[Qemu-devel] [PATCH 0/9] target-ppc: Rudimentary Support for Transactional Memory

[Tom Musta <tommusta@gmail.com>]

This patch series introduces rudimentary support for the Transactional Memory
(TM) feature of Power ISA V2.07.  In a nutshell, software uses the feature by
initiating a transaction via the tbegin instruction.  Hardware then accumulates
storage accesses until the transaction is committed via the tend instruction).  
At this point, either the instruction completes and all storage accesses are 
atomic with respect to other processors; or the transaction fails and processor
state reverts to the point of tbegin.  Transaction success or failure is recorded
in CR[0] and the instruction immediately following tbegin is expected to inspect
this field and provide an error path to properly handle failure.

Accurately emulating such a feature in QEMU is quite difficult.  Instead, the
approach taken here simply fails the transaction at the point of tbegin and
thus immediately takes software down the error handlling path.  As such, this can
be considered a toleration mode for any software that utilizes the TM feature.
Valgrind has taken a similar approach.  There are no immediate plans to implement
a more sophisticated model.

Currently, Power8 is the only Power processor that supports TM.

Tom Musta (9):
  target-ppc: Introduce Instruction Type for Transactional Memory
  target-ppc: Introduce Feature Flag for Transactional Memory
  target-ppc: Introduce tm_enabled Bit to CPU State
  target-ppc: Power8 Supports Transactional Memory
  target-ppc: Introduce TEXASRU Bit Fields
  target-ppc: Introduce tbegin
  target-ppc: Introduce TM Noops
  target-ppc: Introduce tcheck
  target-ppc: Introduce Privileged TM Noops

 target-ppc/cpu.h            |   26 ++++++++++-
 target-ppc/helper.h         |    2 +
 target-ppc/mem_helper.c     |   22 ++++++++
 target-ppc/translate.c      |  113 +++++++++++++++++++++++++++++++++++++++++++
 target-ppc/translate_init.c |    5 +-
 5 files changed, 165 insertions(+), 3 deletions(-)