[PATCH v3 0/4] powerpc/64s: idle POWER9 stop improvements

[Nicholas Piggin <npiggin@gmail.com>]

These are rebased patches leftover from the unmerged bit of
the idle series.

Based on feedback, I dropped one of the KVM patches, and reworked
the code a bit so it is easier to restore the ability for KVM to
grab secondaries into real mode.

I did a bit more benchmarking, and all up these patches improve 2
CPU ping-pong context switch benchmark on a POWER9 by around 4-6%
(depending on what CPUs and idle states are used).

Nicholas Piggin (4):
  KVM: PPC: Book3S HV: POWER9 does not require secondary thread
    management
  powerpc/64s: idle POWER9 can execute stop without a sync sequence
  powerpc/64s: idle POWER9 can execute stop in virtual mode
  powerpc/64s: idle ESL=0 stop can avoid MSR and save/restore overhead

 arch/powerpc/include/asm/cpuidle.h        |  16 -----
 arch/powerpc/include/asm/kvm_book3s_asm.h |   4 ++
 arch/powerpc/kernel/idle_book3s.S         | 103 ++++++++++++++++++++++--------
 arch/powerpc/kvm/book3s_hv.c              |  14 +++-
 arch/powerpc/kvm/book3s_hv_rmhandlers.S   |   8 +++
 5 files changed, 101 insertions(+), 44 deletions(-)

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2.13.3