On 05/08/20 21:18, Richard Henderson wrote: > On 8/5/20 11:12 AM, Robert Foley wrote: >> This change removes the implied BQL from the cpu_handle_interrupt, >> and cpu_handle_exception paths. This BQL acquire is being pushed >> down into the per arch implementation. >> >> Signed-off-by: Robert Foley <robert.fo...@linaro.org> >> --- >> accel/tcg/cpu-exec.c | 19 +++++++++++-------- >> 1 file changed, 11 insertions(+), 8 deletions(-) >> >> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c >> index 80d0e649b2..8e2bfd97a1 100644 >> --- a/accel/tcg/cpu-exec.c >> +++ b/accel/tcg/cpu-exec.c >> @@ -517,9 +517,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, >> int *ret) >> #else >> if (replay_exception()) { >> CPUClass *cc = CPU_GET_CLASS(cpu); >> - qemu_mutex_lock_iothread(); >> cc->do_interrupt(cpu); >> - qemu_mutex_unlock_iothread(); >> cpu->exception_index = -1; >> > > This patch is not bisectable. The removal of the lock here needs to happen at > the end, or something.
Indeed the series should be structured like this: 1) rename all *_do_interrupt functions to *_do_interrupt_locked 2) add back *_do_interrupt that takes the BQL and calls *_do_interrupt_locked, point ->do_interrupt to it, remove the BQL from cpu-exec.c 3) modify the cpu_mutex and BQL critical sections around ->cpu_exec_interrupt, so that the BQL critical section covers just the call to ->cpu_exec_interrupt. Document which fields are now covered by cpu_mutex. 4/5) same as 1/2 for ->cpu_exec_interrupt Patches 1/2 would be pretty large, but they're trivial to review just by grepping for "->do_interrupt\s*=", and likewise for 4/5. Thanks, Paolo