[multiboot] abstractmbi, modules

[multiboot] abstractmbi, modules

[Grégoire Sutre]

Hi,

I made some tests with the people/phcoder/abstractmbi branch, but I'm a 
bit late reporting them...  Better late than never I guess :-)

I compiled the branch and installed GRUB from Linux on a USB stick, and 
then booted my NetBSD box from the stick, with multiboot.  It worked 
like a charm. :-)

Regarding the question (on irc) whether it also works with modules, it 
turns out that NetBSD/i386 kernel multiboot code lacks module support 
(in -current).  Therefore, to test modules, I tried booting Xen 3.3 
(with NetBSD as DOM0), with:

grub> multiboot (...)/xen.gz console=vga
grub> module (...)/netbsd-XEN3PAE_DOM0 console=pc
grub> boot

and I got an error "Panic on CPU0" from Xen (before booting DOM0).  This 
is with the abstractmbi branch, I didn't try with GRUB trunk.  There are 
some reports in the archives of grub-devel regarding problems with Xen 
3.3, so maybe this is a known issue with GRUB.  Note that with NetBSD's 
boot loader, which is also able to multiboot with modules, doing:

load /netbsd-XEN3PAE_DOM0 console=pc
multiboot /xen.gz console=vga

works fine.

Grégoire

Re: [multiboot] abstractmbi, modules

[Vladimir 'φ-coder/phcoder' Serbinenko]

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Grégoire Sutre wrote:
> Hi,
>
> I made some tests with the people/phcoder/abstractmbi branch, but I'm
> a bit late reporting them...  Better late than never I guess :-)
>
> I compiled the branch and installed GRUB from Linux on a USB stick,
> and then booted my NetBSD box from the stick, with multiboot.  It
> worked like a charm. :-)
>
> Regarding the question (on irc) whether it also works with modules, it
> turns out that NetBSD/i386 kernel multiboot code lacks module support
> (in -current).  Therefore, to test modules, I tried booting Xen 3.3
> (with NetBSD as DOM0), with:
>
> grub> multiboot (...)/xen.gz console=vga
> grub> module (...)/netbsd-XEN3PAE_DOM0 console=pc
> grub> boot
>
> and I got an error "Panic on CPU0" from Xen (before booting DOM0).
It's known problem: xen makes inappropriate assumptions about mbi placement
>   This is with the abstractmbi branch, I didn't try with GRUB trunk. 
> There are some reports in the archives of grub-devel regarding
> problems with Xen 3.3, so maybe this is a known issue with GRUB.  Note
> that with NetBSD's boot loader, which is also able to multiboot with
> modules, doing:
>
> load /netbsd-XEN3PAE_DOM0 console=pc
> multiboot /xen.gz console=vga
>
> works fine.
>
> Grégoire
>
>
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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Re: [multiboot] abstractmbi, modules

[Grégoire Sutre]

Vladimir 'φ-coder/phcoder' Serbinenko wrote:

> It's known problem: xen makes inappropriate assumptions about mbi placement

I'm wondering why it works with the NetBSD boot-loader.  What are these 
assumptions?

Grégoire

Re: [multiboot] abstractmbi, modules

[Robert Millan]

On Thu, Jan 14, 2010 at 08:01:21PM +0100, Grégoire Sutre wrote:
> Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>
>> It's known problem: xen makes inappropriate assumptions about mbi placement
>
> I'm wondering why it works with the NetBSD boot-loader.  What are these  
> assumptions?

Loader in GRUB 2 tends to put MBI and associated structures right after
payload code (unlike GRUB Legacy which uses a fixed location below 1 MiB).

-- 
Robert Millan

  "Be the change you want to see in the world" -- Gandhi

Re: [multiboot] abstractmbi, modules

[Seth Goldberg]

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Hi,

   The latest version of Solaris xVM (based on Xen 3.4) is bootable from GRUB2, 
so that confirms that the bug was fixed in 3.4, so please give that a try.

  --S

Quoting Robert Millan, who wrote the following on Tue, 19 Jan 2010:

> On Thu, Jan 14, 2010 at 08:01:21PM +0100, Grégoire Sutre wrote:
>> Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>>
>>> It's known problem: xen makes inappropriate assumptions about mbi placement
>>
>> I'm wondering why it works with the NetBSD boot-loader.  What are these
>> assumptions?
>
> Loader in GRUB 2 tends to put MBI and associated structures right after
> payload code (unlike GRUB Legacy which uses a fixed location below 1 MiB).
>
> -- 
> Robert Millan
>
>  "Be the change you want to see in the world" -- Gandhi
>
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>

Re: [multiboot] abstractmbi, modules

[Grégoire Sutre]

Seth Goldberg wrote:

>   The latest version of Solaris xVM (based on Xen 3.4) is bootable from 
> GRUB2, so that confirms that the bug was fixed in 3.4, so please give 
> that a try.

Indeed, Xen 3.4.2 (i386) boots fine with GRUB 2.  For the record, the 
command I used is:

grub> multiboot (...)/xen.gz
grub> module (...)/netbsd-XEN3PAE_DOM0.gz /netbsd-XEN3PAE_DOM0.gz console=pc
grub> boot

Thanks,

Grégoire