[PULL][SRU Xenial] Support QEMU guests in ACPI mode

[Kleber Souza]

On 02/27/18 22:12, dann frazier wrote:
> Thanks Kleber,
>   Can you elaborate on your concern regarding this option on other
> architectures?
> I know that work is going on upstream to enable this code for x86:
>   https://lkml.org/lkml/2018/1/18/440
> 
> If we grow those patches, wouldn't we want to parse the SPCR table on
> platforms that provide it?

On a second thought and looking better at where upstream is heading, if
we ever backport the patch you mentioned to enable the code for x86,
there won't be any reason not to enable the config option as well, and
having an annotation entry doesn't seem to bring much benefit in that case.

So the pull request looks good to me, I'll send my ACK.


Thanks!
Kleber

> 
>   -dann
> 
> On Mon, Feb 26, 2018 at 11:12 AM, Kleber Souza
> <kleber.souza at canonical.com> wrote:
>> Hi Dann,
>>
>> Regarding patch 9/11 there's a comment on the bug:
>>
>> "Patch 9 turns on CONFIG_ACPI_SPCR_TABLE - however, this driver will
>> only be built for arm64. TBH, I'm not 100% sure how Kconfig knows not to
>> build this for other archs - but I checked the logs, and there's no
>> spcr.o built on other archs. (Not that that should be a problem - they
>> would just grow a bit of unused code)."
>>
>> Indeed the CONFIG_ACPI_SPCR_TABLE is not set for arches other than
>> arm64, that's because the config option is added as non-visible and it's
>> only selected by arch/arm64/Kconfig. But I'm a bit concerned about the
>> possibility of an accidental enablement of this config option for
>> another arch in the future.
>>
>> To solve this problem, my suggestion would be to set the default of the
>> config option to 'n' on drivers/acpi/Kconfig and set it to =y only on
>> debian.master/config/arm64/config.common.arm64 (this would be done
>> automatically by 'updateconfigs'). It's probably a good idea to add an
>> entry on the annotations file as well.
>>
>>
>> Thanks,
>> Kleber
>>
>>
>> On 02/02/18 00:00, dann frazier wrote:
>>> BugLink: https://bugs.launchpad.net/bugs/1744754
>>>
>>> qemu-efi, the UEFI firmware used to boot arm64 KVM guests, has
>>> switched from devicetree to ACPI by default. However, the GA xenial
>>> kernel didn't have enough ACPI support to boot in this mode. That
>>> means, for example, that your bionic-based OpenStack won't be able to
>>> boot xenial cloud images. This series backports the minimum necessary
>>> ACPI support back to 4.4: GICv3 and SPCR console detection.
>>>
>>> The testing/risk assessment is all there in the bug, as is a
>>> discussion of other possible solutions. The GICv3 support comprises
>>> all clean cherry-picks. Some backporting was required for the console
>>> stuff - I've annotated each patch with the details in each patch above
>>> my S-o-b.
>>>
>>> Test builds are available in ppa:dannf/test.
>>>
>>> The following changes since commit 355335ee775c4016a34b22e99e14cf5bc9534c1b:
>>>
>>>   UBUNTU: [Packaging] update urgency to medium by default (2018-01-29
>>> 13:09:24 +0100)
>>>
>>> are available in the Git repository at:
>>>
>>>   git://git.launchpad.net/~dannf/ubuntu/+source/linux/+git/linux minacpi-x
>>>
>>> for you to fetch changes up to eb0e0630ae2860f70f017a1b11ee356d736edf9e:
>>>
>>>   serial: pl011: add console matching function (2018-01-31 16:12:16 -0700)
>>>
>>> ----------------------------------------------------------------
>>> Aleksey Makarov (4):
>>>       ACPICA: Headers: Add new constants for the DBG2 ACPI table
>>>       ACPI: parse SPCR and enable matching console
>>>       ARM64: ACPI: enable ACPI_SPCR_TABLE
>>>       serial: pl011: add console matching function
>>>
>>> Hanjun Guo (1):
>>>       irqchip/gic-v3: Remove gic_root_node variable from the ITS code
>>>
>>> Leif Lindholm (1):
>>>       of/serial: move earlycon early_param handling to serial
>>>
>>> Tomasz Nowicki (4):
>>>       irqchip/gic-v3: Refactor gic_of_init() for GICv3 driver
>>>       irqchip/gic-v3: Add ACPI support for GICv3/4 initialization
>>>       irqchip/gic-v3: ACPI: Add redistributor support via GICC structures
>>>       irqchip/gic-v3-its: Mark its_init() and its children as __init
>>>
>>> dann frazier (1):
>>>       UBUNTU: [Config] CONFIG_ACPI_SPCR_TABLE=y
>>>
>>>  arch/arm64/Kconfig                        |   1 +
>>>  arch/arm64/kernel/acpi.c                  |  11 +-
>>>  debian.master/config/config.common.ubuntu |   1 +
>>>  drivers/acpi/Kconfig                      |   3 +
>>>  drivers/acpi/Makefile                     |   1 +
>>>  drivers/acpi/spcr.c                       | 111 ++++++++++
>>>  drivers/irqchip/irq-gic-v3-its.c          |  10 +-
>>>  drivers/irqchip/irq-gic-v3.c              | 347 +++++++++++++++++++++++++-----
>>>  drivers/of/fdt.c                          |  11 +-
>>>  drivers/tty/serial/amba-pl011.c           |  55 +++++
>>>  drivers/tty/serial/earlycon.c             |  20 +-
>>>  include/acpi/actbl2.h                     |   7 +-
>>>  include/linux/acpi.h                      |   6 +
>>>  include/linux/of_fdt.h                    |   3 +
>>>  include/linux/serial_core.h               |   9 +-
>>>  15 files changed, 527 insertions(+), 69 deletions(-)
>>>  create mode 100644 drivers/acpi/spcr.c
>>>