Re: [PATCH v2 2/7] target/arm: add ARMCPUClass->do_interrupt_locked

[Richard Henderson]

On 8/19/20 11:28 AM, Robert Foley wrote:
> Adding ->do_interrupt_locked to ARMCPUClass is preparation for
> pushing the BQL down into the per-arch implementation of ->do_interrupt.
> 
> This is needed since ARM's *_cpu_exec_interrupt calls to *_do_interrupt.
> With the push down of the BQL into *_cpu_exec_interrupt and
> *_do_interrupt, *_cpu_exec_interrupt will call to ->do_interrupt
> with lock held.  Since ->do_interrupt also has the lock, we need a way
> to allow cpu_exec_interrupt to call do_interrupt with lock held.
> This patch solves this issue of *_cpu_exec_interrupt needing
> to call do_interrupt with lock held.
> 
> This patch is part of a series of transitions to move the
> BQL down into the do_interrupt per arch functions.  This set of
> transitions is needed to maintain bisectability.
> 
> This approach was suggested by Paolo Bonzini.
> For reference, here are two key posts in the discussion, explaining
> the reasoning/benefits of this approach.
> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg00784.html
> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg01517.html
> https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg08731.html
> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg00044.html
> 
> Signed-off-by: Robert Foley <robert.foley@linaro.org>
> ---
>  target/arm/cpu-qom.h | 3 +++
>  target/arm/cpu.c     | 5 +++--
>  target/arm/cpu_tcg.c | 5 +++--
>  3 files changed, 9 insertions(+), 4 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~