Re: [PATCH 00/13] microvm: add acpi support

[Paolo Bonzini]

On 19/03/20 09:01, Gerd Hoffmann wrote:
> I know that not supporting ACPI in microvm is intentional.  If you still
> don't want ACPI this is perfectly fine, you can use the usual -no-acpi
> switch to toggle ACPI support.

Could we change -no-acpi into a "-machine acpi=..." property?  Then it
can have type OnOffAuto and we can decide whether to enable it by
default or not for microvm.

Also, can you confirm that it builds without CONFIG_I440FX and
CONFIG_Q35?  You probably need to add "imply ACPI" and possibly some
'#include "config-devices.h"' and '#ifdef CONFIG_ACPI' here and there.

Paolo

> These are the advantages you are going to loose then:
> 
>   (1) virtio-mmio device discovery without command line hacks (tweaking
>       the command line is a problem when not using direct kernel boot).
>   (2) Better IO-APIC support, we can use IRQ lines 16-23.
>   (3) ACPI power button (aka powerdown request) works.
>   (4) machine poweroff (aka S5 state) works.
> 
> Together with seabios patches for virtio-mmio support this allows to
> boot standard fedora images (cloud, coreos, workstation live) with the
> microvm machine type.