Re: [Qemu-devel] Adding another debug protocol

[Peter Cheung]

> Date: Wed, 14 Nov 2012 17:43:12 +0100
> From: address@hidden
> To: address@hidden
> CC: address@hidden; address@hidden
> Subject: Re: [Qemu-devel] Adding another debug protocol
>
> On 2012-11-14 17:28, Peter Cheung wrote:
> > hi Jan, you are the maintainer of the gdb server of qemu?
>
> Not formally. I'm heavily using it for kernel debugging for a couple of
> years. Therefore, I'm fixing and enhancing it from time to time.
>
> > I think if I can't create my debug protocol, it is not easy to adopt peter-bochs debugger to qemu, in peter-bochs, there are some features I think current gdb protocol doesn't care, such as profiling, kernel module monitoring, call graph history, real time address probeing.
> > I know qemu is made by a lots of people, seems not easy to convince everyone.
>
> A good general rule, not only in open source, is to at least try to fix
> existing infrastructure. If that fails provably, you can come up with a
> new version to replace or augment things.
>
> E.g., you didn't explain yet why the gdb protocol and our existing stub
> cannot be extended in a backward compatible way that allows your
> debugger to attach to it. That way not only your debugger (is it Windows
> hosted?) could benefit from the improvements but the whole (x86) gdb world.
>
> Jan
>
> PS: Please don't top-post, cite what you comment on.
>
> --
> Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
> Corporate Competence Center Embedded Linux
>

sorry the top-posting, hotmail and gmail just changed to top-post years ago.

In GDB protocol, they don't have a repeat command, when i do profiling my kernel, let's say 10 mins, i probably need to send 100,000 "s" command to gdb, i think this will slow down the qemu, this already happen.

In GDB, i don't know how to set a pbreakpoint (physical address), breakpoint (linear address). I guess gdb is natural to all cpu platforms, so they don't provide this x86-specified breakpoint setting.

If really not possible to add this feature, can we do it : i compile all my code into an .a file, and qemu dynamically load it? then i don't need to modify the qemu source.

thanks