From nobody Tue Feb 10 04:33:07 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C56323271EC; Fri, 7 Nov 2025 12:38:10 +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=1762519092; cv=none; b=kwsPeI6ln7GPWvOznOYnmNwwjqqINR5gFoxiy8sAIqb5Wjahpt+8cXq6vO4ZHT5k49gZsaHnIB6YUvExOdcHq0rgvs5NW4E0pX1B9uBq72VaBFG0kUD2YMOFSXdrClZJMw1TFZvzJlAG22sNSrwVDF1xXXSQwewXNBKfrc36YU0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762519092; c=relaxed/simple; bh=J05Up4NeCCqMQMzDQ3YdhYaXbu3zXuJAYeXHQysZbdY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=srP6jBFoqONwY9lQQrWQ5jqguUpx5BQDQ9RCMYxjwyPVTRaAAgFwlHWjoHVdSRERjncjtCl3ixV6CQLIq/c/0pdboKzuGAsBYjqBwTNuZdFHJUv9E9BT0gfJUF1jzcztYh35pGaj9w/bx8oA5pr2YpB73cD+tjPEuUnrsrtDMwY= 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 AB0471515; Fri, 7 Nov 2025 04:38:02 -0800 (PST) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8640E3F66E; Fri, 7 Nov 2025 04:38:05 -0800 (PST) From: Ben Horgan To: james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, Fenghua Yu , Ben Horgan Subject: [PATCH 31/33] arm_mpam: Add helper to reset saved mbwu state Date: Fri, 7 Nov 2025 12:34:48 +0000 Message-ID: <20251107123450.664001-32-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251107123450.664001-1-ben.horgan@arm.com> References: <20251107123450.664001-1-ben.horgan@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: James Morse resctrl expects to reset the bandwidth counters when the filesystem is mounted. To allow this, add a helper that clears the saved mbwu state. Instead of cross calling to each CPU that can access the component MSC to write to the counter, set a flag that causes it to be zero'd on the the next read. This is easily done by forcing a configuration update. Signed-off-by: James Morse Reviewed-by: Fenghua Yu Tested-by: Fenghua Yu Cc: Peter Newman Signed-off-by: Ben Horgan Reviewed-by: Gavin Shan Reviewed-by: Jonathan Cameron --- Changes since v3: Correct type checking, use mpam_feat_msmon_mbwu_counter --- drivers/resctrl/mpam_devices.c | 48 ++++++++++++++++++++++++++++++++- drivers/resctrl/mpam_internal.h | 2 ++ 2 files changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 59d12ee1195d..eb6417f57e23 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -1075,6 +1075,7 @@ static void __ris_msmon_read(void *arg) bool overflow; struct mon_read *m =3D arg; struct mon_cfg *ctx =3D m->ctx; + bool reset_on_next_read =3D false; struct mpam_msc_ris *ris =3D m->ris; struct msmon_mbwu_state *mbwu_state; struct mpam_props *rprops =3D &ris->props; @@ -1089,6 +1090,20 @@ static void __ris_msmon_read(void *arg) FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx); mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel); =20 + switch (m->type) { + case mpam_feat_msmon_mbwu_31counter: + case mpam_feat_msmon_mbwu_44counter: + case mpam_feat_msmon_mbwu_63counter: + mbwu_state =3D &ris->mbwu_state[ctx->mon]; + if (mbwu_state) { + reset_on_next_read =3D mbwu_state->reset_on_next_read; + mbwu_state->reset_on_next_read =3D false; + } + break; + default: + break; + } + /* * Read the existing configuration to avoid re-writing the same values. * This saves waiting for 'nrdy' on subsequent reads. @@ -1106,7 +1121,7 @@ static void __ris_msmon_read(void *arg) config_mismatch =3D cur_flt !=3D flt_val || cur_ctl !=3D (ctl_val | MSMON_CFG_x_CTL_EN); =20 - if (config_mismatch) { + if (config_mismatch || reset_on_next_read) { write_msmon_ctl_flt_vals(m, ctl_val, flt_val); overflow =3D false; } else if (overflow) { @@ -1264,6 +1279,37 @@ int mpam_msmon_read(struct mpam_component *comp, str= uct mon_cfg *ctx, return err; } =20 +void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ct= x) +{ + struct mpam_msc *msc; + struct mpam_vmsc *vmsc; + struct mpam_msc_ris *ris; + + if (!mpam_is_enabled()) + return; + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list, + srcu_read_lock_held(&mpam_srcu)) { + if (!mpam_has_feature(mpam_feat_msmon_mbwu, &vmsc->props)) + continue; + + msc =3D vmsc->msc; + list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list, + srcu_read_lock_held(&mpam_srcu)) { + if (!mpam_has_feature(mpam_feat_msmon_mbwu, &ris->props)) + continue; + + if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc))) + continue; + + ris->mbwu_state[ctx->mon].correction =3D 0; + ris->mbwu_state[ctx->mon].reset_on_next_read =3D true; + mpam_mon_sel_unlock(msc); + } + } +} + static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd) { u32 num_words, msb; diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_interna= l.h index f3bf26b7fdaf..0061d355ad3e 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -209,6 +209,7 @@ struct mon_cfg { /* Changes to msmon_mbwu_state are protected by the msc's mon_sel_lock. */ struct msmon_mbwu_state { bool enabled; + bool reset_on_next_read; struct mon_cfg cfg; =20 /* @@ -368,6 +369,7 @@ int mpam_apply_config(struct mpam_component *comp, u16 = partid, =20 int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx, enum mpam_device_features, u64 *val); +void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ct= x); =20 int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level, cpumask_t *affinity); --=20 2.43.0