Re: efinet SNP issue affects iscsi boot

[Daniel Kiper]

On Thu, Sep 20, 2018 at 06:38:07PM +0800, Michael Chang wrote:
> On Thu, Sep 13, 2018 at 06:06:15PM -0600, Micah Parrish wrote:
> > Hi, new subscriber here.? We have a problem with Grub 2 and its use of SNP
> > instead of MNP.? Our UEFI driver for a network card parses the relevant DHCP
> > options for iSCSI boot, generates an iBFT table, then gets closed by Grub
> > when it opens the SNP interface. The driver removes the iBFT table as part
> > of normal unload cleanup.? I think this should happen with the Tianocore
> > UEFI reference driver as well.? The problem is often masked or does not
> > occur when there are multiple network ports enabled.? It occurs with several
> > different vendors NICs.
> >
> > Possible solutions I see:
> >
> > 1. Grub parses the DHCP options and creates its own iBFT.
> >
> > 2. Grub copies the already generated iBFT before destroying the interface.
> >
> > 3. Grub opens the network interface MNP instead of SNP.
> >
> > Although I am a neophyte at grub and UEFI development, I would like to start
> > a discussion on possible solutions.? Has anyone else seen this?
>
> For possible solution 3, I managed to work out patch to use MNP but is not
> polished, although it survived my testing. If you don't mind and willing to
> give it go I will post it here as RFC patch for review.

That would be perfect. However, there are a few things worth mentioning here.

The issue is never ending story. So, please look for relevant discussions
in grub-devel archives and take them into account if it is possible/make sense.
If you have any difficulties with finding them drop me a line.

Please do not drop SNP driver. I think that we should make MNP driver a new
default and SNP should stay as a backup. Just in case.

Additionally, a few days ago I have started looking for people interested
in the project. There are some. Hence, if you are going to take a stab at
it I will ask them to do some reviews of your work. I will drop you their
emails if they are happy to do so.

Daniel