[syslinux] mboot.c32, NUMA and tgz

[H. Peter Anvin]

Hansen, Timbonicus wrote:
> Hi all,
> 
> I'm attempting to PXE boot ESXi, which uses the syslinux mboot.c32 module. The mboot.c32 included with ESXi seems to be an older version that runs into an "out of memory loading.." problem halfway through, even though the box has 8GB memory. This may be related to NUMA, since it works fine on an older box but not the newer blade. I saw that some non-contiguous memory issues have been fixed in newer versions of syslinux and tried replacing the mboot.c32 with the 3.82 release, but now it seems to hang forever when loading a .tgz file.
> 
> Does mboot.c32 support tgz out of the box, or is this something VMware added in for ESXi? Do I need to recompile mboot or otherwise do something special to enable it? Is there a workaround for the previous memory issue?
> 

You can't just replace a .c32 file without replacing the core.

As far as .tgz is concerned, it would depend on what exactly VMware is
expecting to be done with the .tgz file.  Since the Multiboot spec
explicitly defers to the Grub implementation (not even saying which
version...), mboot.c32 mimics Grub behavior and will decompress a
compressed file, but it doesn't do anything special with the resulting
tarball.

As far as if VMware modified anything in ESXi, you'd have to ask VMware.
 Note that the old mboot.c32 was GPL, and so they should have to release
sources; the new mboot.c32 is MIT.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.