From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 41991C87FCA for ; Thu, 24 Jul 2025 17:05:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TMUfxu+RXOXtNJ0RQLJbLGemygho7LiDc9AzkkOqJ5c=; b=nlOyOmFuHqRLnzsefBwp0lyB// Xhii5GRUhh5UhoOUg9U/kd7FBsuRDrWNMrE6oPbHQtqjAB8NW+0tRzxameAPnqnRDZogPDhBaUZ0y 4hY3su3RmjiWbI0ytcOqqRU7ZVaCAyvn0S9szAkGHwKz24ywPemBP32QvURIpyRD01+0keJ6SfFJ4 cfq0n+gE9zof8cba2JPSR9Z64Prx2t5Ls0WIkDvQhexdY0G7p59mPviQaTtb/hL5WtqVo8ulsm+L1 tkaX5d2jOk6Pq2nSvqZvf6w2TG2eYrqqYQkO8xVJfs3Amzr5Vzg3Xau3FLQx3+bQQo/uwJLy45MP0 zaGng6fw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uezNx-000000083dp-3qGd; Thu, 24 Jul 2025 17:05:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uexYK-00000007oe7-2Al7 for linux-arm-kernel@lists.infradead.org; Thu, 24 Jul 2025 15:08:14 +0000 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250724_080812_648200_991C70E6 X-CRM114-Status: GOOD ( 32.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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