Re: [RFC PATCH v3 15/58] perf/x86: Support switch_interrupt interface

["Mi, Dapeng" <dapeng1.mi@linux.intel.com>]

On 9/10/2024 6:11 AM, Colton Lewis wrote:
> Mingwei Zhang <mizhang@google.com> writes:
>
>> From: Kan Liang <kan.liang@linux.intel.com>
>> Implement switch_interrupt interface for x86 PMU, switch PMI to dedicated
>> KVM_GUEST_PMI_VECTOR at perf guest enter, and switch PMI back to
>> NMI at perf guest exit.
>> Signed-off-by: Xiong Zhang <xiong.y.zhang@linux.intel.com>
>> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
>> Tested-by: Yongwei Ma <yongwei.ma@intel.com>
>> Signed-off-by: Mingwei Zhang <mizhang@google.com>
>> ---
>>   arch/x86/events/core.c | 11 +++++++++++
>>   1 file changed, 11 insertions(+)
>> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
>> index 5bf78cd619bf..b17ef8b6c1a6 100644
>> --- a/arch/x86/events/core.c
>> +++ b/arch/x86/events/core.c
>> @@ -2673,6 +2673,15 @@ static bool x86_pmu_filter(struct pmu *pmu, int  
>> cpu)
>>   	return ret;
>>   }
>> +static void x86_pmu_switch_interrupt(bool enter, u32 guest_lvtpc)
>> +{
>> +	if (enter)
>> +		apic_write(APIC_LVTPC, APIC_DM_FIXED | KVM_GUEST_PMI_VECTOR |
>> +			   (guest_lvtpc & APIC_LVT_MASKED));
>> +	else
>> +		apic_write(APIC_LVTPC, APIC_DM_NMI);
>> +}
>> +
> Similar issue I point out in an earlier patch. #define
> KVM_GUEST_PMI_VECTOR is guarded by CONFIG_KVM but this code is not,
> which can result in compile errors.

Yes, thanks for pointing this.


>
>>   static struct pmu pmu = {
>>   	.pmu_enable		= x86_pmu_enable,
>>   	.pmu_disable		= x86_pmu_disable,
>> @@ -2702,6 +2711,8 @@ static struct pmu pmu = {
>>   	.aux_output_match	= x86_pmu_aux_output_match,
>>   	.filter			= x86_pmu_filter,
>> +
>> +	.switch_interrupt	= x86_pmu_switch_interrupt,
>>   };
>>   void arch_perf_update_userpage(struct perf_event *event,