From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B0ABC2E973A for ; Thu, 24 Jul 2025 15:08:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753369693; cv=none; b=NdHAslUArqP/uUgTMSYL067UDNeoR9lipTfIAVRek0RWXLQ31vaC7wNEt7NG64fDrHEnYSl02vG/2s0ytsxFdNZlgJRn4zX4dfO3+zJHxyIj5rB33G1vO10s/IPG9LU4ZnbP9aKmQN4lKio1FTt4A6RECcuQj/KiDLd6owpXiSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753369693; c=relaxed/simple; bh=hPs7kgn0sqUMrvPXcs+ygRaBmiQ6NUqhgNGpub5d/KI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=P8e0Z/oRvlgI8+3ze9M+SKZ93JIP7Lf7oZkwebPo8o5g8viRc+N5iiAYm0Ro8gNRDhQBC750z6RFnwK9fZegOauYn6dx/6jJuoaU8Ov2KMQxHsVIbM+mxY4VEvxnNi7Vpf8yuIyAC9v8EoF5Y4ePpVcx964Ahsprq0TUALfmAAU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2D1571A00; Thu, 24 Jul 2025 08:08:03 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4524E3F6A8; Thu, 24 Jul 2025 08:08:06 -0700 (PDT) Message-ID: Date: Thu, 24 Jul 2025 16:08:04 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 20/36] arm_mpam: Probe the hardware features resctrl supports To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Rob Herring , Rohit Mathew , Shanker Donthineni , Zeng Heng , Lecopzer Chen , Carl Worth , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Dave Martin , Koba Ko References: <20250711183648.30766-1-james.morse@arm.com> <20250711183648.30766-21-james.morse@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20250711183648.30766-21-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi James, On 7/11/25 19:36, James Morse wrote: > Expand the probing support with the control and monitor types > we can use with resctrl. > > CC: Dave Martin > Signed-off-by: James Morse > --- > drivers/platform/arm64/mpam/mpam_devices.c | 154 +++++++++++++++++++- > drivers/platform/arm64/mpam/mpam_internal.h | 53 +++++++ > 2 files changed, 206 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c > index 8646fb85ad09..61911831ab39 100644 > --- a/drivers/platform/arm64/mpam/mpam_devices.c > +++ b/drivers/platform/arm64/mpam/mpam_devices.c > @@ -102,7 +102,7 @@ static LLIST_HEAD(mpam_garbage); > > static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg) > { > - WARN_ON_ONCE(reg > msc->mapped_hwpage_sz); > + WARN_ON_ONCE(reg + sizeof(u32) > msc->mapped_hwpage_sz); > WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > > return readl_relaxed(msc->mapped_hwpage + reg); > @@ -131,6 +131,20 @@ static inline void _mpam_write_partsel_reg(struct mpam_msc *msc, u16 reg, u32 va > } > #define mpam_write_partsel_reg(msc, reg, val) _mpam_write_partsel_reg(msc, MPAMCFG_##reg, val) > > +static inline u32 _mpam_read_monsel_reg(struct mpam_msc *msc, u16 reg) > +{ > + mpam_mon_sel_lock_held(msc); > + return __mpam_read_reg(msc, reg); > +} > +#define mpam_read_monsel_reg(msc, reg) _mpam_read_monsel_reg(msc, MSMON_##reg) > + > +static inline void _mpam_write_monsel_reg(struct mpam_msc *msc, u16 reg, u32 val) > +{ > + mpam_mon_sel_lock_held(msc); > + __mpam_write_reg(msc, reg, val); > +} > +#define mpam_write_monsel_reg(msc, reg, val) _mpam_write_monsel_reg(msc, MSMON_##reg, val) > + > static u64 mpam_msc_read_idr(struct mpam_msc *msc) > { > u64 idr_high = 0, idr_low; > @@ -645,6 +659,137 @@ static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc, > return found; > } > > +/* > + * IHI009A.a has this nugget: "If a monitor does not support automatic behaviour > + * of NRDY, software can use this bit for any purpose" - so hardware might not > + * implement this - but it isn't RES0. > + * > + * Try and see what values stick in this bit. If we can write either value, > + * its probably not implemented by hardware. > + */ > +#define