Hi Reinette,
On 10/15/2024 10:23 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 10/9/24 10:39 AM, Babu Moger wrote:
>> The ABMC feature provides an option to the user to assign a hardware
>> counter to an RMID, event pair and monitor the bandwidth as long as it is
>> assigned. The assigned RMID will be tracked by the hardware until the user
>> unassigns it manually.
>>
>> Counters are configured by writing to L3_QOS_ABMC_CFG MSR and
>> specifying the counter id, bandwidth source, and bandwidth types.
>>
>> Provide the interface to assign the counter ids to RMID.
>>
>> The feature details are documented in the 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).
>>
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>
> ...
>
>> ---
>> arch/x86/kernel/cpu/resctrl/internal.h | 3 ++
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 45 ++++++++++++++++++++++++++
>> 2 files changed, 48 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 58298db9034f..6d4df0490186 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -705,6 +705,9 @@ int mbm_cntr_alloc(struct rdt_resource *r);
>> void mbm_cntr_free(struct rdt_resource *r, u32 cntr_id);
>> void arch_mbm_evt_config_init(struct rdt_hw_mon_domain *hw_dom);
>> unsigned int mon_event_config_index_get(u32 evtid);
>> +int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
>> + enum resctrl_event_id evtid, u32 rmid, u32 closid,
>> + u32 cntr_id, bool assign);
>> 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/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 03b670b95c49..4ab1a18010c9 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -1853,6 +1853,51 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
>> return ret ?: nbytes;
>> }
>>
>> +static void resctrl_abmc_config_one_amd(void *info)
>> +{
>> + u64 *msrval = info;
>> +
>> + wrmsrl(MSR_IA32_L3_QOS_ABMC_CFG, *msrval);
>> +}
>> +
>> +/*
>> + * Send an IPI to the domain to assign the counter to RMID, event pair.
>> + */
>> +int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
>> + enum resctrl_event_id evtid, u32 rmid, u32 closid,
>> + u32 cntr_id, bool assign)
>> +{
>> + struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d);
>> + union l3_qos_abmc_cfg abmc_cfg = { 0 };
>> + struct arch_mbm_state *arch_mbm;
>> +
>> + abmc_cfg.split.cfg_en = 1;
>> + abmc_cfg.split.cntr_en = assign ? 1 : 0;
>> + abmc_cfg.split.cntr_id = cntr_id;
>> + abmc_cfg.split.bw_src = rmid;
>> +
>> + /* Update the event configuration from the domain */
>> + if (evtid == QOS_L3_MBM_TOTAL_EVENT_ID) {
>> + abmc_cfg.split.bw_type = hw_dom->mbm_total_cfg;
>> + arch_mbm = &hw_dom->arch_mbm_total[rmid];
>> + } else {
>> + abmc_cfg.split.bw_type = hw_dom->mbm_local_cfg;
>> + arch_mbm = &hw_dom->arch_mbm_local[rmid];
>> + }
>> +
>> + smp_call_function_any(&d->hdr.cpu_mask, resctrl_abmc_config_one_amd,
>> + &abmc_cfg, 1);
>> +
>> + /*
>> + * Reset the architectural state so that reading of hardware
>> + * counter is not considered as an overflow in next update.
>> + */
>> + if (arch_mbm)
>> + memset(arch_mbm, 0, sizeof(struct arch_mbm_state));
>> +
>
> More on this later, but I do believe later code can be simplified if
> reset of architectural state is done by caller. This function should
> focus on just configuring the counter.
Yes. It can be done by the caller. Need to introduce arch handler to do
this as it accesses the arch state.
>
>> + return 0;
>> +}
>> +
>> /* rdtgroup information files for one cache resource. */
>> static struct rftype res_common_files[] = {
>> {
>
> Reinette
>
--
- Babu Moger