Re: [Xen-devel] Xen PVH support in grub2

[Juergen Gross]

On 29/09/17 17:51, Roger Pau Monné wrote:
> On Fri, Sep 29, 2017 at 03:33:58PM +0000, Juergen Gross wrote:
>> On 29/09/17 17:24, Roger Pau Monné wrote:
>>> On Fri, Sep 29, 2017 at 02:46:53PM +0000, Juergen Gross wrote:
>>> Then, I also wonder whether it would make sense for this grub to load
>>> the kernel using the PVH entry point or the native entry point. Would
>>> it be possible to boot a Linux kernel up to the point where cpuid can
>>> be used inside of a PVH container?
>>
>> I don't think today's Linux allows that. This has been discussed
>> very thoroughly at the time Boris added PVH V2 support to the kernel.
> 
> OK, I'm not going to insist on that, but my plans for FreeBSD is to
> make the native entry point capable of booting inside of a PVH
> container up to the point where cpuid (or whatever method) can be used
> to detect the environment.

Looking more thoroughly into the Linux boot code I think this could
work for Linux, too. But only if we can tell PVH from HVM in the guest.
How would you do that in FreeBSD? Via flags in the boot params? This
would the have to be done in the boot loader (e.g. grub or OVMF).


Juergen