This is part of a series of changes to remove the implied BQL from the common code of cpu_handle_interrupt and cpu_handle_exception. As part of removing the implied BQL from the common code, we are pushing the BQL holding down into the per-arch implementation functions of do_interrupt and cpu_exec_interrupt.
The purpose of this set of changes is to set the groundwork so that an arch could move towards removing the BQL from the cpu_handle_interrupt/exception paths. 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/2020-07/msg08731.html https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg00044.html Signed-off-by: Robert Foley <robert.fo...@linaro.org> --- target/rx/helper.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/target/rx/helper.c b/target/rx/helper.c index a6a337a311..a456b727ed 100644 --- a/target/rx/helper.c +++ b/target/rx/helper.c @@ -48,6 +48,10 @@ void rx_cpu_do_interrupt(CPUState *cs) CPURXState *env = &cpu->env; int do_irq = cs->interrupt_request & INT_FLAGS; uint32_t save_psw; + bool bql = !qemu_mutex_iothread_locked(); + if (bql) { + qemu_mutex_lock_iothread(); + } env->in_sleep = 0; @@ -117,6 +121,9 @@ void rx_cpu_do_interrupt(CPUState *cs) (vec & 0xff), expname); } env->regs[0] = env->isp; + if (bql) { + qemu_mutex_unlock_iothread(); + } } bool rx_cpu_exec_interrupt(CPUState *cs, int interrupt_request) @@ -124,6 +131,7 @@ bool rx_cpu_exec_interrupt(CPUState *cs, int interrupt_request) RXCPU *cpu = RXCPU(cs); CPURXState *env = &cpu->env; int accept = 0; + qemu_mutex_lock_iothread(); /* hardware interrupt (Normal) */ if ((interrupt_request & CPU_INTERRUPT_HARD) && env->psw_i && (env->psw_ipl < env->req_ipl)) { @@ -138,8 +146,10 @@ bool rx_cpu_exec_interrupt(CPUState *cs, int interrupt_request) } if (accept) { rx_cpu_do_interrupt(cs); + qemu_mutex_unlock_iothread(); return true; } + qemu_mutex_unlock_iothread(); return false; } -- 2.17.1
