486er hangs on boot with iPXE floppy

[NiKiZe]

MultimediaMan: There is NE2000 drivers as well, but I think those needs to be built separately since there is no autodetection for them so can't be included in the normal ipxe binary.

If you are having issues with getting iPXE to run, then it might be easier to concentrate on that, no need to mention and risk confusing with the other stuff.

I would never use prebuilt version of iPXE from any distro since you never know how it was built which for one makes it harder to debug, also it is often just to old.

Please build the ipxe.fd image

Code:

make bin/ipxe.dsk

from sources yourself.
You can find latest prebuilt one at http://boot.ipxe.org/

Unfortunately I can confirm that this does not work on 486 with this:

Code:

qemu-system-x86_64 -cpu 486 -m 24 -fda bin/ipxe.dsk

To fix this edit src/config/local/general.h and add this

Code:

#undef TIVOLI_VMM_WORKAROUND

now you can build the latest version, and it will work on machines without MMX instructions, such as the 486.

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Below is just technical details on how I found this

After running git bisect between current master and an old version that I found working:

Quote:71560d185475117b10994d839afe059577e7768c is the first bad commit
Author: Michael Brown <mcb30@ipxe.org>
Date: Wed Apr 27 11:03:18 2016 +0100

[librm] Preserve FPU, MMX and SSE state across calls to virt_call()

So to get a working build for 486, this works:

Code:

git clone git://git.ipxe.org/ipxe.git
cd git
git checkout fe62f3c831
cd src
make bin/ipxe.dsk

Later TIVOLI_VMM_WORKAROUND was implemented to revert this behavior so that is the better way get it working on older CPUs