Re: [PATCH v2 00/13] microvm: add acpi support

[Philippe Mathieu-Daudé]

On 5/5/20 4:04 PM, Michael S. Tsirkin wrote:
> On Tue, May 05, 2020 at 03:42:52PM +0200, 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.
> >
> > 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.
>
> Questions
>
> - what's the tradeoff in startup time?
> - what should be the default?
>
> Based on above I'd be inclined to say default should stay no acpi and
> users should enable acpi with an option.

As this machine was added to have the least minimum hardware required, 
I'd keep the default with no ACPI and have user requiring it to use an 
option. My 2 cents obviously.

> > Together with seabios patches for virtio-mmio support this allows to
> > boot standard fedora images (cloud, coreos, workstation live) with the
> > microvm machine type.
> >
> > git branch for testing (including updated seabios):
> >         https://git.kraxel.org/cgit/qemu/log/?h=sirius/microvm
> >
> > changes in v2:
> >    * some acpi cleanups are an separate patch series now.
> >    * switched to hw reduced acpi & generic event device.
> >    * misc fixes here and there.
> >
> > cheers,
> >    Gerd
> >
> > Gerd Hoffmann (13):
> >    acpi: make build_madt() more generic.
> >    acpi: create acpi-common.c and move madt code
> >    acpi: madt: skip pci override on pci-less systems (microvm)
> >    acpi: move acpi_build_facs to acpi-common.c
> >    acpi: move acpi_init_common_fadt_data to acpi-common.c
> >    acpi: move acpi_align_size to acpi-common.h
> >    acpi: fadt: add hw-reduced sleep register support
> >    acpi: generic event device for x86
> >    microvm: add minimal acpi support
> >    microvm: disable virtio-mmio cmdline hack
> >    microvm: add acpi_dsdt_add_virtio() for x86
> >    microvm: make virtio irq base runtime configurable
> >    microvm/acpi: use GSI 16-23 for virtio
> >
> >   hw/i386/acpi-common.h                  |  38 ++++
> >   hw/i386/acpi-microvm.h                 |   6 +
> >   include/hw/acpi/acpi-defs.h            |   2 +
> >   include/hw/acpi/generic_event_device.h |  10 +
> >   include/hw/i386/microvm.h              |  10 +-
> >   hw/acpi/aml-build.c                    |   4 +-
> >   hw/i386/acpi-build.c                   | 198 +-------------------
> >   hw/i386/acpi-common.c                  | 206 ++++++++++++++++++++
> >   hw/i386/acpi-microvm.c                 | 249 +++++++++++++++++++++++++
> >   hw/i386/generic_event_device_x86.c     | 114 +++++++++++
> >   hw/i386/microvm.c                      |  36 +++-
> >   hw/i386/Kconfig                        |   1 +
> >   hw/i386/Makefile.objs                  |   3 +
> >   13 files changed, 676 insertions(+), 201 deletions(-)
> >   create mode 100644 hw/i386/acpi-common.h
> >   create mode 100644 hw/i386/acpi-microvm.h
> >   create mode 100644 hw/i386/acpi-common.c
> >   create mode 100644 hw/i386/acpi-microvm.c
> >   create mode 100644 hw/i386/generic_event_device_x86.c
> >
> > --
> > 2.18.4