[OpenPower-Firmware] [PATCH] skiroot_defconfig: Remove VirtIO and Solarflare

[Stewart Smith]

On Tue, Dec 8, 2020, at 12:21 PM, Klaus Heinrich Kiwi wrote:
> 
> 
> On 12/8/2020 12:02 AM, Joel Stanley wrote:
> > On Mon, 7 Dec 2020 at 20:28, Klaus Heinrich Kiwi
> > <klaus at linux.vnet.ibm.com> wrote:
> >>
> >> Remove drivers that apparently are not being used:
> >>    * Solarflare
> >>    * VirtIO-related drivers
> > 
> > nak, virtio is used for testing in qemu.
> > 
> Good point - although perhaps we could use e1000 and megasas without 
> any practical drawbacks?
> 
> At any rate, I'm looking for alternatives to keep our zImage.epapr 
> (with bundled rootfs)
> under 16MB - it is looking like this is desirable for maintaining 
> compatibility with
> AIX / IBM i "lids" constructs that have this as an upper limit.

The zz_defconfig will build a separate kernel and initramfs for this very reason. We long ago ended up needing greater than 16MB on FSP based boxes (even before the firmware there was built with buildroot), and we have the logic to load both LIDs in skiboot, and this is what's done.

It's only "kinda handy for a developer" to copy the one file across.

(*Unless something has changed in the past 18 months)

So it's really only the initramfs itself getting greater than 16MB which could pose a problem there.

However, for OpenPOWER, it's 16MB.

I've long been a proponent of going down the route of splitting it up on OpenPOWER and having the initramfs instead be a mtd device that can load things on demand rather than block booting for a further nearly 10 seconds while it reads the initramfs over LPC. However, somebody has to actually do that work :)

> Looking for things that we might not care about on Skiroot (anymore) 
> plus the fact that
> retired Power8 support, some thoughts are:
> 
>    
>    * Chelsio T3 and T4 and QLogic NetXtreme II iSCSI support - not 
> aware of anyone shipping,
>      or even using this. Not having hardware offloading for iscsi 
> sounds hardly a blocker for
>      a bootloader, but I couldn't even find the iscsi initiator 
> userland configured.. so not
>      sure why we have this enabled?
>    * Alteon AceNIC/3Com 3C985/NetGear GA620 Gigabit support - mac G3 
> era legacy? Couldn't
>      find why we ever needed this on OpenPower
>    * QLogic bnx2 & CNIC support - looks like tg3 and bnx2x have been 
> the norm lately
>    * Myricom Myri-10G - not aware of anyone using it
>    * Neterion (Exar) Xframe 10Gb - same

There's https://open-power.github.io/op-build/boot-devices.html which should be updated as well.

> Other non-kernel choices might be:
>    * rsync - some 500KB shaved
>    * lrsz - 90kb
>    * netcat - 80kb

for lrsz:
https://www.flamingspork.com/blog/2017/10/20/zmodem-saves-the-day-or-why-my-firmware-for-a-machine-with-a-cpu-from-2017-contains-a-serial-file-transfer-protocol-from-the-1980s/

Damn useful getting binary debug data (or even text data when the BMC is crap and can't do a serial port without dropping data) off a box.