Re: fyi, Xen's EFI workarounds (/mapbs & efi=no-rs) on SuperMicro hardware; fixes solve 1/2 problems & SM responds that can't/won't fix their firmware

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Sat, Dec 05, 2015 at 12:54:56PM -0800, PGNet Dev wrote:
> On 12/05/2015 11:44 AM, Konrad Rzeszutek Wilk wrote:
> >>Two issues exist with the SuperMicro EFI
> >>
> >>	(1) firmware EFI mis-mapping causing Xen PANIC on restart
> >
> >Can you try 'reboot=acpi' ?
> >
> ...
> >>I.e., what combination of
> >>
> >>/mapbs
> >>efi=no-rs
> >>reboot=acpi
> >>
> >All? It should be on the Xen command line.
> 
> with /mapbs on the EFI exec line,
> 
> 	grep mapbs /boot/grub2/grub.cfg
> 		chainloader $cmdpath/xen-4.6.0_04-398.efi xen-4.6.0_04-398.efi config.1
> /mapbs
> 
> and on the Xen Cmd Line,
> 
> 	grep efi= /boot/efi/EFI/opensuse/xen-4.6.0_04-398.cfg
> 		options= dom0_mem=3072M,max:3072M ... loglvl=all guest_loglvl=all
> efi=no-rs reboot=acpi

> 
> not clear to me what effect, if any, the addition of 'reboot=acpi' and
> '/mapbs' has, relative to just 'efi=no-rs' has.


Are you by chance an lawyer? :-)

Try without /mapbs, efi=nr-rs and with reboot=acpi. That should use EFI routines
for everything (including reboot). Doing the 'reboot=acpi' will override
the reboot routine to only use the ACPI method.

Granted if you did 'efi=nr-rs' we bypass EFI altogether and use 'acpi' method.

My theory was that if use some EFI routines it inits the firmware enough
that ACPI reboot should work. But it may be that it is just not happy.

There is an extra patch you can try to determine if the failure is
due to us doing ExitBootServices and not using virtual addresses (which
for example is the reason that under Lenovo it goes haywire).

See attached patch (against staging). With that you would do:

xen.efi /noexitboot /mapbs

And you can try without 'efi=no-rs'.

However I am wondering - why are you using '/mapbs' ? What did it
help? (The combination of 'efi=no-rs' means you are in effect not
using _any_ EFI operations - so doing /mapbs is not needed).