Re: [Qemu-devel] Re: [RESEND][PATCH] gdbstub: Add vCont support

[Paul Brook <paul@codesourcery.com>]

>  a) Modeling cpus as processes buys us nothing compared to threads given
>     the fact that we cannot provide a stable memory mapping to the gdb
>     frontend anyway. (*)

I disagree. The process model fits perfectly. The whole point is that each CPU 
has its own virtual address space. Separate address spaces is the fundamental 
difference between a process and a thread.

If you have a multicore system where several cores share a MMU[1] then 
modelling these as threads probably make sense.

Don't confuse this with OS awareness in GDB (i.e. implementing a userspace 
debug environment via a bare metal kernel level debug interface). That's a 
completely separate issue.

>  b) The model is already part of mainline qemu. This patch is just
>     about adding even more usefulness to it.

I have no problems with ripping out the bogus "thread" support once (or even 
before) proper process support is implemented.  Likewise I've no problem 
requiring a recent GDB if you want to do multicore debugging.

Paul

[1] or have no MMU at all.