[v1] target/arm: Improve user-mode compatibility with JITs

[PATCH 0/2] target/arm: Improve user-mode compatibility with JITs

John Högberg posted 2 patches 11 months, 1 week ago

Diff against v2 v3 v4
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target/arm/helper.c               |  47 ++++++-
tests/tcg/aarch64/Makefile.target |   3 +-
tests/tcg/aarch64/icivau.c        | 204 ++++++++++++++++++++++++++++++
3 files changed, 250 insertions(+), 4 deletions(-)
create mode 100644 tests/tcg/aarch64/icivau.c

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[PATCH 0/2] target/arm: Improve user-mode compatibility with JITs

Posted by John Högberg 11 months, 1 week ago

When running in user-mode QEMU currently fails to emulate JITs that
use dual-mapped code to get around W^X restrictions, where one mapping
is writable and one is executable. As it has no way of knowing that a
write to the writable region is reflected in the executable one, it
fails to invalidate previously translated code which leads to a crash
at best.

(Note that system mode is unaffected as the softmmu is fully aware of
what is going on.)

This patch series catches changes to dual-mapped code by honoring the
cache management instructions required to make things work on actual
hardware.

See https://gitlab.com/qemu-project/qemu/-/issues/1034 for more details

John Högberg (2):
  target/arm: Handle IC IVAU to improve compatibility with JITs
  tests/tcg/aarch64: Add testcases for IC IVAU and dual-mapped code

 target/arm/helper.c               |  47 ++++++-
 tests/tcg/aarch64/Makefile.target |   3 +-
 tests/tcg/aarch64/icivau.c        | 204 ++++++++++++++++++++++++++++++
 3 files changed, 250 insertions(+), 4 deletions(-)
 create mode 100644 tests/tcg/aarch64/icivau.c

-- 
2.34.1