RE: Colibri imx8qxp: Missing kernel boot module

[Daniel Wagner2 <Daniel.Wagner2@xxxxxxxxxxxxxxxxxx>]

Hello Julien,

> >>>>>> On 10/08/2020 16:32, Daniel Wagner2 wrote:
> >>>>>>> Hello xen-users,
> >>>>>>> we are trying to get Xen running on a Toradex "Colibri iMX8X"
> >>>>>>> module (see [1] at the bottom of this email), which features the
> >>>>>>> iMX8 QXP
> >>>>> prozessor.
> >>>>>>> We found that NXP has a Xen reference implementation [2][3] for
> >>>>>>> their MEK Module and tried to port that to the Toradex
> > module.
> >>>>>>>
> >>>>>>> When booting via the bootscript [4], which is unaltered except
> >>>>>>> for the "dom0fdt_file" and "xenhyper_bootargs" variables, we get
> >>>>>>> the following
> >>>>>>> error:
> >>>>>>>
> >>>>>>> [...] (See [5] for complete bootlog)
> >>>>>>> (XEN) *** LOADING DOMAIN 0 ***
> >>>>>>> (XEN) Missing kernel boot module?
> >>>>>>> (XEN)
> >>>>>>> (XEN) ****************************************
> >>>>>>> (XEN) Panic on CPU 0:
> >>>>>>> (XEN) Could not set up DOM0 guest OS
> >>>>>>> (XEN) ****************************************
> >>>>>>> (XEN)
> >>>>>>> (XEN) Reboot in five seconds...
> >>>>>>>
> >>>>>>> For Dom0 we took the linux-toradex kernel source, ran "make
> >>> xenconfig"
> >>>>>>> [6], which should add Xen-support and rebuilt the Image with
> >>>>>>> "make
> >>>>> Image".
> >>>>>>> For dom0 DTB [7] we copied the dom0 DTS NXP uses for their
> >>>>> MEK-Module
> >>>>>>> [8] and only adjusted the "bootargs" parameter.
> >>>>>>> This Linux Image was able to run after we rebuilt and booted it
> >>>>>>> without
> >>>>> Xen.
> >>>>>>
> >>>>>> Which Device-Tree did you for boot Linux without Xen?
> >>>>>
> >>>>> Used the same Device-Tree Binary that we want to use with Xen
> >>>>> which is described in [7]. In [7] you can see rows 23 and 24,
> >>>>> which include the Devicetree as it is supplied by Toradex.
> >>>>> To boot linux with our dom0 DTB, the u-boot variable fdt_file was
> >>>>> changed from fsl-imx8qxp-colibri-eval-v3.dtb to
> >>>>> fsl-imx8qxp-colibri-eval-v3-dom0.dtb.
> >>>>
> >>>>
> >>>> Did you use the U-Boot cmd 'xenmmcboot' or 'xennetboot'?
> >>>
> >>> To boot linux without Xen the u-boot cmd 'boot' is used.
> >>> To boot Xen we use 'run xenmmcboot' (in an adjusted form to account
> >>> for different filenames and bootargs, see [4]).
> >>
> >> So kernel Image loaded to 0x80a00000, right?
> >>
> >> Please load kernel image before run xenmmcboot if not.
> >
> > The xenmmcboot script [4] line 25 loads the linux image.
> > Inserting the values for the variables in this line gives:
> > 'fatload mmc 0:1 0x92000000 image'
> > So we load the kernel image to 0x92000000. Is this not the right adress?
> > How can the right adress, to load the kernel image to, be determined?
> 
> With U-boot, you will have to unfortunately determine the address
manually. I
> usually use the address provided by U-boot for baremetal boot and load
both
> Xen and Linux close to each other.
> 
> > Loading it to 0x80a00000 yields the same error ("Missing kernel boot
> > module?")
> 
> It may be possible that the Device-Tree node is incorrect. Would it be
possible to
> dump the Device-Tree node /chosen/ in either U-boot or Xen?
> 

We tried to load xen, dom0 und fdt close together in an effort to replicate
your approach.
Thats why we now load 
xen     @ 0x8200 0000
dom0    @ 0x8210 0000
fdt     @ 0x8370 0000
To account for these changes, the /chosen node was also adjusted.
/chosen (for readibility as pastebin): 
https://pastebin.com/v6pmm1iq

chosen {
        bootargs = "console=ttyLP3,115200
earlycon=lpuart32,0x5a090000,115200";
        stdout-path = "/serial@5a090000";
        #address-cells = <0x00000002>;
        #size-cells = <0x00000002>;
        module@0 {
                bootargs = "earlycon=xen console=hvc0 loglevel=8
root=/dev/mmcblk0p2 rootwait rw";
                xen,dom0-bootargs = "console=dtuart dtuart=ttyLP3
earlycon=lpuart3,0x5a090000,115200";
                compatible = "xen,linux-zimage", "xen,multiboot-module";
                reg = <0x00000000 0x82100000 0x00000000 0x01490a00>;
        };
};

Regards,

Daniel

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