Re: Xen Booting Problem on ARM Machine

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 19 Oct 2021, Julien Grall wrote:
> On 19/10/2021 13:04, Sai Kiran Kumar Reddy Y wrote:
> > Hi,
> > 
> > Thanks for your inputs. As you have mentioned, I tried to boot Xen directly
> > from EFI, thereby skipping GRUB. I made sure that kernel, xen.cfg and
> > ramdisk are on the first FAT partition. I still get "All 128 bootinfo
> > membanks exhausted error". The following link has my grub.cfg config. file
> > and also the snapshot of the error.
> > 
> > Link:
> > https://drive.google.com/drive/folders/1o7WT5oB7UsaZBeY5m4mWSidT5NalzvvJ?usp=sharing
> > <https://drive.google.com/drive/folders/1o7WT5oB7UsaZBeY5m4mWSidT5NalzvvJ?usp=sharing>
> > 
> > I feel that even with EFI bootloader, there's some issue with bootinfo mem
> > banks and it maynot be a bug in GRUB. Let me know your thoughts on this.
> 
> As I wrote a few weeks ago. Both issues ("mem banks exhausted" and "Cannot
> exit boot services") are meant to be non-fatal. So you should be able to
> continue booting Xen afterwards.
> 
> The fact you don't see any log seems to suggest that you didn't enable
> properly earlyprintk. Would you be able to post your xen/.config?

Just to add to what Julien wrote, the "Cannot exit boot services" error
is printed from here:

https://gitlab.com/xen-project/xen/-/blob/staging/xen/common/efi/boot.c#L1086

as you can see, the error is printed but the function should continue onward.


To enable earlyprintk, you need to rebuild Xen. Assuming you build on
x86:

# cd xen.git/xen
# export CROSS_COMPILE=/path/to/cross-compiler # you can skip this if you build 
on ARM
# export XEN_TARGET_ARCH=arm64
# make menuconfig
      --> Debugging Options --> Developer Checks
      --> Debugging Options --> Early printk

Then you select driver and base address of the UART