Re: [PATCH 03/11] i386/hvf: Don't send signal to thread when kicking

[Roman Bolshakov]

On 10.12.2024 04:22, Philippe Mathieu-Daudé wrote:
> On 9/12/24 21:36, phil@philjordan.eu wrote:
>> From: Phil Dennis-Jordan <phil@philjordan.eu>
>>
>> This seems to be entirely superfluous and is costly enough to show up in
>
> So the pthread_kill(cpu->thread, SIG_IPI) is entirely superfluous?
>
>> profiling. hv_vcpu_interrupt() has been demonstrated to very reliably
>> cause VM exits - even if the target vCPU isn't even running, it will
>> immediately exit on entry.
>>
>> Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
>> ---
>>   target/i386/hvf/hvf.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
>> index 3b6ee79fb2..936c31dbdd 100644
>> --- a/target/i386/hvf/hvf.c
>> +++ b/target/i386/hvf/hvf.c
>> @@ -214,7 +214,7 @@ static inline bool 
>> apic_bus_freq_is_known(CPUX86State *env)
>>     void hvf_kick_vcpu_thread(CPUState *cpu)
>>   {
>> -    cpus_kick_thread(cpu);
>> +    cpu->thread_kicked = true;
>>       hv_vcpu_interrupt(&cpu->accel->fd, 1);
>>   }
>
SIG_IPI is macOS crutch handled in XNU kernel that was essential until 
Phil submitted proper kick support with hv_vcpu_interrupt().