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[v2,00/27] accel/tcg: Improvements to atomic128.h

Message ID 20230523134733.678646-1-richard.henderson@linaro.org
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Series accel/tcg: Improvements to atomic128.h | expand

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Richard Henderson May 23, 2023, 1:47 p.m. UTC 
Peter raised a good point about it not being ideal to mix inline assembly
into the middle of accel/tcg/ldst_atomicity.c.  We now have a host-specific
structure in which to put those.

Additionally, Peter noticed that clang will incorrectly use a read-write
sequence for __atomic_load_16 on AArch64, which might fault for our usage
in user-only emulation.

Fixing both of these simultaneously splits atomic16_read into
atomic16_read_{ro,rw}, because there is in fact room for both
in the emulation -- we currently use cmpxchg directly where we
can allow a read with write side-effect.

Additionally, prepare for runtime detection.  Both x86_64 and aarch64
have architecture extensions that *do* allow 128-bit load and store
without using cmpxchg.

To make runtime detection work, we need to remove preprocessor use
of HAVE_ATOMIC128*.  It turns out this was only used for the legacy
helper_atomic_{ld,st}o_{be,le}_mmu functions.  These uses within
ppc64 and s390x can now be updated to tcg_gen_qemu_{ld,st}_i128 and
cpu_{ld,st}16_mmu.  After doing that, we can remove the problematic
#if's entirely.

Changes for v2:
  * Updates from review.

Patches requiring review:
  05-util-bufferiszero-Use-i386-host-cpuinfo.h.patch
  10-include-host-Split-out-atomic128-cas.h.patch
  11-include-host-Split-out-atomic128-ldst.h.patch
  13-include-qemu-Move-CONFIG_ATOMIC128_OPT-handling-t.patch
  14-target-ppc-Use-tcg_gen_qemu_-ld-st-_i128-for-LQAR.patch
  15-target-s390x-Use-tcg_gen_qemu_-ld-st-_i128-for-LP.patch
  17-target-s390x-Use-cpu_-ld-st-_mmu-in-do_csst.patch
  19-accel-tcg-Remove-cpu_atomic_-ld-st-o_-_mmu.patch
  20-accel-tcg-Remove-prot-argument-to-atomic_mmu_look.patch
  21-accel-tcg-Eliminate-if-on-HAVE_ATOMIC128-and-HAVE.patch
  22-qemu-atomic128-Split-atomic16_read.patch
  23-accel-tcg-Correctly-use-atomic128.h-in-ldst_atomi.patch
  25-qemu-atomic128-Improve-cmpxchg-fallback-for-atomi.patch
  26-qemu-atomic128-Add-runtime-test-for-FEAT_LSE2.patch
  27-qemu-atomic128-Add-x86_64-atomic128-ldst.h.patch


r~


Cc: qemu-ppc@nongnu.org
Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
Cc: "Cédric Le Goater" <clg@kaod.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Greg Kurz <groug@kaod.org>

Cc: qemu-s390x@nongnu.org
Cc: David Hildenbrand <david@redhat.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>

Richard Henderson (27):
  util: Introduce host-specific cpuinfo.h
  util: Add cpuinfo-i386.c
  util: Add i386 CPUINFO_ATOMIC_VMOVDQU
  tcg/i386: Use host/cpuinfo.h
  util/bufferiszero: Use i386 host/cpuinfo.h
  migration/xbzrle: Shuffle function order
  migration/xbzrle: Use i386 host/cpuinfo.h
  migration: Build migration_files once
  util: Add cpuinfo-aarch64.c
  include/host: Split out atomic128-cas.h
  include/host: Split out atomic128-ldst.h
  meson: Fix detect atomic128 support with optimization
  include/qemu: Move CONFIG_ATOMIC128_OPT handling to atomic128.h
  target/ppc: Use tcg_gen_qemu_{ld,st}_i128 for LQARX, LQ, STQ
  target/s390x: Use tcg_gen_qemu_{ld,st}_i128 for LPQ, STPQ
  accel/tcg: Unify cpu_{ld,st}*_{be,le}_mmu
  target/s390x: Use cpu_{ld,st}*_mmu in do_csst
  target/s390x: Always use cpu_atomic_cmpxchgl_be_mmu in do_csst
  accel/tcg: Remove cpu_atomic_{ld,st}o_*_mmu
  accel/tcg: Remove prot argument to atomic_mmu_lookup
  accel/tcg: Eliminate #if on HAVE_ATOMIC128 and HAVE_CMPXCHG128
  qemu/atomic128: Split atomic16_read
  accel/tcg: Correctly use atomic128.h in ldst_atomicity.c.inc
  tcg: Split out tcg/debug-assert.h
  qemu/atomic128: Improve cmpxchg fallback for atomic16_set
  qemu/atomic128: Add runtime test for FEAT_LSE2
  qemu/atomic128: Add x86_64 atomic128-ldst.h

