ACK/Cmnt: [PULL][jammy:linux-aws] aws: Support hibernation on Graviton

[John Cabaj]

On 5/8/24 12:24 PM, Philip Cox wrote:
> SRU Justification:
> 
> BugLink: https://bugs.launchpad.net/bugs/2060992
> 
> [Impact]
> This change contains two parts, the first is adding support for
>   - KVM and guest support for the PSCI SYSTEM_OFF2 (hibernate) call
> 
> And the second part is:
>    - Guest kernel support for clean boot on demand
> 
> For KVM and guest support for the PSCI SYSTEM_OFF2 (hibernate) call:
> 
> PSCI v1.3 adds support for SYSTEM_OFF2 which is analogous to ACPI S4
> state.
> 
> This will allow hosting environments to determine that a guest is
> hibernated rather than just powered off, and ensure that they preserve
> the virtual environment appropriately to allow the guest to resume
> safely (or bump the hardware_signature in the FACS to trigger a clean
> reboot instead).
> 
> For Guest kernel support for clean boot on demand:
> 
> The FACS field in the ACPI table is optional, but can be used
> communicate the hardware_signature field. If this field changes on
> resuming from a hibernation a clean reboot should happen rather than
> the resume from hibernation.
> 
> On hardware reduced platforms[0] this field may exist but it is not
> exposed currently.
> 
> [Fix]
> 
> The changes for KVM and guest support for the PSCI SYSTEM_OFF2
> (hibernate) call come from:
>     
> https://lore.kernel.org/lkml/20240312135958.727765-1-dwmw2@infradead.org
> 
> The changes for Guest kernel support for clean boot on demand come
> from:
>      
> https://lore.kernel.org/lkml/20240312134148.727454-1-dwmw2@infradead.org
> 
> Latest patches have been picked from:
>    - noble/mantic:
> https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/psci-hibernate-6.8
> 
>     - jammy:
> https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/psci-hibernate-5.15
> 
> [Test Plan]
> AWS test.
> 
> [Where problems could occur]
> If on hardware reduced platforms that incorrectly support/advertise the
> FACS field, hibernation may break if it returns a hardware signature
> that changes.
> 
> [Other info]
> SF# 00383181
> 
> [0]: See Section 4.1 of the ACPI spec for info on hardware-reduced
> platforms.
> https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/04_ACPI_Hardware_Specification/ACPI_Hardware_Specification.html
> 
> ----------------------------------------------------------------
> 
> 
> The following changes since commit
> b51d72c21a3c3bb74be5ddc2ef7aeb81a388f3b4:
> 
>   UBUNTU: Ubuntu-aws-5.15.0-1062.68 (2024-04-30 14:50:12 -0400)
> 
> are available in the Git repository at:
> 
>   git+ssh://philcox@git.launchpad.net/~philcox/+git/aws-jammy
> philcox/sf00383181-lp2061006-support-PSCI-SYSTEM_OFF2
> 
> for you to fetch changes up to
> 0244d32caacb1326be8bfe38bd78d3beccaad9d5:
> 
>   UBUNTU: [Config]: Enable hibernate on arm64 (2024-05-08 11:32:53 -
> 0400)
> 
> ----------------------------------------------------------------
> David Woodhouse (6):
>       UBUNTU: SAUCE: PM: hibernate: Allow ACPI hardware signature to be
> honoured
>       UBUNTU: SAUCE: PM: hibernate: Honour ACPI hardware signature by
> default for virtual guests

It looks like this was already committed under https://bugs.launchpad.net/bugs/1965002,
SHA de9f7574b235bf787f9eeb54e5785368895a3b46

>       UBUNTU: SAUCE: ACPICA: Detect FACS even for hardware reduced
> platforms
>       UBUNTU: SAUCE: arm64: acpi: Honour firmware_signature field of
> FACS, if it exists
>       UBUNTU: SAUCE: firmware/psci: Add definitions for PSCI v1.3
> specification (ALPHA)
>       UBUNTU: SAUCE: arm64: Use SYSTEM_OFF2 PSCI call to power off for
> hibernate
> 
> Philip Cox (1):
>       UBUNTU: [Config]: Enable hibernate on arm64
> 

All other cherry-picks applied cleanly. PR merged cleanly.

Acked-by: John Cabaj <john-cabaj at canonical.com>

>  arch/arm64/kernel/acpi.c      | 10 ++++++++++
>  debian.aws/config/annotations | 18 ++++++++++++++++++
>  drivers/acpi/acpica/tbfadt.c  | 30 +++++++++++++-----------------
>  drivers/acpi/acpica/tbutils.c |  7 +------
>  drivers/firmware/psci/psci.c  | 39
> +++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/psci.h     | 27 +++++++++++++++++++++++++++
>  kernel/power/hibernate.c      |  5 ++++-
>  7 files changed, 112 insertions(+), 24 deletions(-)
>