Question about paravirt_ops (hardware_subarch in boot.txt)

Question about paravirt_ops (hardware_subarch in boot.txt)

[Atsushi SAKAI]

Hi,

I have a question about paravirt_ops switch on Xen tool side.
According to boot.txt 2.07(for example linux-2.6.28/Documentations/x86/boot.txt)
"hardware_subarch" sets the boot hypervisor.
(for lguest and Xen)

but Xen code does not have the code which write the "hardware_subarch"

In my survey, the patch which writes value "hardware_subarch" is already posted.
http://lists.xensource.com/archives/html/xen-devel/2007-06/msg00619.html
But It does not included xen-unstable at this moment.

Would you point the installation procedure on Xen side?

or paravirt_ops(x86) for Xen supports another method to boot?
(like option rom for vmi)

Thanks
Atsushi SAKAI

Re: Question about paravirt_ops (hardware_subarch in boot.txt)

[Jeremy Fitzhardinge]

Atsushi SAKAI wrote:
> Hi,
>
> I have a question about paravirt_ops switch on Xen tool side.
> According to boot.txt 2.07(for example linux-2.6.28/Documentations/x86/boot.txt)
> "hardware_subarch" sets the boot hypervisor.
> (for lguest and Xen)
>
> but Xen code does not have the code which write the "hardware_subarch"
>
> In my survey, the patch which writes value "hardware_subarch" is already posted.
> http://lists.xensource.com/archives/html/xen-devel/2007-06/msg00619.html
> But It does not included xen-unstable at this moment.
>
> Would you point the installation procedure on Xen side?
>
> or paravirt_ops(x86) for Xen supports another method to boot?
> (like option rom for vmi)

Xen does not use the subarch mechanism to boot.  The bzImage file 
contains a complete ELF file of the kernel, which includes ELF notes in 
its notes section.  One of these notes contains the entry address for 
the kernel, which points to the first instruction of the Xen-specific 
boot path.

Install details are inherently distro-dependent, but current versions of 
Redhat and Fedora will happily do a full PV install if you start their 
standard install kernel+initrd image under Xen.

If you use pygrub, you can use the same grub config file to boot the 
same kernel either native or under Xen.

    J