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

[Tim Gardner]

On 5/8/24 11:30 AM, Philip Cox wrote:
> 
> SRU Justification:
> 
> BugLink: https://bugs.launchpad.net/bugs/2060992 
> <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 
> <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 
> <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 <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 <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 <https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/04_ACPI_Hardware_Specification/ACPI_Hardware_Specification.html>
> 
> ----------------------------------------------------------------
> 
> The changes apply cleanly to mantic and noble
> 
> 
> The following changes since commit 9fa50355f6e76412644497bd75e7f958b7d1b640:
> 
> UBUNTU: Ubuntu-aws-6.8.0-1003.3 (2024-04-10 18:05:01 +0200)
> 
> are available in the Git repository at:
> 
> git+ssh://philcox@git.launchpad.net/~philcox/+git/aws-noble 
> philcox/sf00383181-lp2061006-support-PSCI-SYSTEM_OFF2
> 
> for you to fetch changes up to 3dfe0bdca8a4b1556a62e4e27ff1f27b3fd123a7:
> 
> UBUNTU: [Config]: Enable hibernate on arm64 (2024-05-08 12:42:40 -0400)
> 
> ----------------------------------------------------------------
> David Woodhouse (8):
> UBUNTU: SAUCE: firmware/psci: Add definitions for PSCI v1.3 
> specification (ALPHA)
> UBUNTU: SAUCE: KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for 
> hibernation
> UBUNTU: SAUCE: KVM: arm64: Add support for PSCI v1.2 and v1.3
> UBUNTU: SAUCE: KVM: selftests: Add test for PSCI SYSTEM_OFF2
> UBUNTU: SAUCE: KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
> UBUNTU: SAUCE: arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate
> UBUNTU: SAUCE: ACPICA: Detect FACS even for hardware reduced platforms
> UBUNTU: SAUCE: arm64: acpi: Honour firmware_signature field of FACS, if 
> it exists
> 
> Philip Cox (1):
> UBUNTU: [Config]: Enable hibernate on arm64
> 
> Documentation/virt/kvm/api.rst | 11 +++++
> arch/arm64/include/uapi/asm/kvm.h | 6 +++
> arch/arm64/kernel/acpi.c | 10 ++++
> arch/arm64/kvm/hyp/nvhe/psci-relay.c | 2 +
> arch/arm64/kvm/hypercalls.c | 2 +
> arch/arm64/kvm/psci.c | 43 ++++++++++++++++-
> debian.aws/config/annotations | 15 ++++++
> drivers/acpi/acpica/tbfadt.c | 30 ++++++------
> drivers/acpi/acpica/tbutils.c | 7 +--
> drivers/firmware/psci/psci.c | 37 +++++++++++++++
> include/kvm/arm_psci.h | 4 +-
> include/uapi/linux/psci.h | 20 ++++++++
> kernel/power/hibernate.c | 5 +-
> tools/testing/selftests/kvm/aarch64/psci_test.c | 61 
> +++++++++++++++++++++++++
> 14 files changed, 227 insertions(+), 26 deletions(-)
> 
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>

"UBUNTU: [Config]: Enable hibernate on arm64" did not apply to 
Mantic/linux-aws, but you can figure that one out.
-- 
-----------
Tim Gardner
Canonical, Inc