[PATCH v3 4/4] arm_mpam: Update architecture version check for MPAM MSC

[Zeng Heng]

Hi all,

On 2026/5/9 0:35, Ben Horgan wrote:
> Hi James,
> 
> On 5/8/26 17:23, James Morse wrote:
>> From: Zeng Heng <zengheng4 at huawei.com>
>>
>> In addition to updating the CPU MPAM version check, the MPAM MSC version
>> check also need to be updated. mpam_msc_check_aidr() is added to check
>> the MSC AIDR register, ensuring that both the major and minor version
>> numbers fall within the supported range of the MPAM architecture version.
>>
>> Signed-off-by: Zeng Heng <zengheng4 at huawei.com>
>> [ morse: changed mpam_msc_check_aidr() to accept versions like v1.2 ]
>> Signed-off-by: James Morse <james.morse at arm.com>
>> ---
>>   drivers/resctrl/mpam_devices.c | 23 ++++++++++++++++++++---
>>   1 file changed, 20 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
>> index 916d8fd45ed5..1771e9712ca2 100644
>> --- a/drivers/resctrl/mpam_devices.c
>> +++ b/drivers/resctrl/mpam_devices.c
>> @@ -224,6 +224,24 @@ static inline void _mpam_write_monsel_reg(struct mpam_msc *msc, u16 reg, u32 val
>>   
>>   #define mpam_write_monsel_reg(msc, reg, val)   _mpam_write_monsel_reg(msc, MSMON_##reg, val)
>>   
>> +static bool mpam_msc_check_aidr(struct mpam_msc *msc)
>> +{
>> +	u32 aidr = __mpam_read_reg(msc, MPAMF_AIDR);
>> +	u32 major = FIELD_GET(MPAMF_AIDR_ARCH_MAJOR_REV, aidr);
>> +	u32 minor = FIELD_GET(MPAMF_AIDR_ARCH_MINOR_REV, aidr);
>> +
>> +	/*
>> +	 * v0.0 and >v2.x aren't supported, but anything else should be backward
>> +	 * compatible to v0.1 or v1.0.
>> +	 */
>> +	if (!major && !minor)
>> +		return false;
>> +	if (major > 1) >> +		return false;

Would it make sense to introduce a new macro that defines the maximum
supported major version?

~~~
#define MPAM_ARCH_MAJOR_VERSION_MAX    0x1

if (major > MPAM_ARCH_MAJOR_VERSION_MAX)
	return false;
~~~


Best regards,
Zeng Heng

>> +
>> +	return true;
>> +}
>> +
>>   static u64 mpam_msc_read_idr(struct mpam_msc *msc)
>>   {
>>   	u64 idr_high = 0, idr_low;
>> @@ -951,9 +969,8 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
>>   
>>   	lockdep_assert_held(&msc->probe_lock);
>>   
>> -	idr = __mpam_read_reg(msc, MPAMF_AIDR);
>> -	if ((idr & MPAMF_AIDR_ARCH_MAJOR_REV) != MPAM_ARCHITECTURE_V1) { >
> nit: MPAM_ARCHITECTURE_V1 is now unused.
> 
> Reviewed-by: Ben Horgan <ben.horgan at arm.com>
>