Date: Wed, 4 Nov 2015 13:50:15 +0000
From: "Richard W.M. Jones" <rjones@redhat.com>
To: Octavian Purdila <octavian.purdila@intel.com>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, thehajime@gmail.com
Subject: Re: [RFC PATCH 00/28] Linux Kernel Library
Message-ID: <20151104135015.GN29330@redhat.com>
References: <1446582059-17355-1-git-send-email-octavian.purdila@intel.com>
 <CAFLxGvzZozV0rDpY_VcQaFH+dx_+tHGyEy+22kgL=wdS5pSqCw@mail.gmail.com>
 <20151103224545.GI29330@redhat.com>
 <CAE1zotKa5B4xW5dzbrkGFcf7=ZTyVRLjvxnHtXV2nUzZ8HW_0g@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAE1zotKa5B4xW5dzbrkGFcf7=ZTyVRLjvxnHtXV2nUzZ8HW_0g@mail.gmail.com>
User-Agent: Mutt/1.5.20 (2009-12-10)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1977
Lines: 50

On Wed, Nov 04, 2015 at 01:24:03AM +0200, Octavian Purdila wrote:
> Thanks for the pointers Richard, I am going to take a look at it.

Now I've had a chance to look at some of the example LKL tools, here's
what this actually involves.  It's not actually a great deal of work,
it could probably be done in a day or two, but see my question about
`lkl_sys_*' below.

libguestfs (the library part) needs to talk over an RPC connection to
its daemon.  See diagram here:

http://libguestfs.org/guestfs-internals.1.html

The code in src/launch-{direct,libvirt,uml,...}.c sets up that
connection and runs the daemon -- normally inside a qemu wrapper, but
it could be inside UML.  For LKL I think it should just fork the
daemon directly.

The daemon would then be linked to LKL.

So really what's needed is a src/launch-lkl.c probably modelled after
one of these current backends:

https://github.com/libguestfs/libguestfs/blob/master/src/launch-uml.c
https://github.com/libguestfs/libguestfs/blob/master/src/launch-unix.c

and then recompile the daemon to link to LKL:

https://github.com/libguestfs/libguestfs/tree/master/daemon

and pass the list of disk images to the daemon, probably best to do
that on the guestfsd command line.

My only problem here: you can't just link to daemon to LKL, do you
have to change all of the system calls from `foo' to `lkl_sys_foo'?
That's an awful lot of #ifdefs ...

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/