[Qemu-devel] Re: Unposted reserved_va patch

[Paul Brook <paul@codesourcery.com>]

> Re: 68a1c816868b3e35a1da698af412b29e61b1948a
> 
> In general, I like the idea (especially since I've proposed it before.  ;-)
> 
> However:
> 
> +        if (have_guest_base) {
> +            flags |= MAP_FIXED;
> +        }
> 
> I think this is broken.  If the user specifies -G n -R m they're hoping
> or guessing that the range [n,n+m) is free.  What they're not expecting
> is for the qemu application or any of the required shared libraries to
> get forcibly unmapped.
> 
> I think instead you should simply adjust the error reporting after the
> mmap attempt without MAP_FIXED.

Hmm, maybe. My reasoning was that this is consistent with the current behavior 
of the ELF loader.  If you specify -G then the target application will be 
splatted at that address, regardless of whether it's already used by the host.

Paul