Re: [Qemu-devel] [PULL 00/24] MTTCG Base enabling patches with ARM enablement

["Alex Bennée" <alex.bennee@linaro.org>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 24/02/2017 12:20, Alex Bennée wrote:
>> The following changes since commit 2d896b454a0e19ec4c1ddbb0e0b65b7e54fcedf3:
>>
>>   Revert "hw/mips: MIPS Boston board support" (2017-02-23 18:04:45 +0000)
>>
>> are available in the git repository at:
>>
>>   https://github.com/stsquad/qemu.git tags/pull-mttcg-240217-1
>>
>> for you to fetch changes up to ca759f9e387db87e1719911f019bc60c74be9ed8:
>>
>>   tcg: enable MTTCG by default for ARM on x86 hosts (2017-02-24 10:32:46 +0000)
>>
>> ----------------------------------------------------------------
>> This is the MTTCG pull-request as posted yesterday.
>
> This breaks "-icount auto" on qemu-system-aarch64 with "-M virt" and
> AAVMF firmware, in two ways:
>
> 1) "-icount auto" doesn't work;

Currently the code does:

  static bool default_mttcg_enabled(void)
  {
      QemuOpts *icount_opts = qemu_find_opts_singleton("icount");
      const char *rr = qemu_opt_get(icount_opts, "rr");

      if (rr || TCG_OVERSIZED_GUEST) {
          return false;

I suspect I should just fail if any icount options are set. However
qemu_find_opts_singleton always returns the structure. How do I test
for any icount options?

>
> 2) "-icount auto -accel tcg,thread=single" hangs fairly early, printing
> this on the serial console.  It's okay if it hangs at
>
> [Bds]=============End Load Options Dumping=============
> [Bds]BdsWait ...Zzzzzzzzzzzz...
> [Bds]BdsWait(3)..Zzzz...
>
> (pressing Enter a few times then seems to unhang it), but it now hangs
> much earlier than that.

Hmm I can see a hang on linux booting like that. It looks like a vCPU
get stuck in waitio and never schedules the others.

>
>
> Also, x86 "-accel tcg,thread=multi" prints the scary message on memory
> ordering.

That is expected until x86 is properly tested and we submit the default
enabling patch for x86 on x86. To be honest we could submit the MO patch
now to make that warning go away.

>
> Paolo
>
>> ----------------------------------------------------------------
>> Alex Bennée (18):
>>       docs: new design document multi-thread-tcg.txt
>>       tcg: move TCG_MO/BAR types into own file
>>       tcg: add kick timer for single-threaded vCPU emulation
>>       tcg: rename tcg_current_cpu to tcg_current_rr_cpu
>>       tcg: remove global exit_request
>>       tcg: enable tb_lock() for SoftMMU
>>       tcg: enable thread-per-vCPU
>>       cputlb: add assert_cpu_is_self checks
>>       cputlb: tweak qemu_ram_addr_from_host_nofail reporting
>>       cputlb and arm/sparc targets: convert mmuidx flushes from varg to bitmap
>>       cputlb: add tlb_flush_by_mmuidx async routines
>>       cputlb: atomically update tlb fields used by tlb_reset_dirty
>>       cputlb: introduce tlb_flush_*_all_cpus[_synced]
>>       target-arm/powerctl: defer cpu reset work to CPU context
>>       target-arm: don't generate WFE/YIELD calls for MTTCG
>>       target-arm: ensure all cross vCPUs TLB flushes complete
>>       hw/misc/imx6_src: defer clearing of SRC_SCR reset bits
>>       tcg: enable MTTCG by default for ARM on x86 hosts
>>
>> Jan Kiszka (1):
>>       tcg: drop global lock during TCG code execution
>>
>> KONRAD Frederic (2):
>>       tcg: add options for enabling MTTCG
>>       cputlb: introduce tlb_flush_* async work.
>>
>> Pranith Kumar (3):
>>       mttcg: translate-all: Enable locking debug in a debug build
>>       mttcg: Add missing tb_lock/unlock() in cpu_exec_step()
>>       tcg: handle EXCP_ATOMIC exception for system emulation
>>
>>  configure                  |   6 +
>>  cpu-exec-common.c          |   3 -
>>  cpu-exec.c                 |  89 ++++++---
>>  cpus.c                     | 345 ++++++++++++++++++++++++++-------
>>  cputlb.c                   | 463 +++++++++++++++++++++++++++++++++++++--------
>>  docs/multi-thread-tcg.txt  | 350 ++++++++++++++++++++++++++++++++++
>>  exec.c                     |  12 +-
>>  hw/core/irq.c              |   1 +
>>  hw/i386/kvmvapic.c         |   4 +-
>>  hw/intc/arm_gicv3_cpuif.c  |   3 +
>>  hw/misc/imx6_src.c         |  58 +++++-
>>  hw/ppc/ppc.c               |  16 +-
>>  hw/ppc/spapr.c             |   3 +
>>  include/exec/cputlb.h      |   2 -
>>  include/exec/exec-all.h    | 132 +++++++++++--
>>  include/qom/cpu.h          |  16 ++
>>  include/sysemu/cpus.h      |   2 +
>>  memory.c                   |   2 +
>>  qemu-options.hx            |  20 ++
>>  qom/cpu.c                  |  10 +
>>  target/arm/arm-powerctl.c  | 202 +++++++++++++-------
>>  target/arm/arm-powerctl.h  |   2 +
>>  target/arm/cpu.c           |   4 +-
>>  target/arm/cpu.h           |  18 +-
>>  target/arm/helper.c        | 219 ++++++++++-----------
>>  target/arm/kvm.c           |   7 +-
>>  target/arm/machine.c       |  41 +++-
>>  target/arm/op_helper.c     |  50 ++++-
>>  target/arm/psci.c          |   4 +-
>>  target/arm/translate-a64.c |   8 +-
>>  target/arm/translate.c     |  20 +-
>>  target/i386/smm_helper.c   |   7 +
>>  target/s390x/misc_helper.c |   5 +-
>>  target/sparc/ldst_helper.c |   8 +-
>>  tcg/i386/tcg-target.h      |  11 ++
>>  tcg/tcg-mo.h               |  48 +++++
>>  tcg/tcg.h                  |  27 +--
>>  translate-all.c            |  66 ++-----
>>  translate-common.c         |  21 +-
>>  vl.c                       |  49 ++++-
>>  40 files changed, 1878 insertions(+), 476 deletions(-)
>>  create mode 100644 docs/multi-thread-tcg.txt
>>  create mode 100644 tcg/tcg-mo.h
>>
>>


--
Alex Bennée