[Qemu-devel] regarding codebase

[Qemu-devel] regarding codebase

[Shubham Kumar]

Sir

I'm having difficulty in understanding the codebase of QEMU .There seem to have hundreds of code files and header files in the directory and I'm unable to figure out the functionality of each file.Is there any way to understand the function of each file ??

Regards
Shubham Kumar 

Re: [Qemu-devel] regarding codebase

[Stefan Hajnoczi]

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On Fri, Feb 03, 2017 at 02:28:49AM +0530, Shubham Kumar wrote:
> I'm having difficulty in understanding the codebase of QEMU .There seem to have hundreds of code files and header files in the directory and I'm unable to figure out the functionality of each file.Is there any way to understand the function of each file ??

vl.c is the main() function for the qemu-system-* family of programs
(the "system emulators").  You could start exploring the source code
from there.  That's what I did when I first started hacking on QEMU.

Be prepared to read code.  QEMU isn't an educational codebase and the
code reflects the requirements of many contributors over the years.
Most of their requirements may not be relevant to you.  You will learn
to skip the stuff that doesn't affect you and to see the big picture.

If you have a specific area you are interested in, let us know and we
can tell you which source files are involved.

Stefan

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Re: [Qemu-devel] regarding codebase

[Eric Blake]

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On 02/03/2017 09:24 AM, Stefan Hajnoczi wrote:
> On Fri, Feb 03, 2017 at 02:28:49AM +0530, Shubham Kumar wrote:
>> I'm having difficulty in understanding the codebase of QEMU .There seem to have hundreds of code files and header files in the directory and I'm unable to figure out the functionality of each file.Is there any way to understand the function of each file ??
> 
> vl.c is the main() function for the qemu-system-* family of programs
> (the "system emulators").  You could start exploring the source code
> from there.  That's what I did when I first started hacking on QEMU.
> 
> Be prepared to read code.  QEMU isn't an educational codebase and the
> code reflects the requirements of many contributors over the years.
> Most of their requirements may not be relevant to you.  You will learn
> to skip the stuff that doesn't affect you and to see the big picture.

In fact, I seriously doubt ANYONE knows the entire code base.  Rather,
various people are experts in a subset of the code base; the MAINTAINERS
file is a good mapping of where to direct questions about a particular
file.  It's also a good jumping off point if you see a category that
interests you for knowing what files to inspect related to that category.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] regarding codebase

[Peter Maydell]

On 6 February 2017 at 19:51, Eric Blake <eblake@redhat.com> wrote:
> In fact, I seriously doubt ANYONE knows the entire code base.  Rather,
> various people are experts in a subset of the code base; the MAINTAINERS
> file is a good mapping of where to direct questions about a particular
> file.

...which means "mail the mailing list and cc the maintainer",
not "mail the maintainer only in private email", by the way.
Using the mailing lists helps to keep the information public
for others' benefit and means that anybody who happens to
know the answer can provide it.

thanks
-- PMM