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 0C573C53200 for ; Thu, 30 Jul 2026 01:34:22 +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=quLfiHhuhZ4rZmR4UvnAX3/eBCRvvPk2hc96l8xk9uA=; b=uvXB4aVXo5lvY81uqYEb3NiG2A YkqzAbOsc5A+KQFjYe10XpK2TomOKt42C0f1wWWb5FJz7EmLSPOqnWKXg7QPUXpbh8nr6TTW9YFrE X+yRiyAJZgYOPQtpsUncLQ/hzUQ0R4aOgNhzCpGvm286TWBEQMJJvJMIIFaqTemrSTNH2gKItiYN5 /5U0/yA6b8SLh4m4cpYR3mQE1ZL7+46JKUDRUz1H23YEkADwNWmpgDFwixD+Hp6eqBpthYnmHEBe3 PJg64awv/KctZoZlrdkh6jxq0oxQ94Q7k3enhSlW4Vp9s34h7Jmhll9OjpxTkoVaJfDfU/kOjYdZ3 F364DwZw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wpFf5-00000009GEK-3pV9; Thu, 30 Jul 2026 01:34:15 +0000 Received: from trager.us ([52.5.81.116]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wpFf3-00000009GDv-3AuT for linux-arm-kernel@lists.infradead.org; Thu, 30 Jul 2026 01:34:14 +0000 Received: from c-73-254-161-40.hsd1.wa.comcast.net ([73.254.161.40] helo=[192.168.1.226]) by trager.us with esmtpsa (TLSv1.3:TLS_AES_128_GCM_SHA256:128) (Exim 4.92.3) (envelope-from ) id 1wpFen-0008Ic-CM; Thu, 30 Jul 2026 01:33:57 +0000 Message-ID: <2228a2be-96b1-4c8a-9786-6ba07fd302c0@trager.us> Date: Wed, 29 Jul 2026 18:33:49 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 03/10] arm_mpam: propagate MSC access errors for MBWU counters To: Andre Przywara , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Ben Horgan , Reinette Chatre , Fenghua Yu Cc: Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260729134124.2506269-1-andre.przywara@arm.com> <20260729134124.2506269-4-andre.przywara@arm.com> Content-Language: en-US From: Lee Trager In-Reply-To: <20260729134124.2506269-4-andre.przywara@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260729_183413_827246_D0D72A70 X-CRM114-Status: GOOD ( 11.65 ) 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 On 7/29/26 6:41 AM, Andre Przywara wrote: > @@ -1767,6 +1781,7 @@ static int mpam_save_mbwu_state(void *arg) > { > int i; > u64 val; > + int ret; > struct mon_cfg *cfg; > u32 cur_flt, cur_ctl, mon_sel; > struct mpam_msc_ris *ris = arg; > @@ -1777,7 +1792,8 @@ static int mpam_save_mbwu_state(void *arg) > mbwu_state = &ris->mbwu_state[i]; > cfg = &mbwu_state->cfg; > > - if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc))) > + ACQUIRE(mon_sel_lock, guard)(msc); > + if (ACQUIRE_ERR(mon_sel_lock, &guard)) > return -EIO; > > mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, i) | > @@ -1788,7 +1804,9 @@ static int mpam_save_mbwu_state(void *arg) > mpam_write_monsel_reg(msc, CFG_MBWU_CTL, 0); > > if (mpam_ris_has_mbwu_long_counter(ris)) { > - val = mpam_msc_read_mbwu_l(msc); > + ret = mpam_msc_read_mbwu_l(msc, &val); > + if (ret) > + return ret; > mpam_msc_zero_mbwu_l(msc); > } else { > u32 val32; I think checking for (val & MSMON____L_NRDRY) is still required before updating the saved state. mpam_msc_read_mbw_l() can return 0 while setting val to MSMON___L_NRDY when it cannot obtain a stable value. The state saving path later adds val to mbwu_state->correction, so the sentinel would corrupt the saved correction. Additionally, as Ben noted during the v3 review, hardware may also set the NRDY bit. > @@ -1804,7 +1822,6 @@ static int mpam_save_mbwu_state(void *arg) > cfg->partid = FIELD_GET(MSMON_CFG_x_FLT_PARTID, cur_flt); > mbwu_state->correction += val; > mbwu_state->enabled = FIELD_GET(MSMON_CFG_x_CTL_EN, cur_ctl); > - mpam_mon_sel_unlock(msc); > } > > return 0;