Re: [PATCH v5 1/2] perf/x86/amd/uncore: Add Hygon uncore PMU support

Hi

On 8/18/2026 6:16 PM, [email protected] wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Removal of Hygon L3 Uncore PMU support without a replacement in the new driver.
> --
> 
> --- Patch [1]: [PATCH v5 1/2] perf/x86/amd/uncore: Add Hygon uncore PMU support ---
> commit 1b6dd18387bea20f9f548951bf79cae006705b47
> Author: Qi Liu <[email protected]>
> 
> perf/x86/amd/uncore: Add Hygon uncore PMU support
> 
> This commit introduces a separate uncore PMU driver for Hygon processors to
> support Data Fabric (DF) and Data Fabric IO Die (DF_IOD) counters. It also
> removes the Hygon vendor checks from the AMD uncore driver to keep the
> vendor-specific features separated.
> 
>> diff --git a/arch/x86/events/amd/hygon_uncore.c b/arch/x86/events/amd/hygon_uncore.c
>> new file mode 100644
>> index 0000000000000..471955d6fc282
>> --- /dev/null
>> +++ b/arch/x86/events/amd/hygon_uncore.c
> 
> [ ... ]
> 
>> +static struct hygon_uncore uncores[HYGON_UNCORE_TYPE_MAX] = {
>> +	/* HYGON DF */
>> +	{
>> +		.scan = hygon_uncore_df_ctx_scan,
>> +		.init = hygon_uncore_df_ctx_init,
>> +		.move = hygon_uncore_ctx_move,
>> +		.free = hygon_uncore_ctx_free,
>> +	},
>> +	/* HYGON DF IOD */
>> +	{
>> +		.scan = hygon_uncore_df_iod_ctx_scan,
>> +		.init = hygon_uncore_df_iod_ctx_init,
>> +		.move = hygon_uncore_ctx_move,
>> +		.free = hygon_uncore_ctx_free,
>> +	}
>> +};
> 
> [ ... ]
> 
>> diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
>> index dbc00b6dd69ee..6c486e1ab001a 100644
>> --- a/arch/x86/events/amd/uncore.c
>> +++ b/arch/x86/events/amd/uncore.c
> 
> [ ... ]
> 
>> @@ -1120,8 +1116,7 @@ static int __init amd_uncore_init(void)
>>   	int ret = -ENODEV;
>>   	int i;
>>   
>> -	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
>> -	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
>> +	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
>>   		return -ENODEV;
>>   
>>   	if (!boot_cpu_has(X86_FEATURE_TOPOEXT))
> 
> [Severity: Medium]
> Does this inadvertently remove L3 uncore PMU support for Hygon systems?
> 
> Removing the Hygon vendor check in amd_uncore_init() prevents the AMD uncore
> driver from initializing on Hygon CPUs, which previously provided L3 cache PMU
> support.
> 
> Looking at the new driver in hygon_uncore.c, the uncores[] array only
> implements the DF and DF_IOD components. It does not appear to provide a
> replacement for the L3 cache PMU that was previously available.
> 
L3 and UMC PMU support for Hygon will be added in follow-up series. This series 
focuses specifically on Data Fabric uncore PMU support as the initial step.

Thanks,
Qi