linux-kernel - Re: [PATCH v11 14/23] x86/resctrl: Implement resctrl_arch_config

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Message-ID: <21666e6f-9886-4657-bc14-af472bc878c8@arm.com>
Date: Fri, 21 Feb 2025 18:06:18 +0000
From: James Morse <james.morse@....com>
To: Babu Moger <babu.moger@....com>, corbet@....net,
 reinette.chatre@...el.com, tglx@...utronix.de, mingo@...hat.com,
 bp@...en8.de, dave.hansen@...ux.intel.com, tony.luck@...el.com,
 peternewman@...gle.com
Cc: fenghua.yu@...el.com, x86@...nel.org, hpa@...or.com, paulmck@...nel.org,
 akpm@...ux-foundation.org, thuth@...hat.com, rostedt@...dmis.org,
 xiongwei.song@...driver.com, pawan.kumar.gupta@...ux.intel.com,
 daniel.sneddon@...ux.intel.com, jpoimboe@...nel.org, perry.yuan@....com,
 sandipan.das@....com, kai.huang@...el.com, xiaoyao.li@...el.com,
 seanjc@...gle.com, xin3.li@...el.com, andrew.cooper3@...rix.com,
 ebiggers@...gle.com, mario.limonciello@....com, tan.shaopeng@...itsu.com,
 linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
 maciej.wieczor-retman@...el.com, eranian@...gle.com
Subject: Re: [PATCH v11 14/23] x86/resctrl: Implement
 resctrl_arch_config_cntr() to assign a counter with ABMC

Hi Babu,

On 22/01/2025 20:20, 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.
> 
> Implement an architecture-specific handler to assign and unassign the
> counter. Configure counters by writing to the L3_QOS_ABMC_CFG MSR,
> specifying the counter ID, bandwidth source (RMID), and event
> configuration.
> 
> 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).

> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index acac7972cea4..161d3feb567c 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -724,4 +724,7 @@ unsigned int mon_event_config_index_get(u32 evtid);
>  void resctrl_arch_mon_event_config_set(void *info);
>  u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
>  				      enum resctrl_event_id eventid);
> +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);
>  #endif /* _ASM_X86_RESCTRL_INTERNAL_H */


Could this be added to include/linux/resctrl.h instead? Its where it needs to end up
eventually.


Thanks,

James