Re: [Xen-devel] [PATCH RFC 09/12] xen/x86: setup PVHv2 Dom0 ACPI tables

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.07.16 at 18:29, <roger.pau@xxxxxxxxxx> wrote:
> This maps all the regions in the e820 marked as E820_ACPI or E820_NVS to
> Dom0 1:1. It also shadows the page(s) where the native MADT is placed by
> mapping a RAM page over it, copying the original data and modifying it
> afterwards in order to represent the real CPU topology exposed to Dom0.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> FWIW, I think that the current approach that I've used in order to craft the
> MADT is not the best one, IMHO it would be better to place the MADT at the
> end of the E820_ACPI region (expanding it's size one page), and modify the
> XSDT/RSDT in order to point to it, that way we avoid shadowing any other
> ACPI data that might be at the same page as the native MADT (and that needs
> to be modified by Dom0) .

I think I agree. Problem is that you can't be sure there is any space
left after the E820_ACPI region, so I think the placement aspect
would need relaxation.

Jan

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