Re: [Qemu-devel] Suggested Wiki Update

[Thomas Huth <thuth@redhat.com>]

On 12.09.2017 13:18, Cornelia Huck wrote:
> On Tue, 12 Sep 2017 10:57:14 +0200
> Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> wrote:
> 
>> Hi,
>>
>> the content of https://wiki.qemu.org/index.php/Features/S390xNetworkBoot
>> is slightly outdated since proper DHCP based netboot support for s390x
>> has been implemented by the series ending with commit 29d1221.
>>
>> As it is still desirable to provide some instructions on building
>> network bootable images for the s390x architecture, I'd like to suggest
>> that the text is replaced (see proposal below). Conny, could I once more
>> request your help in that matter?
>>
>> == Building a s390 network bootable binary ==
>>
>> Since 2.10 QEMU offers network boot support which allows to load a
>> binary from a TFTP server and boot it. As s390 network bootable images
>> are not very common, this document gives a brief overview on how to
>> build one.
>>
>> A s390 network bootable image can be built by bundling some shell
>> scripts, busybox and the kexec binary bundled into an initial ramdisk
>> and append that to a kernel image. An existing s390 system can be used
>> as source.
>>
>> One way to do that is to take a kernel and an installer initial ramdisk
>> from a distribution's DVD/ISO and concatenate them. Some fixups are
>> necessary int the new binary, which can be done by using the script in
>> [https://github.com/ibm-s390-tools/s390-tools/blob/master/netboot/mk-s390image].
>> Booting this image would then start the installation process as if
>> booted from the DVD.
>>
>> Another possible way is to build a binary that behaves similar to the
>> PXELINUX boot loader. In this case an initial ramdisk with an init
>> process triggering the PXELINUX-like processing has to be built as
>> described in
>> [https://github.com/ibm-s390-tools/s390-tools/tree/master/netboot]. The
>> site also contains a script assisting in the creation of such an initial
>> ramdisk.
>>
> 
> Looks good.
> 
> Can you perhaps add a sentence that the base support is available with
> 2.9 and netboot with 2.10? ('Overview' looks like a good place for
> that.)

FWIW, I think it would also be good to add a sentence about the need to
specify "bootindex" somewhere (I remember trying to use "-boot n" the
first time I wanted to use it) ...

 Thomas