Re: [Xen-devel] boot-wrapped xen image barfs with overlapped sections

[Jun Sun <jsun@xxxxxxxxxx>]

I finally resolved this issue after hunting around.  The clue comes from this page, https://wiki.linaro.org/LEG/Engineering/Virtualization/Xen_ARM_Guide:

/chosen/module@1/reg should match bootwrapper model.lds.

Basically if I increase memory region for kernel, I should also update dts file on  /chosen/module@1/reg.

Here is what in model.xen.lds.  As you can see, kernel area is increased to 14MB.  

OUTPUT_FORMAT("elf64-littleaarch64")

OUTPUT_ARCH(aarch64)

TARGET(binary)

INPUT(./boot.xen.o)

INPUT(Xen)

INPUT(Image)

INPUT(./fdt.dtb)

SECTIONS

{

 . = 0x80000000;

 .text : { boot.xen.o }

 . = 0x80000000 + 0xfff8;

 mbox = .;

 .mbox : { QUAD(0x0) }

 . = 0x80000000 + 0xE00000;

 xen = .;

 .xen : { Xen }

 . = 0x80000000 + 0x80000;

 kernel = .;

 .kernel : { Image }

 . = 0x80000000 + 0x08000000;

 dtb = .;

 .dtb : { ./fdt.dtb }

 .data : { *(.data) }

 .bss : { *(.bss) }

}

And here is what in foundation-v8.dts for chosen:

        chosen {

                #address-cells = <0x1>;

                #size-cells = <0x1>;

                xen,xen-bootargs = "dom0_mem=512M dom0_max_vcpus=2 dtuart=serial0 conswitch=x loglvl=all guest_loglvl=all no-bootscrub";

                module@1 {

                        compatible = "xen,linux-zimage", "xen,multiboot-module";

                        reg = <0x80080000 0xe00000>;

                        bootargs = "earlyprintk=pl011,0x1c090000 console=hvc0 root=/dev/vda2 debug rw";

                };

        };

Kernels can be any recent 4.x kernel from torvalds, stable or linaro trees.

Now move to on to boot kernel with initrd.

Jun

On Fri, Sep 16, 2016 at 2:44 PM, Jun Sun <jsun@xxxxxxxxxx> wrote:

Hi, all,

I have been following the instructions at https://wiki.linaro.org/LEG/Engineering/Virtualization/Xen_on_ARMv8_Foundation to build xen for arm64.

When I tried to use the latest kernel instead of v3.13 as suggested, I failed when building boot-wrapped image.  See below.

=======================

jsun@ubuntu:~/work/xen/linaro-2014-guide/boot-wrapper-aarch64$ make CROSS_COMPILE=aarch64-linux-gnu- FDT_SRC=foundation-v8.dts xen-system.axf

aarch64-linux-gnu-ld -o xen-system.axf --script=model.xen.lds

aarch64-linux-gnu-ld: section .xen loaded at [0000000080a00000,0000000080ac061f] overlaps section .kernel loaded at [0000000080080000,0000000080c50dff]

Makefile:78: recipe for target 'xen-system.axf' failed

make: *** [xen-system.axf] Error 1

=======================

Obviously the issue is that linker script gives about 8.5MB space for kernel which is too small. If I modify the linker script to give more space to kernel, the xen will halt during boot up right before Dom0 starts:

==========================

(XEN) *** LOADING DOMAIN 0 ***

(XEN) Loading kernel from boot module @ 0000000080080000

(XEN) Allocating 1:1 mappings totalling 512MB for dom0:

(XEN) BANK[0] 0x000000a0000000-0x000000c0000000 (512MB)

(XEN) Grant table range: 0x000000ffe00000-0x000000ffe5e000

(XEN) Loading zImage from 0000000080080000 to 00000000a0080000-00000000a0880000

(XEN) Allocating PPI 16 for event channel interrupt

(XEN) Loading dom0 DTB to 0x00000000a8000000-0x00000000a8000fe7

(XEN) Std. Loglevel: All

(XEN) Guest Loglevel: All

(XEN) *** Serial input -> DOM0 (type 'CTRL-x' three times to switch input to Xen)

(XEN) Freed 276kB init memory.

==========================

Any pointers on the right way to get modern kernel working with xen on ARM64?

Thanks.

Jun

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