mpam_ris_hw_probe_hw_nrdy(_ris, _mon_reg, _result) \ > +do { \ > + u32 now; \ > + u64 mon_sel; \ > + bool can_set, can_clear; \ > + struct mpam_msc *_msc = _ris->vmsc->msc; \ > + \ > + if (WARN_ON_ONCE(!mpam_mon_sel_inner_lock(_msc))) { \ > + _result = false; \ > + break; \ > + } \ > + mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, 0) | \ > + FIELD_PREP(MSMON_CFG_MON_SEL_RIS, _ris->ris_idx); \ > + mpam_write_monsel_reg(_msc, CFG_MON_SEL, mon_sel); \ > + \ > + mpam_write_monsel_reg(_msc, _mon_reg, MSMON___NRDY); \ > + now = mpam_read_monsel_reg(_msc, _mon_reg); \ > + can_set = now & MSMON___NRDY; \ > + \ > + mpam_write_monsel_reg(_msc, _mon_reg, 0); \ > + now = mpam_read_monsel_reg(_msc, _mon_reg); \ > + can_clear = !(now & MSMON___NRDY); \ > + mpam_mon_sel_inner_unlock(_msc); \ > + \ > + _result = (!can_set || !can_clear); \ > +} while (0) It is a bit surprising that something that looks like a function modifies a boolean passed by value. Consider continuing the pattern you have above: #define mpam_ris_hw_probe_hw_nrdy(_ris, _mon_reg, _result) _mpam_ris_hw_probe_hw_nrdy(_ris, MSMON##_mon_reg, _result) with signature: void _mpam_ris_hw_probe_hw_nrdy(struct mpam_msc *msc, u16 reg, bool *hw_managed); and using the _mpam functions from the new _mpam_ris_hw_probe_hw_nrdy(). > + > +static void mpam_ris_hw_probe(struct mpam_msc_ris *ris) > +{ > + int err; > + struct mpam_msc *msc = ris->vmsc->msc; > + struct mpam_props *props = &ris->props; > + > + lockdep_assert_held(&msc->probe_lock); > + lockdep_assert_held(&msc->part_sel_lock); > + > + /* Cache Portion partitioning */ > + if (FIELD_GET(MPAMF_IDR_HAS_CPOR_PART, ris->idr)) { > + u32 cpor_features = mpam_read_partsel_reg(msc, CPOR_IDR); > + > + props->cpbm_wd = FIELD_GET(MPAMF_CPOR_IDR_CPBM_WD, cpor_features); > + if (props->cpbm_wd) > + mpam_set_feature(mpam_feat_cpor_part, props); > + } > + > + /* Memory bandwidth partitioning */ > + if (FIELD_GET(MPAMF_IDR_HAS_MBW_PART, ris->idr)) { > + u32 mbw_features = mpam_read_partsel_reg(msc, MBW_IDR); > + > + /* portion bitmap resolution */ > + props->mbw_pbm_bits = FIELD_GET(MPAMF_MBW_IDR_BWPBM_WD, mbw_features); > + if (props->mbw_pbm_bits && > + FIELD_GET(MPAMF_MBW_IDR_HAS_PBM, mbw_features)) > + mpam_set_feature(mpam_feat_mbw_part, props); > + > + props->bwa_wd = FIELD_GET(MPAMF_MBW_IDR_BWA_WD, mbw_features); > + if (props->bwa_wd && FIELD_GET(MPAMF_MBW_IDR_HAS_MAX, mbw_features)) > + mpam_set_feature(mpam_feat_mbw_max, props); > + } > + > + /* Performance Monitoring */ > + if (FIELD_GET(MPAMF_IDR_HAS_MSMON, ris->idr)) { > + u32 msmon_features = mpam_read_partsel_reg(msc, MSMON_IDR); > + > + /* > + * If the firmware max-nrdy-us property is missing, the > + * CSU counters can't be used. Should we wait forever? > + */ > + err = device_property_read_u32(&msc->pdev->dev, > + "arm,not-ready-us", > + &msc->nrdy_usec); > + > + if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_CSU, msmon_features)) { > + u32 csumonidr; > + > + csumonidr = mpam_read_partsel_reg(msc, CSUMON_IDR); > + props->num_csu_mon = FIELD_GET(MPAMF_CSUMON_IDR_NUM_MON, csumonidr); > + if (props->num_csu_mon) { > + bool hw_managed; > + > + mpam_set_feature(mpam_feat_msmon_csu, props); > + > + /* Is NRDY hardware managed? */ > + mpam_mon_sel_outer_lock(msc); > + mpam_ris_hw_probe_hw_nrdy(ris, CSU, hw_managed); > + mpam_mon_sel_outer_unlock(msc); > + if (hw_managed) > + mpam_set_feature(mpam_feat_msmon_csu_hw_nrdy, props); > + } > + > + /* > + * Accept the missing firmware property if NRDY appears > + * un-implemented. > + */ > + if (err && mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, props)) > + pr_err_once("Counters are not usable because