Re: [PATCH for-8.0 4/7] target/ppc: Use QEMU_IOTHREAD_LOCK_GUARD in cpu_interrupt_exittb

[Richard Henderson <richard.henderson@linaro.org>]

On 11/18/22 02:13, Daniel Henrique Barboza wrote:
> 
> 
> On 11/18/22 06:18, Richard Henderson wrote:
>> In addition, use tcg_enabled instead of !kvm_enabled.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
> 
> Should we strive for this change (tcg_enabled instead of !kvm_enabled)
> everywhere when applicable? There's a lot of places in the ppc code where
> this can be done.

I think it's better style, since that's generally what is meant.

It's important when the target supports multiple accelerators.  A test for !kvm begs the 
question of why we aren't also testing for e.g. !hvf.  I've noticed a couple of these in 
the code base.


r~

> 
> 
> Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> 
> 
>> Cc: qemu-ppc@nongnu.org
>> ---
>>   target/ppc/helper_regs.c | 14 ++++----------
>>   1 file changed, 4 insertions(+), 10 deletions(-)
>>
>> diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
>> index c0aee5855b..779e7db513 100644
>> --- a/target/ppc/helper_regs.c
>> +++ b/target/ppc/helper_regs.c
>> @@ -22,6 +22,7 @@
>>   #include "qemu/main-loop.h"
>>   #include "exec/exec-all.h"
>>   #include "sysemu/kvm.h"
>> +#include "sysemu/tcg.h"
>>   #include "helper_regs.h"
>>   #include "power8-pmu.h"
>>   #include "cpu-models.h"
>> @@ -203,17 +204,10 @@ void cpu_interrupt_exittb(CPUState *cs)
>>   {
>>       /*
>>        * We don't need to worry about translation blocks
>> -     * when running with KVM.
>> +     * unless running with TCG.
>>        */
>> -    if (kvm_enabled()) {
>> -        return;
>> -    }
>> -
>> -    if (!qemu_mutex_iothread_locked()) {
>> -        qemu_mutex_lock_iothread();
>> -        cpu_interrupt(cs, CPU_INTERRUPT_EXITTB);
>> -        qemu_mutex_unlock_iothread();
>> -    } else {
>> +    if (tcg_enabled()) {
>> +        QEMU_IOTHREAD_LOCK_GUARD();
>>           cpu_interrupt(cs, CPU_INTERRUPT_EXITTB);
>>       }
>>   }