Thanks!!!! I will surely follow as you guided. On Wed, Oct 6, 2010 at 5:45 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote: > On Wed, Oct 6, 2010 at 12:34 PM, devi thapa <devi.thapa@xxxxxxxxx> wrote: >> I am actually going only through net.c and in this module they >> haven't specified anywhere, where this value is coming from. > > In order to understand net.c it will be necessary to read other code > too. Make sure you have an environment that makes it easy to jump to > function and variable definitions and switch between source files. > For example, use ctags, cscope, or even Eclipse to navigate the kernel > source tree. > >> So, you mean that kernel vhost code is connected to QEMU userspace code. > > QEMU userspace makes use of the vhost interface. If you get stuck > understanding the kernel side, you can jump to the relevant place in > QEMU and see what userspace is doing. This will be useful especially > for the part of the code that sets up a vhost-net device. > >> I request to guide me in following the code. > > In order to understand the code, you need to put in the effort to dig > through the source for yourself. > > The strategy I follow is to read the code (you've already started with > the kernel vhost-net code). Much of it will be unclear on the first > pass. > > Now switch to QEMU and read the vhost code there. Patterns will > become clearer but there will still be unanswered questions. > > Go back to the kernel and study it again with the insight you've > gained from the userspace side. > > Iterate a few times. That's how I understand new systems. > > Some other ideas to try if you get stuck: > > 1. Check the virtio specification for details on vring and the > virtio-net device: > http://ozlabs.org/~rusty/virtio-spec/virtio-spec-0.8.9.pdf > > 2. Use strace to see how QEMU uses the vhost file descriptor. > > 3. Look at related code like the virtio-net guest driver, the tap > driver, KVM's ioeventfd and irqfd. > > Good luck! > > Stefan > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