not-ready timeout was not provided by firmware."); > + } > + if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_MBWU, msmon_features)) { > + bool hw_managed; > + u32 mbwumonidr = mpam_read_partsel_reg(msc, MBWUMON_IDR); > + > + props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumonidr); > + if (props->num_mbwu_mon) > + mpam_set_feature(mpam_feat_msmon_mbwu, props); > + > + if (FIELD_GET(MPAMF_MBWUMON_IDR_HAS_RWBW, mbwumonidr)) > + mpam_set_feature(mpam_feat_msmon_mbwu_rwbw, props); > + > + /* Is NRDY hardware managed? */ > + mpam_mon_sel_outer_lock(msc); > + mpam_ris_hw_probe_hw_nrdy(ris, MBWU, hw_managed); > + mpam_mon_sel_outer_unlock(msc); > + if (hw_managed) > + mpam_set_feature(mpam_feat_msmon_mbwu_hw_nrdy, props); > + > + /* > + * Don't warn about any missing firmware property for > + * MBWU NRDY - it doesn't make any sense! > + */ > + } > + } > +} > + > static int mpam_msc_hw_probe(struct mpam_msc *msc) > { > u64 idr; > @@ -665,6 +810,7 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) > > idr = mpam_msc_read_idr(msc); > mutex_unlock(&msc->part_sel_lock); > + > msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr); > > /* Use these values so partid/pmg always starts with a valid value */ > @@ -685,6 +831,12 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) > ris = mpam_get_or_create_ris(msc, ris_idx); > if (IS_ERR(ris)) > return PTR_ERR(ris); > + ris->idr = idr; > + > + mutex_lock(&msc->part_sel_lock); > + __mpam_part_sel(ris_idx, 0, msc); > + mpam_ris_hw_probe(ris); > + mutex_unlock(&msc->part_sel_lock); > } > > spin_lock(&partid_max_lock); > diff --git a/drivers/platform/arm64/mpam/mpam_internal.h b/drivers/platform/arm64/mpam/mpam_internal.h > index 42a454d5f914..ae6fd1f62cc4 100644 > --- a/drivers/platform/arm64/mpam/mpam_internal.h > +++ b/drivers/platform/arm64/mpam/mpam_internal.h > @@ -136,6 +136,55 @@ static inline void mpam_mon_sel_lock_held(struct mpam_msc *msc) > lockdep_assert_preemption_enabled(); > } > > +/* > + * When we compact the supported features, we don't care what they are. > + * Storing them as a bitmap makes life easy. > + */ > +typedef u16 mpam_features_t; > + > +/* Bits for mpam_features_t */ > +enum mpam_device_features { > + mpam_feat_ccap_part = 0, > + mpam_feat_cpor_part, > + mpam_feat_mbw_part, > + mpam_feat_mbw_min, > + mpam_feat_mbw_max, > + mpam_feat_mbw_prop, > + mpam_feat_msmon, > + mpam_feat_msmon_csu, > + mpam_feat_msmon_csu_capture, > + mpam_feat_msmon_csu_hw_nrdy, > + mpam_feat_msmon_mbwu, > + mpam_feat_msmon_mbwu_capture, > + mpam_feat_msmon_mbwu_rwbw, > + mpam_feat_msmon_mbwu_hw_nrdy, > + mpam_feat_msmon_capt, > + MPAM_FEATURE_LAST, > +}; > +#define MPAM_ALL_FEATURES ((1 << MPAM_FEATURE_LAST) - 1) > + > +struct mpam_props { > + mpam_features_t features; > + > + u16 cpbm_wd; > + u16 mbw_pbm_bits; > + u16 bwa_wd; > + u16 num_csu_mon; > + u16 num_mbwu_mon; > +}; > + > +static inline bool mpam_has_feature(enum mpam_device_features feat, > + struct mpam_props *props) > +{ > + return (1 << feat) & props->features; > +} > + > +static inline void mpam_set_feature(enum mpam_device_features feat, > + struct mpam_props *props) > +{ > + props->features |= (1 << feat); > +} > + > struct mpam_class { > /* mpam_components in this class */ > struct list_head components; > @@ -175,6 +224,8 @@ struct mpam_vmsc { > /* mpam_msc_ris in this vmsc */ > struct list_head ris; > > + struct mpam_props props; > + > /* All RIS in this vMSC are members of this MSC */ > struct mpam_msc *msc; > > @@ -186,6 +237,8 @@ struct mpam_vmsc { > > struct mpam_msc_ris { > u8 ris_idx; > + u64 idr; > + struct mpam_props props; > > cpumask_t affinity; > -- Thanks, Ben