[ipxe-devel] SRP booting linux, SRP volume with ISO stops seeing itself

[Michael Brown]

On 08/01/16 02:19, james harvey wrote:
> Before I keep going down the hole, let me make sure my plan isn't
> futile.  I want to make a diskless system, by having iPXE in my
> InfiniBand card's ROM, and being able to boot an Arch Linux Live ISO
> (custom built with srp kernel modules) exported as a SRP volume backed
> by the ISO, and install on other SRP volumes which are backed by LVM
> volumes.
>
> I have a real general idea of how the iPXE to kernel handoff works,
> through the iBFT (iSCSI Boot Firmware Table.)  Since I'm using SRP
> rather than iSCSI, is the iBFT still used?  If not, how does the SRP
> connection get handed off, with all the variables needed for an SRP
> connection?

There is an SRP boot firmware table constructed (the sBFT).  This is 
nominally documented at

   http://ipxe.org/srp/sbft

However, I'm not aware of any Linux userspace tools that are capable of 
parsing that structure.  It should be fairly easy to create such a tool, 
which would scan base memory for the sBFT signature, verify the 
checksum, extract the fields, and then write the relevant values into 
sysfs to initiate the connection.

I thought I had written such a tool back in 2009, but all I can find 
relating to it is the proposal document.  It seems to have been an 
abandoned project back then.

Michael