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

[Boris Ostrovsky]

On 11/03/2017 02:40 PM, Juergen Gross wrote:
> On 03/11/17 19:35, Boris Ostrovsky wrote:
>> On 11/03/2017 02:23 PM, Juergen Gross wrote:
>>> On 03/11/17 19:19, Boris Ostrovsky wrote:
>>>> On 11/03/2017 02:05 PM, Juergen Gross wrote:
>>>>> So again the question: how to tell whether we are PVH or HVM in
>>>>> init_hypervisor_platform()? ACPi tables are scanned way later...
>>>> Can we make grub/OVMF append a boot option?
>>>>
>>>> Or set setup_header.hardware_subarch to something? We already have
>>>> X86_SUBARCH_XEN but it is only used by PV.  Or we might be able to use
>>>> hardware_subarch_data (will need to get a buy-in from x86 maintainers, I
>>>> think).
>>> But wouldn't this break the idea to reuse the native boot paths in
>>> grub/OVMF without further modifications?
>> WDYM? We will have to have some sort of a plugin in either one to build
>> the zeropage anyway. So we'd set hardware_subarch there, in addition to
>> other things like setting memory and such.
> But isn't the zeropage already being built? I admit that setting subarch
> isn't a big deal, but using another entry with a passed-through pvh
> start struct isn't either...

I don't follow, sorry. My understanding is that zeropage will be built
by PVH-enlightened grub so part of this process would be setting the
subarch bit.

-boris