Re: [Qemu-devel] [RFC QEMU PATCH v3 00/10] Implement vNVDIMM for Xen HVM guest

[Paolo Bonzini <pbonzini@redhat.com>]

On 14/10/2017 00:46, Stefano Stabellini wrote:
> On Fri, 13 Oct 2017, Jan Beulich wrote:
>>>>> On 13.10.17 at 13:13, <haozhong.zhang@intel.com> wrote:
>>> To Jan, Andrew, Stefano and Anthony,
>>>
>>> what do you think about allowing QEMU to build the entire guest ACPI
>>> and letting SeaBIOS to load it? ACPI builder code in hvmloader is
>>> still there and just bypassed in this case.
>> Well, if that can be made work in a non-quirky way and without
>> loss of functionality, I'd probably be fine. I do think, however,
>> that there's a reason this is being handled in hvmloader right now.
> And not to discourage you, just as a clarification, you'll also need to
> consider backward compatibility: unless the tables are identical, I
> imagine we'll have to keep using the old tables for already installed
> virtual machines.

I agree.  Some of them are already identical, some are not but the QEMU
version should be okay, and for yet more it's probably better to keep
the Xen-specific parts in hvmloader.

The good thing is that it's possible to proceed incrementally once you
have the hvmloader support for merging the QEMU and hvmloader RSDT or
XSDT (whatever you are using), starting with just NVDIMM and proceeding
later with whatever you see fit.

Paolo