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Re: [Qemu-devel] [RFC v1 10/11] tcg: grab iothread lock in cpu-exec inte
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [RFC v1 10/11] tcg: grab iothread lock in cpu-exec interrupt handling |
Date: |
Tue, 22 Mar 2016 12:03:27 +0000 |
User-agent: |
mu4e 0.9.17; emacs 25.0.92.7 |
Paolo Bonzini <address@hidden> writes:
> On 18/03/2016 17:18, Alex Bennée wrote:
>> From: "Emilio G. Cota" <address@hidden>
>>
>> Signed-off-by: Emilio G. Cota <address@hidden>
>> Signed-off-by: Alex Bennée <address@hidden>
>>
>> ---
>> v1 (ajb)
>> - pulled from emilio/mttcg series
>> ---
>> cpu-exec.c | 33 +++++++++++++++++++++++++++------
>> include/qom/cpu.h | 1 +
>> 2 files changed, 28 insertions(+), 6 deletions(-)
>>
>> diff --git a/cpu-exec.c b/cpu-exec.c
>> index 76891fd..6acaf25 100644
>> --- a/cpu-exec.c
>> +++ b/cpu-exec.c
>> @@ -351,6 +351,29 @@ static void cpu_handle_debug_exception(CPUState *cpu)
>> cc->debug_excp_handler(cpu);
>> }
>>
>> +#ifdef CONFIG_SOFTMMU
>> +static inline void cpu_exit_loop_lock(CPUState *cpu)
>> +{
>> + qemu_mutex_lock_iothread();
>> + cpu->cpu_loop_exit_locked = true;
>> +}
>> +
>> +static inline void cpu_exit_loop_lock_reset(CPUState *cpu)
>> +{
>> + if (cpu->cpu_loop_exit_locked) {
>> + cpu->cpu_loop_exit_locked = false;
>> + qemu_mutex_unlock_iothread();
>> + }
>> +}
>
> In the meanwhile we got qemu_mutex_iothread_locked(), so these two
> inlines are not necessary anymore.
Good point, I'll fix that up as I squash them.
>
> Paolo
>
>> +#else
>> +static inline void cpu_exit_loop_lock(CPUState *cpu)
>> +{ }
>> +
>> +static inline void cpu_exit_loop_lock_reset(CPUState *cpu)
>> +{ }
>> +#endif
>> +
>> /* main execution loop */
>>
>> int cpu_exec(CPUState *cpu)
>> @@ -450,12 +473,7 @@ int cpu_exec(CPUState *cpu)
>> for(;;) {
>> interrupt_request = cpu->interrupt_request;
>> if (unlikely(interrupt_request)) {
>> - /* FIXME: this needs to take the iothread lock.
>> - * For this we need to find all places in
>> - * cc->cpu_exec_interrupt that can call cpu_loop_exit,
>> - * and call qemu_unlock_iothread_mutex() there. Else,
>> - * add a flag telling cpu_loop_exit() to unlock it.
>> - */
>> + cpu_exit_loop_lock(cpu);
>>
>> if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
>> /* Mask out external interrupts for this step. */
>> @@ -510,6 +528,8 @@ int cpu_exec(CPUState *cpu)
>> next_tb = 0;
>> }
>>
>> + cpu_exit_loop_lock_reset(cpu);
>> +
>> }
>> if (unlikely(cpu->exit_request
>> || replay_has_interrupt())) {
>> @@ -630,6 +650,7 @@ int cpu_exec(CPUState *cpu)
>>
>> cpu->can_do_io = 1;
>> tb_lock_reset();
>> + cpu_exit_loop_lock_reset(cpu);
>> }
>> } /* for(;;) */
>>
>> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
>> index d6cb7b8..954d97d 100644
>> --- a/include/qom/cpu.h
>> +++ b/include/qom/cpu.h
>> @@ -295,6 +295,7 @@ struct CPUState {
>> bool crash_occurred;
>> bool exit_request;
>> bool tb_invalidated_flag;
>> + bool cpu_loop_exit_locked;
>> uint32_t interrupt_request;
>> int singlestep_enabled;
>> int64_t icount_extra;
>>
--
Alex Bennée
[Qemu-devel] [RFC v1 04/11] tcg: protect TBContext with tb_lock., Alex Bennée, 2016/03/18
[Qemu-devel] [RFC v1 08/11] tcg: add kick timer for single-threaded vCPU emulation, Alex Bennée, 2016/03/18
[Qemu-devel] [RFC v1 07/11] tcg: add options for enabling MTTCG, Alex Bennée, 2016/03/18
[Qemu-devel] [RFC v1 10/11] tcg: grab iothread lock in cpu-exec interrupt handling, Alex Bennée, 2016/03/18
[Qemu-devel] [RFC v1 11/11] tcg: enable thread-per-vCPU, Alex Bennée, 2016/03/18
[Qemu-devel] [RFC v1 09/11] tcg: drop global lock during TCG code execution, Alex Bennée, 2016/03/18