Re: [Qemu-devel] Question about qemu firmware configuration (fw_cfg) device

[Richard W.M. Jones]

On Mon, Jul 19, 2010 at 10:33:12AM +0300, Gleb Natapov wrote:
> On Mon, Jul 19, 2010 at 08:28:02AM +0100, Richard W.M. Jones wrote:
> > On Mon, Jul 19, 2010 at 09:23:56AM +0300, Gleb Natapov wrote:
> > > That what I am warring about too. If we are adding device we have to be
> > > sure such device can actually exist on real hw too otherwise we may have
> > > problems later.
> > 
> > I don't understand why the constraints of real h/w have anything to do
> > with this.  Can you explain?
> > 
> Each time we do something not architectural it cause us troubles later.

Can you explain more or point to some examples?  I really don't
understand what these troubles could be.  But I'm prepared to be
enlightened.

> So what about making initrd smaller? I remember managing two
> distribution in 64M flash in embedded project.

The distribution is the size that it is, because (a) it has to be
based on Fedora and because (b) it has to include a certain number of
programs.

The reason for (a) is so that we don't need to compile our own tools
and we can benefit from bug fixes from Fedora (and contribute bug
fixes back).  The reason for (b) is that we want to implement a rich
API[1], and having a rich API means we simply have to include many
binaries.

We're already doing a lot of minimization on the image[2], deleting
man pages, language files, etc., so the image mainly just contains
binaries and libraries and kernel modules, which we cannot get rid of
because of (b).  The original pre-minimization image is 600MB or so.

Rich.

[1] http://libguestfs.org/guestfs.3.html
[2] http://manpages.ubuntu.com/manpages/lucid/man8/febootstrap-minimize.8.html

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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