about mini-os

about mini-os

[余上]

Hi all ,

I find that it needs some hacks to run mini-os under xen-3.2 ,
followings are what I have done:

1, mini-os/arch/x86/x86_32.S , change the __xen_guest config :
from
        .ascii  ",VIRT_BASE=0x0" /* &_text from minios_x86_32.lds */
        .ascii  ",ELF_PADDR_OFFSET=0x0"
to
	.ascii	",VIRT_BASE=0x0C0000000" /* &_text from minios_x86_32.lds */
	.ascii	",ELF_PADDR_OFFSET=0x0C0000000"
because if I don't change VIRT_BASE xen will report "Initial loading
isn't allowed to lowest 1GB of memory"

2, mini-os/arch/x86/minios-x86_32.lds
from
  . = 0x0;
to
  . = 0x0C0000000;

so far , I can run mini-os to the banner and got a page fault:
Bootstraping ...
Xen Minimal OS!
Page fault at linear address 15555c08, eip c000cf61, code 0
(XEN) Domain 0 crashed

any idea ? Thank you very much
yushang

Re: about mini-os

[Samuel Thibault]

Hello,

余上, le Tue 22 Jan 2008 17:23:18 +0800, a écrit :
> 	.ascii	",VIRT_BASE=0x0C0000000" /* &_text from minios_x86_32.lds */
> 	.ascii	",ELF_PADDR_OFFSET=0x0C0000000"
> because if I don't change VIRT_BASE xen will report "Initial loading
> isn't allowed to lowest 1GB of memory"

Oh, you seem to be starting mini-os as Domain-0...  Is that supposed to
be supported?

> so far , I can run mini-os to the banner and got a page fault:
> Bootstraping ...
> Xen Minimal OS!
> Page fault at linear address 15555c08, eip c000cf61, code 0
> (XEN) Domain 0 crashed
> 
> any idea ? Thank you very much

Mmm, this is Xen-unstable, not Xen-3.2, isn't it?  Well, yes, the code I
got added was supposing _text to be 0, I've submitted a fix for that.

Samuel

Re: about mini-os

[余上]

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You mean I can't run mini-os in dom0 ? But for learning purpose I
really want to . Maybe I need some more hacks ? By the way , I'm using
xen-3.2 (Xen 3.2 official source distribution tarball)

2008/1/22, Samuel Thibault <samuel.thibault@eu.citrix.com>:
> Hello,
>
> 余上, le Tue 22 Jan 2008 17:23:18 +0800, a écrit :
> >       .ascii  ",VIRT_BASE=0x0C0000000" /* &_text from minios_x86_32.lds */
> >       .ascii  ",ELF_PADDR_OFFSET=0x0C0000000"
> > because if I don't change VIRT_BASE xen will report "Initial loading
> > isn't allowed to lowest 1GB of memory"
>
> Oh, you seem to be starting mini-os as Domain-0...  Is that supposed to
> be supported?
>
> > so far , I can run mini-os to the banner and got a page fault:
> > Bootstraping ...
> > Xen Minimal OS!
> > Page fault at linear address 15555c08, eip c000cf61, code 0
> > (XEN) Domain 0 crashed
> >
> > any idea ? Thank you very much
>
> Mmm, this is Xen-unstable, not Xen-3.2, isn't it?  Well, yes, the code I
> got added was supposing _text to be 0, I've submitted a fix for that.
>
> Samuel
>

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Re: about mini-os

[Samuel Thibault]

余上, le Tue 22 Jan 2008 20:16:54 +0800, a écrit :
> You mean I can't run mini-os in dom0 ?
> But for learning purpose I really want to .

Well, I don't really see the use. mini-os completely relies on backends
and is unable to drive any real hardware.  Why not running e.g. a Linux
as dom0 and then run mini-os as domU?  That makes a much faster testing
environment.

> Maybe I need some more hacks ?

Well, the hack you propose is indeed necessary, but I doubt it should
really make it in upstream

Samuel