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/cris/helper.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/target/cris/helper.c b/target/cris/helper.c index 67946d9246..22aecde0f5 100644 --- a/target/cris/helper.c +++ b/target/cris/helper.c @@ -45,8 +45,10 @@ void cris_cpu_do_interrupt(CPUState *cs) CRISCPU *cpu = CRIS_CPU(cs); CPUCRISState *env = &cpu->env; + qemu_mutex_lock_iothread(); cs->exception_index = -1; env->pregs[PR_ERP] = env->pc; + qemu_mutex_unlock_iothread(); } void crisv10_cpu_do_interrupt(CPUState *cs) @@ -128,6 +130,10 @@ void crisv10_cpu_do_interrupt(CPUState *cs) CRISCPU *cpu = CRIS_CPU(cs); CPUCRISState *env = &cpu->env; int ex_vec = -1; + bool bql = !qemu_mutex_iothread_locked(); + if (bql) { + qemu_mutex_lock_iothread(); + } D_LOG("exception index=%d interrupt_req=%d\n", cs->exception_index, @@ -183,6 +189,9 @@ void crisv10_cpu_do_interrupt(CPUState *cs) env->pregs[PR_CCS], env->pregs[PR_PID], env->pregs[PR_ERP]); + if (bql) { + qemu_mutex_unlock_iothread(); + } } void cris_cpu_do_interrupt(CPUState *cs) @@ -190,6 +199,10 @@ void cris_cpu_do_interrupt(CPUState *cs) CRISCPU *cpu = CRIS_CPU(cs); CPUCRISState *env = &cpu->env; int ex_vec = -1; + bool bql = !qemu_mutex_iothread_locked(); + if (bql) { + qemu_mutex_lock_iothread(); + } D_LOG("exception index=%d interrupt_req=%d\n", cs->exception_index, @@ -265,6 +278,9 @@ void cris_cpu_do_interrupt(CPUState *cs) env->pregs[PR_CCS], env->pregs[PR_PID], env->pregs[PR_ERP]); + if (bql) { + qemu_mutex_unlock_iothread(); + } } hwaddr cris_cpu_get_phys_page_debug(CPUState *cs, vaddr addr) @@ -294,6 +310,7 @@ bool cris_cpu_exec_interrupt(CPUState *cs, int interrupt_request) CRISCPU *cpu = CRIS_CPU(cs); CPUCRISState *env = &cpu->env; bool ret = false; + qemu_mutex_lock_iothread(); if (interrupt_request & CPU_INTERRUPT_HARD && (env->pregs[PR_CCS] & I_FLAG) @@ -315,6 +332,7 @@ bool cris_cpu_exec_interrupt(CPUState *cs, int interrupt_request) ret = true; } } + qemu_mutex_unlock_iothread(); return ret; } -- 2.17.1