Re: pvhgrub docs

[Andy Smith <andy@xxxxxxxxxxxxxx>]

Hello,

On Thu, Oct 07, 2021 at 02:47:08PM -0700, David Hill wrote:
> pvhgrub is new to me, but to understand the transition away from pygrub, I
> found pvgrub2 documentation helpful (although some of it is a bit dated):
> 
> https://wiki.xenproject.org/wiki/PvGrub2

Ah yes, that's another one I used to get the idea of the basic
concept, and if you still need to run PV domains that would be the
way to do it still.

But if the guest kernel is new enough I recommend just go straight
to PVH mode now, which for this style of booting does need grub
compiled as --with-platform=xenpvh

On Debian dom0 if you install grub-xen-host you get pvgrub images
at:

    /usr/lib/grub-xen/grub-x86_64-xen.bin
    /usr/lib/grub-xen/grub-i386-xen.bin

and pvhgrub image at:

    /usr/lib/grub-xen/grub-i386-xen_pvh.bin

The PVH one should work for both 64- and 32-bit.

If needing the specific one for 32-bit PV then bear in mind that:

- there's no security support from Xen for that

- 32-bit PV guest support is removed in 4.15

- support for booting as 32-bit PV guest was already removed in
  Linux kernel at v5.9.

Cheers,
Andy