 accel/tcg/atomic_template.h                |  93 +---
 host/include/aarch64/host/atomic128-cas.h  |  45 ++
 host/include/aarch64/host/atomic128-ldst.h |  79 ++++
 host/include/aarch64/host/cpuinfo.h        |  22 +
 host/include/generic/host/atomic128-cas.h  |  47 +++
 host/include/generic/host/atomic128-ldst.h |  81 ++++
 host/include/generic/host/cpuinfo.h        |   4 +
 host/include/i386/host/cpuinfo.h           |  39 ++
 host/include/x86_64/host/atomic128-ldst.h  |  54 +++
 host/include/x86_64/host/cpuinfo.h         |   1 +
 include/exec/cpu_ldst.h                    |  67 +--
 include/qemu/atomic128.h                   | 146 +------
 include/tcg/debug-assert.h                 |  17 +
 include/tcg/tcg.h                          |   9 +-
 migration/xbzrle.h                         |   5 +-
 target/ppc/cpu.h                           |   1 -
 target/ppc/helper.h                        |   9 -
 target/s390x/cpu.h                         |   3 -
 target/s390x/helper.h                      |   4 -
 tcg/aarch64/tcg-target.h                   |   6 +-
 tcg/i386/tcg-target.h                      |  28 +-
 accel/tcg/cputlb.c                         | 211 +++------
 accel/tcg/user-exec.c                      | 332 ++++-----------
 migration/ram.c                            |  34 +-
 migration/xbzrle.c                         | 268 ++++++------
 target/arm/tcg/m_helper.c                  |   4 +-
 target/ppc/mem_helper.c                    |  48 ---
 target/ppc/translate.c                     |  34 +-
 target/s390x/tcg/mem_helper.c              | 137 ++----
 target/s390x/tcg/translate.c               |  30 +-
 target/sparc/ldst_helper.c                 |  18 +-
 tests/bench/xbzrle-bench.c                 | 469 ---------------------
 tests/unit/test-xbzrle.c                   |  49 +--
 util/bufferiszero.c                        | 126 ++----
 util/cpuinfo-aarch64.c                     |  67 +++
 util/cpuinfo-i386.c                        |  99 +++++
 MAINTAINERS                                |   1 +
 accel/tcg/atomic_common.c.inc              |  14 -
 accel/tcg/ldst_atomicity.c.inc             | 135 +-----
 accel/tcg/ldst_common.c.inc                |  24 +-
 meson.build                                |  12 +-
 migration/meson.build                      |   1 -
 target/ppc/translate/fixedpoint-impl.c.inc |  51 +--
 target/s390x/tcg/insn-data.h.inc           |   2 +-
 tcg/aarch64/tcg-target.c.inc               |  40 --
 tcg/i386/tcg-target.c.inc                  | 123 +-----
 tests/bench/meson.build                    |   6 -
 util/meson.build                           |   6 +
 48 files changed, 1085 insertions(+), 2016 deletions(-)
 create mode 100644 host/include/aarch64/host/atomic128-cas.h
 create mode 100644 host/include/aarch64/host/atomic128-ldst.h
 create mode 100644 host/include/aarch64/host/cpuinfo.h
 create mode 100644 host/include/generic/host/atomic128-cas.h
 create mode 100644 host/include/generic/host/atomic128-ldst.h
 create mode 100644 host/include/generic/host/cpuinfo.h
 create mode 100644 host/include/i386/host/cpuinfo.h
 create mode 100644 host/include/x86_64/host/atomic128-ldst.h
 create mode 100644 host/include/x86_64/host/cpuinfo.h
 create mode 100644 include/tcg/debug-assert.h
 delete mode 100644 tests/bench/xbzrle-bench.c
 create mode 100644 util/cpuinfo-aarch64.c
 create mode 100644 util/cpuinfo-i386.c