Re: [Qemu-devel] New Year's starting over ... bsd-user

[Sean Bruno]

On 01/04/17 11:32, Alex Bennée wrote:
> 
> Sean Bruno <address@hidden> writes:
> 
>> I'm pondering where to start with getting FreeBSD's bsd-user code into
>> shape so it could actually be reviewed and accepted now that its sort of
>> working again (signal handling fixed finally).
> 
> Also don't forget the parallel_cpus changes which were made for enhanced
> atomic support. There was also work in fixing up exclusive_start/end
> which is used for safe work like tb_flush.

Yeah, I ran head first into that wall last month.  :-)

We should be ok at this point as I've merged to master and am keeping up
now.

> 
>> I almost feel like the existing code should be purged, except that it
>> gives a good history (and this seems lazy to me).
>>
>> As a first pass, I guess, I'd like to at least make i386 user run on
>> x86_64.  What would you folks like to see in a first pass?
> 
> One thing that bugs me about linux-user is the amount of copy&paste
> repetition that goes on for the main run loop. Perhaps with a clean-up
> of the unused BSD architectures we could explore how a re-factored
> run loop could look with a view to moving to common run-loop code across
> both?

The bsd-user code does not have that nearly as much.  Hardware
architectures have been moved to seperate dirs and o/s support has been
broken up into seperate dirs.  This has made maintenance and testing
much easier, but not easy enough to get the code into your folk's tree.  :-)

> 
> Apart from syscall mapping and backend calls to the BSD ABI what
> differences are there between the two user-mode implementations?
> 

Not a substantial amount, IMO.  The setup and tear down are a bit
different, signal handling is a bit different, and as you mention
syscall mapping/backend calls are different.

>>
>> sean
>>
>> ref: https://github.com/seanbruno/qemu-bsd-user/tree/bsd-user
> 
> 
> --
> Alex Bennée
>

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