris qemu-system-m68k qemu-system-mips qemu-system-mips64 qemu-system-mips64el qemu-system-mipsel qemu-system-or32 qemu-system-ppcemb qemu-system-sh4 qemu-system-sh4eb qemu-system-unicore32 With the failing targets i see the following kinds of errors: $ qemu-system-arm -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Kernel image must be specified $ qemu-system-cris -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Kernel image must be specified $ qemu-system-m68k -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Kernel image must be specified $ qemu-system-mips -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait qemu: Could not load MIPS bios 'mips_bios.bin', and no -kernel argument was specified $ qemu-system-mipsel -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait qemu: Could not load MIPS bios 'mipsel_bios.bin', and no -kernel argument was specified $ qemu-system-or32 -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Can't create serial device, empty char device $ qemu-system-ppcemb -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Unable to find PowerPC CPU definition $ qemu-system-sh4 -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Initializing CPU Allocating ROM Allocating SDRAM 1 Allocating SDRAM 2 shix_init: load BIOS 'shix_bios.bin' ret=-1 qemu: could not load SHIX bios 'shix_bios.bin' $ qemu-system-sh4eb -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait Initializing CPU Allocating ROM Allocating SDRAM 1 Allocating SDRAM 2 shix_init: load BIOS 'shix_bios.bin' ret=-1 qemu: could not load SHIX bios 'shix_bios.bin' $ qemu-system-unicore32 -S -nodefconfig -nodefaults -nographic -qmp unix:/tmp/foo,server,nowait qemu-system-unicore32: /home/berrange/src/virt/qemu/hw/unicore32/../puv3.c:81: puv3_load_kernel: Assertion `kernel_filename != ((void *)0)' failed. Aborted Can we "fix" them in some way to not require the kernel ? Do we have to go down the route of adding some sort of "-no-vm" flag to explicitly say we don't care about any of the VM setup parts ? This would be more like what my old patches did which mapped monitors commands onto '-query-XXXXX' command line args, bypassing VM setup, but still using normal QMP monitor interaction. Any other suggestions on how to reliably get a QMP monitor to a target, without any VM config. ? Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|