Re: [PATCH v2] hvmloader: flip "ACPI data" to "ACPI NVS" type for ACPI table region

[Jan Beulich <jbeulich@xxxxxxxx>]

On 16.10.2020 02:39, Igor Druzhinin wrote:
> ACPI specification contains statements describing memory marked with regular
> "ACPI data" type as reclaimable by the guest. Although the guest shouldn't
> really do it if it wants kexec or similar functionality to work, there
> could still be ambiguities in treating these regions as potentially regular
> RAM.
> 
> One such example is SeaBIOS which currently reports "ACPI data" regions as
> RAM to the guest in its e801 call. Which it might have the right to do as any
> user of this is expected to be ACPI unaware. But a QEMU bootloader later seems
> to ignore that fact and is instead using e801 to find a place for initrd which
> causes the tables to be erased. While arguably QEMU bootloader or SeaBIOS need
> to be fixed / improved here, that is just one example of the potential 
> problems
> from using a reclaimable memory type.
> 
> Flip the type to "ACPI NVS" which doesn't have this ambiguity in it and is
> described by the spec as non-reclaimable (so cannot ever be treated like RAM).
> 
> Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>