Re: [libvirt-users] How does libvirt interaction with KVM to create a VM?

On 06/28/2012 06:26 PM, Daniel P. Berrange wrote: >The '/dev/kvm' device is the low level kernel interface for creating >virtual domains. This is not actually used by libvirt at all. The >QEMU binary has code that talks to /dev/kvm, so all libvirt does is >to spawn a QEMU process which in turns creates the virtual machine > >All the libvirt code for this part is under $GIT/src/qemu/ in particular >the qemu_command.c and qemu_process.c files > >Daniel Thanks Daniel, now I understand that the libvirt code will play with QEMU binary, for example, qemu-system-x86_64, the latter will talk with KVM module . But now the question is, I guess qemuProcessStart() function was used to spawn a QEMU process, so I built a virsh from the source package with "-g -O0" flag, I want to gdb the virsh, but when I want to set a break point on qemuProcessStart(), I encounter issue: #gdb virsh (gdb) b main Breakpoint 1 at 0x807d480: file virsh.c, line 20270. (gdb) r Starting program: /usr/bin/virsh [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1". Breakpoint 1, main (argc=1, argv=0xbffff294) at virsh.c:20270 20270 { (gdb) b qemuProcessStart Function "qemuProcessStart" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 2 (qemuProcessStart) pending. (gdb)c virsh # create guest.xml Domain vdo created from vdo.xml virsh # continue instruction above doesn't hit the pending Breakpoint 2... So my question is, which kind of object file will be created from $GIT/src/qemu folder during the build process, is it a .so file and virsh will load it?