Paolo Bonzini <pbonz...@redhat.com> writes: > On 14/06/2017 17:45, Richard Henderson wrote: >> While the next TB would detect the exit flag has been set there is no >> point if we can exit sooner. We also check cpu->interrupt_request as >> some front-ends can set it rather than using the cpu_interrupt() API >> call and would normally be expecting the IRQ to get picked up on the >> previously fairly regular exits from the run loop. > > This is not what happens actually; it's not about front-ends setting > cpu->interrupt_request, it's about front-ends doing exit_tb when they > wanted to re-evaluate cpu_handle_interrupt. > > cpu_exit is used when device code causes a rising edge in > cpu->interrupt_request. What we have here is that the MSR write causes > cc->cpu_exec_interrupt's return value to change from false to true. > > I think this is a band-aid, and would rather fix the front-ends as in > Emilio's patch.
It seems a shame to cause all msr accesses to trigger and exit when we only care about the unmasking case. How about: Author: Alex Bennée <alex.ben...@linaro.org> Date: Wed Jun 14 18:46:01 2017 +0100 target/arm/op_helper: ensure we exit the run-loop When IRQs are un-masked we need to ensure the run-loop is exited so we can evaluate arm_cpu_do_interrupt. Signed-off-by: Alex Bennée <alex.ben...@linaro.org> diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index 2a85666579..7e67bb3db2 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -835,6 +835,9 @@ void HELPER(msr_i_pstate)(CPUARMState *env, uint32_t op, uint32_t imm) break; case 0x1f: /* DAIFClear */ env->daif &= ~((imm << 6) & PSTATE_DAIF); + /* This may result in pending IRQs being unmasked so ensure we + exit the loop */ + cpu_exit(ENV_GET_CPU(env)); break; default: g_assert_not_reached();