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/hppa/int_helper.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/target/hppa/int_helper.c b/target/hppa/int_helper.c index 462747baf8..eda40bc5d9 100644 --- a/target/hppa/int_helper.c +++ b/target/hppa/int_helper.c @@ -94,12 +94,20 @@ void hppa_cpu_do_interrupt(CPUState *cs) { HPPACPU *cpu = HPPA_CPU(cs); CPUHPPAState *env = &cpu->env; - int i = cs->exception_index; - target_ureg iaoq_f = env->iaoq_f; - target_ureg iaoq_b = env->iaoq_b; - uint64_t iasq_f = env->iasq_f; - uint64_t iasq_b = env->iasq_b; - + int i; + target_ureg iaoq_f; + target_ureg iaoq_b; + uint64_t iasq_f; + uint64_t iasq_b; + bool bql = !qemu_mutex_iothread_locked(); + if (bql) { + qemu_mutex_lock_iothread(); + } + i = cs->exception_index; + iaoq_f = env->iaoq_f; + iaoq_b = env->iaoq_b; + iasq_f = env->iasq_f; + iasq_b = env->iasq_b; #ifndef CONFIG_USER_ONLY target_ureg old_psw; @@ -244,6 +252,9 @@ void hppa_cpu_do_interrupt(CPUState *cs) env->cr[CR_IOR])); } cs->exception_index = -1; + if (bql) { + qemu_mutex_unlock_iothread(); + } } bool hppa_cpu_exec_interrupt(CPUState *cs, int interrupt_request) @@ -251,6 +262,7 @@ bool hppa_cpu_exec_interrupt(CPUState *cs, int interrupt_request) #ifndef CONFIG_USER_ONLY HPPACPU *cpu = HPPA_CPU(cs); CPUHPPAState *env = &cpu->env; + qemu_mutex_lock_iothread(); /* If interrupts are requested and enabled, raise them. */ if ((env->psw & PSW_I) && (interrupt_request & CPU_INTERRUPT_HARD)) { @@ -258,6 +270,7 @@ bool hppa_cpu_exec_interrupt(CPUState *cs, int interrupt_request) hppa_cpu_do_interrupt(cs); return true; } + qemu_mutex_unlock_iothread(); #endif return false; } -- 2.17.1
