[PATCH 0/2] target/arm: Fix unwind from dc zva and FEAT_MOPS

[Richard Henderson]

While looking into Zoltan's attempt to speed up ppc64 DCBZ
(data cache block set to zero), I wondered what AArch64 was
doing differently.  It turned out that Arm is the only user
of tlb_vaddr_to_host.

None of the code sequences in use between AArch64, Power64 and S390X
are 100% safe, with race conditions vs mmap et al, however, AArch64
is the only one that will fail this single threaded test case.  Use
of these new functions fixes the race condition as well, though I
have not yet touched the other guests.

I thought about exposing accel/tcg/user-retaddr.h for direct use
from the targets, but perhaps these wrappers are cleaner.  RFC?


r~


Richard Henderson (2):
  accel/tcg: Introduce memset_ra, memmove_ra
  target/arm: Use memset_ra, memmove_ra in helper-a64.c

 include/exec/cpu_ldst.h            | 40 ++++++++++++++++
 accel/tcg/user-exec.c              | 22 +++++++++
 target/arm/tcg/helper-a64.c        | 10 ++--
 tests/tcg/multiarch/memset-fault.c | 77 ++++++++++++++++++++++++++++++
 4 files changed, 144 insertions(+), 5 deletions(-)
 create mode 100644 tests/tcg/multiarch/memset-fault.c

-- 
2.34.1