Hi James,
On 2/20/24 11:56, James Morse wrote:
> Hi Babu,
>
> On 19/01/2024 18:22, Babu Moger wrote:
>> ABMC feature details are reported via CPUID Fn8000_0020_EBX_x5.
>> Bits Description
>> 15:0 MAX_ABMC Maximum Supported Assignable Bandwidth
>> Monitoring Counter ID + 1
>>
>> Detect the feature details and update
>> /sys/fs/resctrl/info/L3_MON/mon_features.
>>
>> If the system supports Assignable Bandwidth Monitoring Counters (ABMC),
>> the output will have additional text.
>> $ cat /sys/fs/resctrl/info/L3_MON/mon_features
>> mbm_assign_capable
>>
>> The feature details are documented in APM listed below [1].
>> [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
>> Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
>> Monitoring (ABMC).
>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 4efe2d6a9eb7..f40ee271a5c7 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -303,6 +303,17 @@ static void rdt_get_cdp_l2_config(void)
>> rdt_get_cdp_config(RDT_RESOURCE_L2);
>> }
>>
>> +static void rdt_get_abmc_cfg(struct rdt_resource *r)
>> +{
>> + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>> + u32 eax, ebx, ecx, edx;
>> +
>> + r->mbm_assign_capable = true;
>> + /* Query CPUID_Fn80000020_EBX_x05 for number of ABMC counters */
>> + cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
>
>> + hw_res->mbm_assignable_counters = (ebx & 0xFFFF) + 1;
>
> Please put the mbm_assignable_counters field in struct rdt_resource. The filesystem code
> needs to access this to allocate/free counters and report how many are available.
> After all this gets split and the filesystem code moves to /fs/, the rdt_hw_resrouce
> structure is inaccessible to the filesystem code.
Ok. Sure.
>
>
>> +}
>> +
>> static void
>> mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
>> {
>> @@ -815,6 +826,12 @@ static __init bool get_rdt_alloc_resources(void)
>> if (get_slow_mem_config())
>> ret = true;
>>
>> + if (rdt_cpu_has(X86_FEATURE_ABMC)) {
>> + r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
>> + rdt_get_abmc_cfg(r);
>
>> + ret = true;
>
> Does it make sense to report rdt_alloc_capable if the SoC has ABMC, but nothing that can
> be configured?
Good catch. Will move it to get_rdt_mon_resources().
>
> This code would probably make more sense in the get_rdt_mon_resources().
Sure.
>
>
>> + }
>> +
>> return ret;
>> }
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index a4f1aa15f0a2..01eb0522b42b 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -391,6 +391,8 @@ struct rdt_parse_data {
>> * resctrl_arch_get_num_closid() to avoid confusion
>> * with struct resctrl_schema's property of the same name,
>> * which has been corrected for features like CDP.
>
>> + * @mbm_assignable_counters:
>> + * Maximum number of assignable ABMC counters
>
> As above, please move this to struct rdt_resource. The 'hw' version becomes private to the
> arch code after the move to /fs//
>
>
>> * @msr_base: Base MSR address for CBMs
>> * @msr_update: Function pointer to update QOS MSRs
>> * @mon_scale: cqm counter * mon_scale = occupancy in bytes
>
>
> Thanks,
>
> James
>
--
Thanks
Babu Moger
