Re: [Xen-devel] Bare-metal Xen on ARM boot

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Sun, 2013-04-28 at 15:04 +0100, Stefano Stabellini wrote:
> On Fri, 26 Apr 2013, Sander Bogaert wrote:
> > >> I was getting the number from xen/arch/arm/traps.c:706 ''call =
> > >> arm_hypercall_table[regs->r12].fn;" and the arm_hypercall_table in the
> > >> same file. It should have been #4 by that reasoning I know.
> > >
> > > That macro is such that the fact that something appears at position N In
> > > the list doesn't mean it is position N in the resulting array, it
> > > expands into the syntax
> > > array[] = {
> > >         [1] = a_thing
> > >         [4] = another_thing
> > > }
> > > which initialises slots 1 and 4.
> > 
> > Thanks, I overlooked that.
> > 
> > >>
> > >> Also, I was trying an ELF file. I will try again tomorrow with a
> > >> zImage header and report back.
> > >>
> > >> Thanks,
> > >> Sander
> > >
> > >
> > 
> > ELF does seem to be supported but then it gets stuck further down in
> > domain builder code ( I also attached the entire output) :
> > 
> > domainbuilder: detail: xc_dom_parse_elf_kernel: xen-3.0-unknown:
> > 0x80000000 -> 0x80010010
> > xc: error: panic: xc_dom_core.c:608: xc_dom_find_arch_hooks: not found
> > (type xen-3.0-unknown): Invalid kernel
> > xc: error: panic: xc_dom_core.c:763: xc_dom_mem_init: arch hooks not
> > set: Internal error
> > libxl: error: libxl_dom.c:384:libxl__build_pv: xc_dom_mem_init failed:
> > No such file or directory
> > 
> > The vmlinux binary ( elf ) doesn't boot neither and has the same
> > problem. Could it have something to do with:
> > "xc: detail: elf_xen_note_check: Not bothering with notes on ARM"
> > Missing metadata?
> > 
> > I'll focus on getting an zImage working.
> 
> The problem seems to be that dom->guest_type is set to
> "xen-3.0-unknown" by xc_dom_guest_type at the end of
> xc_dom_parse_elf_kernel.
> In order to match the ARMv7 supported guest_type it should have been
> "xen-3.0-armv7l", as you can see from
> xc_dom_armzimageloader.c:xc_dom_parse_zimage_kernel.
> 
> Maybe we just need to add the appropriate case in the switch in
> xc_dom_guest_type (see below)?

We certainly need to add something there, and your string seems as
plausible as the next one ;-)

I suppose we need to handle EM_AARCH64 at some point too...

I reckon a warning print under the default case would have us then and
other porters in the future...

> 
> diff --git a/tools/libxc/xc_dom_elfloader.c b/tools/libxc/xc_dom_elfloader.c
> index 6583859..911f316 100644
> --- a/tools/libxc/xc_dom_elfloader.c
> +++ b/tools/libxc/xc_dom_elfloader.c
> @@ -74,6 +74,8 @@ static char *xc_dom_guest_type(struct xc_dom_image *dom,
>          }
>      case EM_X86_64:
>          return "xen-3.0-x86_64";
> +    case EM_ARM:
> +        return "xen-3.0-armv7l";
>      default:
>          return "xen-3.0-unknown";
>      }



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