Re: [PATCH v4 11/19] x86/resctrl: Introduce mbm_total_cfg and mbm_local_cfg

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Hi Reinette,

On 6/13/24 20:43, Reinette Chatre wrote:
> Hi Babu,
> 
> On 5/24/24 5:23 AM, Babu Moger wrote:
>> If the BMEC (Bandwidth Monitoring Event Configuration) feature is
>> supported, the bandwidth events can be configured to track specific
>> events. The event configuration is domain specific. ABMC (Assignable
>> Bandwidth Monitoring Counters) feature needs event configuration
>> information to assign hardware counter to an RMID. Event configurations
>> are not stored in resctrl but instead always read from or written to
>> hardware directly when prompted by user space.
>>
>> Read the event configuration from the hardware during the domain
>> initialization. Save the configuration information in the rdt_hw_domain,
>> so it can be used for counter assignment.
>>
>> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
>> ---
>> v4: Read the configuration information from the hardware to initialize.
>>      Added few commit messages.
>>      Fixed the tab spaces.
>>
>> v3: Minor changes related to rebase in mbm_config_write_domain.
>>
>> v2: No changes.
>> ---
>>   arch/x86/kernel/cpu/resctrl/core.c     |  2 ++
>>   arch/x86/kernel/cpu/resctrl/internal.h |  5 +++++
>>   arch/x86/kernel/cpu/resctrl/monitor.c  | 21 +++++++++++++++++++++
>>   3 files changed, 28 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c
>> b/arch/x86/kernel/cpu/resctrl/core.c
>> index ec93f6a50308..856c46d12177 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -542,6 +542,8 @@ static void domain_add_cpu(int cpu, struct
>> rdt_resource *r)
>>           return;
>>       }
>>   +    arch_domain_mbm_evt_config(hw_dom);
>> +
>>       list_add_tail_rcu(&d->list, add_pos);
>>         err = resctrl_online_domain(r, d);
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h
>> b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 5e7e76cd512f..60a1ca0a11a7 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -373,6 +373,8 @@ struct arch_mbm_state {
>>    * @ctrl_val:    array of cache or mem ctrl values (indexed by CLOSID)
>>    * @arch_mbm_total:    arch private state for MBM total bandwidth
>>    * @arch_mbm_local:    arch private state for MBM local bandwidth
>> + * @mbm_total_cfg:    MBM total bandwidth configuration
>> + * @mbm_local_cfg:    MBM local bandwidth configuration
>>    *
>>    * Members of this structure are accessed via helpers that provide
>> abstraction.
>>    */
>> @@ -381,6 +383,8 @@ struct rdt_hw_domain {
>>       u32                *ctrl_val;
>>       struct arch_mbm_state        *arch_mbm_total;
>>       struct arch_mbm_state        *arch_mbm_local;
>> +    u32                mbm_total_cfg;
>> +    u32                mbm_local_cfg;
>>   };
> 
> Similar to the abmc_enabled member of rdt_hw_resource, these new
> members of rdt_hw_domain are architecture specific and should never be
> touched directly by resctrl fs code, for example, from mbm_config_show().

Yes. Understood. Will check all the accesses.

> 
>>     static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct
>> rdt_domain *r)
>> @@ -622,6 +626,7 @@ void __check_limbo(struct rdt_domain *d, bool
>> force_free);
>>   void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
>>   void __init resctrl_file_fflags_init(const char *config,
>>                        unsigned long fflags);
>> +void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom);
>>   void rdt_staged_configs_clear(void);
>>   bool closid_allocated(unsigned int closid);
>>   int resctrl_find_cleanest_closid(void);
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c
>> b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index b1d002e5e93d..ab0f4bb49bd9 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -1093,6 +1093,27 @@ int __init rdt_get_mon_l3_config(struct
>> rdt_resource *r)
>>       return 0;
>>   }
>>   +void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom)
>> +{
>> +    u64 msrval;
>> +
>> +    /*
>> +     * Read the configuration registers QOS_EVT_CFG_n, where <n> is
>> +     * the BMEC event number (EvtID).
>> +     * 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
>> +     * 1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
> 
> This is what mon_event_config_index_get() is for, no?

Yes, it is. I can change it.

> 
>> +     */
>> +    if (mbm_total_event.configurable) {
>> +        rdmsrl(MSR_IA32_EVT_CFG_BASE, msrval);
>> +        hw_dom->mbm_total_cfg = msrval & MAX_EVT_CONFIG_BITS;
>> +    }
>> +
>> +    if (mbm_local_event.configurable) {
>> +        rdmsrl(MSR_IA32_EVT_CFG_BASE + 1, msrval);
>> +        hw_dom->mbm_local_cfg = msrval & MAX_EVT_CONFIG_BITS;
>> +    }
>> +}
>> +
>>   void __exit rdt_put_mon_l3_config(void)
>>   {
>>       dom_data_exit();
> 
> Reinette
> 

-- 
Thanks
Babu Moger




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