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 2300FC83F17 for ; Mon, 28 Jul 2025 12:04:28 +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=Iqws1JtPL6lVP48gGMJgnPgXj5dZ3zmRQ3L+l3YE4f8=; b=mjTmtnTtmyAs6+dgA1FsytH+ug LZnx8KqILbyKXBUwA5IZL2Q05YyzcM2BFOmeQDh7pvJxFeaTiSSlXEELX6nqKQTbCkndrHPMb3ZaH AucwsLWtgc4Ox/zbhAQNCveQQPjaKRHkqMsWSbMk20baHG4tmgkaP1t6vVWzl/6ovuisbsDlTGctF QDxbrM4FGfBkbCzu3QPLXHYWOLhe3qtMcJvy1MV0eVTEJH4WyC7smkoNuxnk6IBUOq1SSWxakkC2d 3WBsT3/7E4r2EQwWpaR4KoWajTtvCwrkj7MShDsLcIl02XpdnpjoLeTE8vx3PYVd6d1yiOrjHQIEC jGOTn/EA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ugMab-0000000EOTW-3LwA; Mon, 28 Jul 2025 12:04:21 +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 1ugMVj-0000000ENv8-10DW for linux-arm-kernel@lists.infradead.org; Mon, 28 Jul 2025 11:59:20 +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 468E9152B; Mon, 28 Jul 2025 04:59:10 -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 55D4F3F673; Mon, 28 Jul 2025 04:59:14 -0700 (PDT) Message-ID: <7ab40c09-3922-4e0c-85dd-00ff05be4ce6@arm.com> Date: Mon, 28 Jul 2025 12:59:12 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 27/36] arm_mpam: Allow configuration to be applied and restored during cpu online 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> <20250711183648.30766-28-james.morse@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20250711183648.30766-28-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-20250728_045919_366492_BF3A9EDE X-CRM114-Status: GOOD ( 32.19 ) 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: > When CPUs come online the original configuration should be restored. > Once the maximum partid is known, allocate an configuration array for > each component, and reprogram each RIS configuration from this. > > The MPAM spec describes how multiple controls can interact. To prevent > this happening by accident, always reset controls that don't have a > valid configuration. This allows the same helper to be used for > configuration and reset. > > CC: Dave Martin > Signed-off-by: James Morse > --- > drivers/platform/arm64/mpam/mpam_devices.c | 236 ++++++++++++++++++-- > drivers/platform/arm64/mpam/mpam_internal.h | 26 ++- > 2 files changed, 234 insertions(+), 28 deletions(-) > > diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c > index bb3695eb84e9..f3ecfda265d2 100644 > --- a/drivers/platform/arm64/mpam/mpam_devices.c > +++ b/drivers/platform/arm64/mpam/mpam_devices.c > @@ -374,12 +374,16 @@ static void mpam_class_destroy(struct mpam_class *class) > add_to_garbage(class); > } > > +static void __destroy_component_cfg(struct mpam_component *comp); > + > static void mpam_comp_destroy(struct mpam_component *comp) > { > struct mpam_class *class = comp->class; > > lockdep_assert_held(&mpam_list_lock); > > + __destroy_component_cfg(comp); > + > list_del_rcu(&comp->class_list); > add_to_garbage(comp); > > @@ -909,51 +913,90 @@ static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd) > __mpam_write_reg(msc, reg, bm); > } > > -static void mpam_reset_ris_partid(struct mpam_msc_ris *ris, u16 partid) > +/* Called via IPI. Call while holding an SRCU reference */ > +static void mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid, > + struct mpam_config *cfg) > { > u16 bwa_fract = MPAMCFG_MBW_MAX_MAX; > struct mpam_msc *msc = ris->vmsc->msc; > struct mpam_props *rprops = &ris->props; > > - mpam_assert_srcu_read_lock_held(); > - > mutex_lock(&msc->part_sel_lock); > __mpam_part_sel(ris->ris_idx, partid, msc); > > - if (mpam_has_feature(mpam_feat_cpor_part, rprops)) > - mpam_reset_msc_bitmap(msc, MPAMCFG_CPBM, rprops->cpbm_wd); > + if (mpam_has_feature(mpam_feat_cpor_part, rprops)) { > + if (mpam_has_feature(mpam_feat_cpor_part, cfg)) > + mpam_write_partsel_reg(msc, CPBM, cfg->cpbm); > + else > + mpam_reset_msc_bitmap(msc, MPAMCFG_CPBM, > + rprops->cpbm_wd); > + } > > - if (mpam_has_feature(mpam_feat_mbw_part, rprops)) > - mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM, rprops->mbw_pbm_bits); > + if (mpam_has_feature(mpam_feat_mbw_part, rprops)) { > + if (mpam_has_feature(mpam_feat_mbw_part, cfg)) > + mpam_write_partsel_reg(msc, MBW_PBM, cfg->mbw_pbm); > + else > + mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM, > + rprops->mbw_pbm_bits); > + } > > if (mpam_has_feature(mpam_feat_mbw_min, rprops)) > mpam_write_partsel_reg(msc, MBW_MIN, 0); > > - if (mpam_has_feature(mpam_feat_mbw_max, rprops)) > - mpam_write_partsel_reg(msc, MBW_MAX, bwa_fract); > + if (mpam_has_feature(mpam_feat_mbw_max, rprops)) { > + if (mpam_has_feature(mpam_feat_mbw_max, cfg)) > + mpam_write_partsel_reg(msc, MBW_MAX, cfg->mbw_max); > + else > + mpam_write_partsel_reg(msc, MBW_MAX, bwa_fract); > + } > > if (mpam_has_feature(mpam_feat_mbw_prop, rprops)) > mpam_write_partsel_reg(msc, MBW_PROP, bwa_fract); > mutex_unlock(&msc->part_sel_lock); > } > > +struct reprogram_ris { > + struct mpam_msc_ris *ris; > + struct mpam_config *cfg; > +}; > + > +/* Call with MSC lock held */ > +static int mpam_reprogram_ris(void *_arg) > +{ > + u16 partid, partid_max; > + struct reprogram_ris *arg = _arg; > + struct mpam_msc_ris *ris = arg->ris; > + struct mpam_config *cfg = arg->cfg; > + > + if (ris->in_reset_state) > + return 0; > + > + spin_lock(&partid_max_lock); > + partid_max = mpam_partid_max; > + spin_unlock(&partid_max_lock); > + for (partid = 0; partid <= partid_max; partid++) > + mpam_reprogram_ris_partid(ris, partid, cfg); > + > + return 0; > +} > + > /* > * Called via smp_call_on_cpu() to prevent migration, while still being > * pre-emptible. > */ > static int mpam_reset_ris(void *arg) > { > - u16 partid, partid_max; > struct mpam_msc_ris *ris = arg; > + struct reprogram_ris reprogram_arg; > + struct mpam_config empty_cfg = { 0 }; > > if (ris->in_reset_state) > return 0; > > - spin_lock(&partid_max_lock); > - partid_max = mpam_partid_max; > - spin_unlock(&partid_max_lock); > - for (partid = 0; partid < partid_max; partid++) > - mpam_reset_ris_partid(ris, partid); > + reprogram_arg.ris = ris; > + reprogram_arg.cfg = &empty_cfg; > + > + mpam_reprogram_ris(&reprogram_arg); > > return 0; > } > @@ -984,13 +1027,11 @@ static int mpam_touch_msc(struct mpam_msc *msc, int (*fn)(void *a), void *arg) > > static void mpam_reset_msc(struct mpam_msc *msc, bool online) > { > - int idx; > struct mpam_msc_ris *ris; > > mpam_assert_srcu_read_lock_held(); > > mpam_mon_sel_outer_lock(msc); > - idx = srcu_read_lock(&mpam_srcu); > list_for_each_entry_srcu(ris, &msc->ris, msc_list, srcu_read_lock_held(&mpam_srcu)) { > mpam_touch_msc(msc, &mpam_reset_ris, ris); > > @@ -1000,10 +1041,38 @@ static void mpam_reset_msc(struct mpam_msc *msc, bool online) > */ > ris->in_reset_state = online; > } > - srcu_read_unlock(&mpam_srcu, idx); > mpam_mon_sel_outer_unlock(msc); > } > > +static void mpam_reprogram_msc(struct mpam_msc *msc) > +{ > + int idx; > + u16 partid; > + bool reset; > + struct mpam_config *cfg; > + struct mpam_msc_ris *ris; > + > + idx = srcu_read_lock(&mpam_srcu); > + list_for_each_entry_rcu(ris, &msc->ris, msc_list) { > + if (!mpam_is_enabled() && !ris->in_reset_state) { > + mpam_touch_msc(msc, &mpam_reset_ris, ris); > + ris->in_reset_state = true; > + continue; > + } > + > + reset = true; > + for (partid = 0; partid <= mpam_partid_max; partid++) { Do we need to consider 'partid_max_lock' here? > + cfg = &ris->vmsc->comp->cfg[partid]; > + if (cfg->features) > + reset = false; > + > + mpam_reprogram_ris_partid(ris, partid, cfg); > + } > + ris->in_reset_state = reset; > + } > + srcu_read_unlock(&mpam_srcu, idx); > +} > + > static void _enable_percpu_irq(void *_irq) > { > int *irq = _irq; > @@ -1025,7 +1094,7 @@ static int mpam_cpu_online(unsigned int cpu) > _enable_percpu_irq(&msc->reenable_error_ppi); > > if (atomic_fetch_inc(&msc->online_refs) == 0) > - mpam_reset_msc(msc, true); > + mpam_reprogram_msc(msc); > } > srcu_read_unlock(&mpam_srcu, idx); > > @@ -1806,6 +1875,43 @@ static void mpam_unregister_irqs(void) > cpus_read_unlock(); > } > > +static void __destroy_component_cfg(struct mpam_component *comp) > +{ > + add_to_garbage(comp->cfg); > +} > + > +static int __allocate_component_cfg(struct mpam_component *comp) > +{ > + if (comp->cfg) > + return 0; > + > + comp->cfg = kcalloc(mpam_partid_max + 1, sizeof(*comp->cfg), GFP_KERNEL); And here? > + if (!comp->cfg) > + return -ENOMEM; > + init_garbage(comp->cfg); > + > + return 0; > +} > + > +static int mpam_allocate_config(void) > +{ > + int err = 0; > + struct mpam_class *class; > + struct mpam_component *comp; > + > + lockdep_assert_held(&mpam_list_lock); > + > + list_for_each_entry(class, &mpam_classes, classes_list) { > + list_for_each_entry(comp, &class->components, class_list) { > + err = __allocate_component_cfg(comp); > + if (err) > + return err; > + } > + } > + > + return 0; > +} > + > static void mpam_enable_once(void) > { > int err; > @@ -1817,12 +1923,21 @@ static void mpam_enable_once(void) > */ > cpus_read_lock(); > mutex_lock(&mpam_list_lock); > - mpam_enable_merge_features(&mpam_classes); > + do { > + mpam_enable_merge_features(&mpam_classes); > > - err = mpam_register_irqs(); > - if (err) > - pr_warn("Failed to register irqs: %d\n", err); > + err = mpam_allocate_config(); > + if (err) { > + pr_err("Failed to allocate configuration arrays.\n"); > + break; > + } > > + err = mpam_register_irqs(); > + if (err) { > + pr_warn("Failed to register irqs: %d\n", err); > + break; > + } > + } while (0); > mutex_unlock(&mpam_list_lock); > cpus_read_unlock(); > > @@ -1861,6 +1976,8 @@ static void mpam_reset_component_locked(struct mpam_component *comp) > might_sleep(); > lockdep_assert_cpus_held(); > > + memset(comp->cfg, 0, (mpam_partid_max * sizeof(*comp->cfg))); And here? > + > idx = srcu_read_lock(&mpam_srcu); > list_for_each_entry_rcu(vmsc, &comp->vmsc, comp_list) { > msc = vmsc->msc; > @@ -1963,6 +2080,79 @@ void mpam_enable(struct work_struct *work) > mpam_enable_once(); > } > > +struct mpam_write_config_arg { > + struct mpam_msc_ris *ris; > + struct mpam_component *comp; > + u16 partid; > +}; > + > +static int __write_config(void *arg) > +{ > + struct mpam_write_config_arg *c = arg; > + > + mpam_reprogram_ris_partid(c->ris, c->partid, &c->comp->cfg[c->partid]); > + > + return 0; > +} > + > +#define