This series fully models the behaviour of WFxT instructions. We
already had support for WFE for M-profile but we left off A-profile as
it has more potential sources of wake-ups. The main one is the event
stream which includes events from significant bits of the timer
ticking over.

The refactoring from the previous iterations of the patch have now
been merged.

I've dropped trying to fully model the global monitor in favour of
taking advantage of the architectural flexibility to have an IMPDEF
event wake up for any reason. We treat the setting of exclusive_addr
as such a reason because it indicates the current vCPU is in a ldstx
exclusive region and we don't want the guest to deadlock. This does mean
the system won't sleep on WFE enabled locks but people shouldn't be
relying on QEMU to model real world sleep patterns anyway given the
efficiency of emulation compared to real HW.

I've written a test case using kvm-unit-tests:

  Message-ID: <20260527111822.1563679-1-alex.bennee@linaro.org>
  Date: Wed, 27 May 2026 12:18:21 +0100
  Subject: [kvm-unit-tests PATCH v2] arm: add wfx test case
  From: =?UTF-8?q?Alex=20Benn=C3=A9e?= <alex.bennee@linaro.org>

v8
  - Fixed quanta-gsj model SEV errata failure
  - Update the aspeed_anacapa test case
  - Ensure wake up events for V6K/V7 and plain V8
  - merged trap with implementation

v7
  - more r-b's
  - extended comment for typo fix
v6
  - add typo fix
  - addressed rth's comments

v5
  - addressed rth's comments
  - all but one patch now reviewed

v4
  - precursor refactor patches now merged
  - dropped global monitor emulation
  - addressed other comments
  - tested with check-tcg and kvm-unit-test wfx tests

v3
  - fixed the WFE exception handling

v2
  - I've kept the tests separate, see:

    Message-ID: <20260417164328.1009132-1-alex.bennee@linaro.org>
    Date: Fri, 17 Apr 2026 17:43:20 +0100
    Subject: [PATCH 0/7] tests/tcg: more capabilities for aarch64-softmmu tests
    From: =?UTF-8?q?Alex=20Benn=C3=A9e?= <alex.bennee@linaro.org>

  - tweaks to global monitor behaviour
  - STLR/STL will also trigger events to avoid deadlocks
  - see under the --- in the patches for details

Alex.

Alex Bennée (7):
  hw/arm: use cortex-a9 mpcore base for CBAR on npcm7xx machines
  tests/functional: update anacapa-bmc image
  target/arm: do not clear halting reason in has_work helper
  target/arm: ensure we create the wxft_timer for all modes
  target/arm: implements SEV/SEVL for all modes
  target/arm: enable WFE sleeping for A-profile
  target/arm: implement WFET

 include/hw/core/sysemu-cpu-ops.h            |   3 +
 target/arm/cpu.h                            |   2 +-
 target/arm/tcg/helper-defs.h                |   3 +-
 target/arm/tcg/translate.h                  |  18 ++
 target/arm/tcg/a32.decode                   |   5 +-
 target/arm/tcg/a64.decode                   |   5 +-
 target/arm/tcg/t16.decode                   |   4 +-
 target/arm/tcg/t32.decode                   |   4 +-
 hw/arm/npcm7xx.c                            |   2 +-
 target/arm/cpu.c                            |  26 +-
 target/arm/tcg/op_helper.c                  | 252 ++++++++++++++++++--
 target/arm/tcg/translate-a64.c              |  42 ++--
 target/arm/tcg/translate.c                  |  34 +--
 tests/functional/arm/test_aspeed_anacapa.py |   4 +-
 14 files changed, 331 insertions(+), 73 deletions(-)

-- 
2.47.3