Historically, M-profile helper functions in m_helper.c and mve_helper.c
used the unaligned cpu_*_data_ra() routines to perform guest memory
accesses. This meant we had no way to enforce alignment constraints
when executing helper-based loads/stores. With the addition of the
cpu_*_mmu() APIs, we can now combine the current MMU state with MO_ALIGN
flags to build a MemOpIdx that enforces alignment at the helper level.

This patch series:
- Replaces all calls to cpu_ld*_data_ra(), cpu_st*_data_ra()
  in the M-profile helpers (m_helper.c) and the MVE helpers
  (mve_helper.c) with their cpu_*_mmu() equivalents.
- Leaves SME and SVE helper code untouched, as those extensions
  support unaligned accesses by design.

With this change, all M-profile and MVE helper-based loads and stores
will now correctly honor their alignment requirements.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1154
Signed-off-by: William Kosasih <kosasihwilliam4@gmail.com>

William Kosasih (11):
  target/arm: Bring VLSTM/VLLDM helper store/load closer to the ARM
    pseudocode
  target/arm: Fix BLXNS helper store alignment checks
  target/arm: Fix function_return helper load alignment checks
  target/arm: Fix VLDR helper load alignment checks
  target/arm: Fix VSTR helper store alignment checks
  target/arm: Fix VLDR_SG helper load alignment checks
  target/arm: Fix VSTR_SG helper store alignment checks
  target/arm: Fix VLD4 helper load alignment checks
  target/arm: Fix VLD2 helper load alignment checks
  target/arm: Fix VST4 helper store alignment checks
  target/arm: Fix VST2 helper store alignment checks

 target/arm/tcg/m_helper.c   |  33 +++++---
 target/arm/tcg/mve_helper.c | 162 ++++++++++++++++++++++--------------
 2 files changed, 122 insertions(+), 73 deletions(-)

-- 
2.48.1

On Thu, 3 Jul 2025 at 09:56, William Kosasih <kosasihwilliam4@gmail.com> wrote:
>
> Historically, M-profile helper functions in m_helper.c and mve_helper.c
> used the unaligned cpu_*_data_ra() routines to perform guest memory
> accesses. This meant we had no way to enforce alignment constraints
> when executing helper-based loads/stores. With the addition of the
> cpu_*_mmu() APIs, we can now combine the current MMU state with MO_ALIGN
> flags to build a MemOpIdx that enforces alignment at the helper level.
>
> This patch series:
> - Replaces all calls to cpu_ld*_data_ra(), cpu_st*_data_ra()
>   in the M-profile helpers (m_helper.c) and the MVE helpers
>   (mve_helper.c) with their cpu_*_mmu() equivalents.
> - Leaves SME and SVE helper code untouched, as those extensions
>   support unaligned accesses by design.
>
> With this change, all M-profile and MVE helper-based loads and stores
> will now correctly honor their alignment requirements.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1154
> Signed-off-by: William Kosasih <kosasihwilliam4@gmail.com>

Applied to target-arm.next. Thanks for these patches!

-- PMM

This really made my day :-) Thanks Peter!

Best regards,
William

On Fri, Jul 4, 2025 at 22:29 Peter Maydell <peter.maydell@linaro.org> wrote:

> On Thu, 3 Jul 2025 at 09:56, William Kosasih <kosasihwilliam4@gmail.com>
> wrote:
> >
> > Historically, M-profile helper functions in m_helper.c and mve_helper.c
> > used the unaligned cpu_*_data_ra() routines to perform guest memory
> > accesses. This meant we had no way to enforce alignment constraints
> > when executing helper-based loads/stores. With the addition of the
> > cpu_*_mmu() APIs, we can now combine the current MMU state with MO_ALIGN
> > flags to build a MemOpIdx that enforces alignment at the helper level.
> >
> > This patch series:
> > - Replaces all calls to cpu_ld*_data_ra(), cpu_st*_data_ra()
> >   in the M-profile helpers (m_helper.c) and the MVE helpers
> >   (mve_helper.c) with their cpu_*_mmu() equivalents.
> > - Leaves SME and SVE helper code untouched, as those extensions
> >   support unaligned accesses by design.
> >
> > With this change, all M-profile and MVE helper-based loads and stores
> > will now correctly honor their alignment requirements.
> >
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1154
> > Signed-off-by: William Kosasih <kosasihwilliam4@gmail.com>
>
> Applied to target-arm.next. Thanks for these patches!
>
> -- PMM
>