maybe_update_config(cfg, feature, newcfg, member, changes) do { \ > + if (mpam_has_feature(feature, newcfg) && \ > + (newcfg)->member != (cfg)->member) { \ > + (cfg)->member = (newcfg)->member; \ > + cfg->features |= (1 << feature); \ > + \ > + (changes) |= (1 << feature); \ > + } \ > +} while (0) > + > +static mpam_features_t mpam_update_config(struct mpam_config *cfg, > + const struct mpam_config *newcfg) > +{ > + mpam_features_t changes = 0; > + > + maybe_update_config(cfg, mpam_feat_cpor_part, newcfg, cpbm, changes); > + maybe_update_config(cfg, mpam_feat_mbw_part, newcfg, mbw_pbm, changes); > + maybe_update_config(cfg, mpam_feat_mbw_max, newcfg, mbw_max, changes); > + > + return changes; > +} > + > +/* TODO: split into write_config/sync_config */ > +/* TODO: add config_dirty bitmap to drive sync_config */ > +int mpam_apply_config(struct mpam_component *comp, u16 partid, > + struct mpam_config *cfg) > +{ > + struct mpam_write_config_arg arg; > + struct mpam_msc_ris *ris; > + struct mpam_vmsc *vmsc; > + struct mpam_msc *msc; > + int idx; > + > + lockdep_assert_cpus_held(); > + > + /* Don't pass in the current config! */ > + WARN_ON_ONCE(&comp->cfg[partid] == cfg); > + > + if (!mpam_update_config(&comp->cfg[partid], cfg)) > + return 0; > + > + arg.comp = comp; > + arg.partid = partid; > + > + idx = srcu_read_lock(&mpam_srcu); > + list_for_each_entry_rcu(vmsc, &comp->vmsc, comp_list) { > + msc = vmsc->msc; > + > + list_for_each_entry_rcu(ris, &vmsc->ris, vmsc_list) { > + arg.ris = ris; > + mpam_touch_msc(msc, __write_config, &arg); > + } > + } > + srcu_read_unlock(&mpam_srcu, idx); > + > + return 0; > +} > + > /* > * MSC that are hidden under caches are not created as platform devices > * as there is no cache driver. Caches are also special-cased in > diff --git a/drivers/platform/arm64/mpam/mpam_internal.h b/drivers/platform/arm64/mpam/mpam_internal.h > index 1a24424b48df..029ec89f56f2 100644 > --- a/drivers/platform/arm64/mpam/mpam_internal.h > +++ b/drivers/platform/arm64/mpam/mpam_internal.h > @@ -190,11 +190,7 @@ struct mpam_props { > u16 num_mbwu_mon; > }; > > -static inline bool mpam_has_feature(enum mpam_device_features feat, > - struct mpam_props *props) > -{ > - return (1 << feat) & props->features; > -} > +#define mpam_has_feature(_feat, x) ((1 << (_feat)) & (x)->features) > > static inline void mpam_set_feature(enum mpam_device_features feat, > struct mpam_props *props) > @@ -225,6 +221,17 @@ struct mpam_class { > struct mpam_garbage garbage; > }; > > +struct mpam_config { > + /* Which configuration values are valid. 0 is used for reset */ > + mpam_features_t features; > + > + u32 cpbm; > + u32 mbw_pbm; > + u16 mbw_max; > + > + struct mpam_garbage garbage; > +}; > + > struct mpam_component { > u32 comp_id; > > @@ -233,6 +240,12 @@ struct mpam_component { > > cpumask_t affinity; > > + /* > + * Array of configuration values, indexed by partid. > + * Read from cpuhp callbacks, hold the cpuhp lock when writing. > + */ > + struct mpam_config *cfg; > + > /* member of mpam_class:components */ > struct list_head class_list; > > @@ -297,6 +310,9 @@ extern u8 mpam_pmg_max; > void mpam_enable(struct work_struct *work); > void mpam_disable(struct work_struct *work); > > +int mpam_apply_config(struct mpam_component *comp, u16 partid, > + struct mpam_config *cfg); > + > int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level, > cpumask_t *affinity); > -- Thanks, Ben