[PATCH v14 0/4] Enable guest suspend/resume support on ARM via vPSCI

[Mykola Kvach <xakep.amatop@gmail.com>]

This patch series introduces the initial support for guest suspend
and resume on ARM platforms using the PSCI SYSTEM_SUSPEND interface. The main
goal is to allow ARM guests to request suspension using PSCI and be resumed
by the control domain (e.g., via "xl resume").


Background

The PSCI SYSTEM_SUSPEND call is part of the PSCI v1.0+ specification and is
used by guests to enter the deepest possible power state. On Xen/ARM, we
emulate this interface in the virtual PSCI (vPSCI) layer for guests.

This series includes:

1. A new vPSCI implementation of the PSCI SYSTEM_SUSPEND function for guests
2. Documentation updates to SUPPORT.md to reflect PSCI and vPSCI support status
3. Enabling "xl resume" command compilation for ARM, which was previously disabled


Usage

For Linux-based guests:
  - Suspend can be triggered using: "echo mem > /sys/power/state" or "systemctl suspend"
  - Resume can be performed from control domain using: "xl resume <domain>"

For more information, refer to the official Linux kernel documentation on power management.

Note that currently, SYSTEM_SUSPEND is supported only for guest domains (not for
the hardware domain).
---

This is the first part of previous patch series and originally consist only
with necessary changes needed for guest domain suspend.

The second part can be found here:
    https://patchew.org/Xen/cover.1756763487.git.mykola._5Fkvach@epam.com/
---

Changes introduced in v14:
- move arch_domain_resume() to its own header, drop typeof usage for
  the resume context, move resume error prints into arch_domain_resume(),
  and address review nits
- move the suspend-to-RAM changelog entry to the 4.22 section
- commit message tweaks.

Mykola Kvach (4):
  xen/arm: Implement PSCI SYSTEM_SUSPEND call for guests
  tools/xl: Allow compilation of 'xl resume' command on Arm
  SUPPORT.md: Document PSCI SYSTEM_SUSPEND support for guests
  CHANGELOG: Document guest suspend/resume to RAM support on Arm

 CHANGELOG.md                          |   4 +
 SUPPORT.md                            |   5 +-
 tools/include/libxl.h                 |   1 -
 tools/xl/xl.h                         |   4 +-
 tools/xl/xl_cmdtable.c                |   4 +-
 tools/xl/xl_migrate.c                 |   2 +-
 tools/xl/xl_saverestore.c             |   2 +-
 tools/xl/xl_vmcontrol.c               |  12 +--
 xen/arch/arm/domain.c                 |  41 +++++++++
 xen/arch/arm/include/asm/domain.h     |   2 +
 xen/arch/arm/include/asm/perfc_defn.h |   1 +
 xen/arch/arm/include/asm/psci.h       |   2 +
 xen/arch/arm/include/asm/suspend.h    |  24 ++++++
 xen/arch/arm/include/asm/vpsci.h      |   5 +-
 xen/arch/arm/vpsci.c                  | 116 +++++++++++++++++++++-----
 xen/common/domain.c                   |   5 ++
 xen/include/xen/suspend.h             |  15 ++++
 17 files changed, 208 insertions(+), 37 deletions(-)
 create mode 100644 xen/arch/arm/include/asm/suspend.h
 create mode 100644 xen/include/xen/suspend.h

-- 
2.43.0