[syslinux] Chaining to pxelinux.0 6.0.3 from iPXE - ldlinux.c32

[Ady]

> > 
> > Now I have something I can reproduce.  Booting my same ipxe.iso to
> > perform an initial TFTP load shows what I saw already.  Attempting to
> > load a file via http results in an immediate error message with no
> > resulting traffic as far as I can see.
> > 
> 
> Very positive development...
> 
 
Regarding KVM (but also about HP), the way pxelinux.0 fails to get to 
the next step (ldlinux.c32) reminded me of other issues, mainly in the 
whole EFI+QEMU+OVMF+edk2 areas.

Remember the "Failed to read blocks: 0xC" email threads? (They span 
several months, since 2014Nov until 2015Aug.) Back then the point was 
that qemu and ipxe and the nic roms all needed certain updates / 
patches that were not yet included in their respective official sources 
/ releases. That was relevant for ipxe too.

While following a chain of links, I also stumbled upon issues with 
(newer) versions of glibc.

The glibc version matter I read reminded me (not immediately, but after 
some additional search I eventually found what I was trying to 
remember) that between 6.03-pre20 and the final 6.03 there was a 
glibc-related commit in Syslinux ("define _DEFAULT_SOURCE for 
glibc-2.20").

The reason this might be relevant here is because, back then, 
6.03-pre20 worked OK under QEMU+KVM+EFI under certain environments but 
6.03 did not. For an example:

 http://lukas.zapletalovi.com/2014/09/efi-in-qemu-kvm-on-fedora-20.html 


So, I cannot help but wonder whether there is not only some possible 
issue in Syslinux but also a matter of the virtual BIOS (SEABIOS) and 
the specific vitual NICs being chosen for these tests with pxelinux.0. 
Also, would there be any different behavior with official pre-built 
6.03-pre20 in the current case? Or perhaps building the current git 
head with a different glibc version? And what about newer "versions" 
(or building based on newer commits) of ipxe / KVM / QEMU / SEABIOS / 
virtual NICs?

I know, I know..., this is about pxelinux.0 + ldlinux.c32 and not about 
UEFI and I most probably have no idea what I am talking about, but...

Regards,
Ady.