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 6A49FC5518F for ; Tue, 4 Aug 2026 09:54:59 +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=lWf5Vr71FePF2RNlNaysEEmwoRAlNyEkV3VHONBQCKw=; b=SYsOFCyWnk3pU5zpqdqNrfQu/b QLehn4hmWGc2srNdyPeC9UZuYLcEjNE6GplxDX1zDAFZSiOopIN+h4UJIPMcZ76tr4rKGCfSkbtn0 qPXBWXJDJbNWmN6x4XNkbVeF0uNflwMBCe1qrJcSA8rGc5vhr0XPjRn1ZtxNSd267lTuIm2HlkTvQ 2L7LIUBoolFqArivoKvkL7WxHo4CwWA3z+7tZRxCqY9v9MYEbOKwaFBoqtJ3b+rMisiaT8LH41oxq Je3XZtvUd+ZD3HMIrI6mICsEPT2HNxdq9VmXH1yZXuFruFawbo9sQ8xQ1e7sKNkqRcDWAe2jQg5k4 /30tb5HA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrBrC-00000001TMF-3vV3; Tue, 04 Aug 2026 09:54:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrBr7-00000001TLH-36RE for linux-arm-kernel@lists.infradead.org; Tue, 04 Aug 2026 09:54:43 +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 D26601476; Tue, 4 Aug 2026 02:54:35 -0700 (PDT) Received: from [192.168.178.24] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EEBF03F66F; Tue, 4 Aug 2026 02:54:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785837279; bh=XHZ8Hn1v8UipXDtFoVeXGBoWJHqviZySPsof6RP0r40=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=S1+IOk0W+TSwCHa0LsWc7vuTiAIYvzmGB8EH+zDJ+rwqGOjxDsYXhJFHcsZZbB8xK ZlJpgJLhu2475SS1WnJmA5Om/MTrDqmFoW9TfNbg/4WU1+xpzrNvqNWGIDbRyCxIhV GUDksdC4d0BLkEQAaWEritumj0kjMca+EWf/MBcY= Message-ID: <2aa75a48-d514-42a2-afda-d7b3357c585a@arm.com> Date: Tue, 4 Aug 2026 11:54:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 07/11] arm_mpam: propagate MSC access errors for mpam_reprogram_ris_partid() To: Srivathsa L Rao , 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 , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , Lee Trager , Ritwick Sharma , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260731170324.2927758-1-andre.przywara@arm.com> <20260731170324.2927758-8-andre.przywara@arm.com> <836c6c2b-6ab0-4dba-9964-aa65ddcb7381@oss.qualcomm.com> Content-Language: en-GB From: Andre Przywara In-Reply-To: <836c6c2b-6ab0-4dba-9964-aa65ddcb7381@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260804_025442_324418_5B2FEE03 X-CRM114-Status: GOOD ( 17.66 ) 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, On 8/4/26 07:57, Srivathsa L Rao wrote: > Hi Andre, > > mpam_reprogram_ris_partid() writes hardware registers sequentially. > If a write fails midway (possible on PCC MSCs via SCMI), the earlier > writes are already committed and the hardware is left in a partially > configured state. > Currently this is safe only because mpam_fb_disable_mpam() tears > everything down on any firmware error. If that behavior is ever > relaxed (e.g. for transient BUSY handling), a partial state could > persist and produce weird behavior? > > I wanted to point this as a design note. Yes, this might be a potential problem, but as you said at the moment we tear down MPAM anyway. I don't know if we can ever really handle MPAM-Fb errors in a meaningful way, but indeed a retry-if-busy seems a worthwhile addition - at a later time ;-) Thanks for all the reviews and comments! Cheers, Andre > On 7/31/2026 10:33 PM, Andre Przywara wrote: >> Allow the mpam_reprogram_ris_partid() function check for and return >> errors, and propagate MSC read and write errors from the lower level up. >> This also covers the callers of this function: mpam_reset_ris() and >> apply_config(). >> >> Signed-off-by: Andre Przywara >> --- >>   drivers/resctrl/mpam_devices.c | 136 ++++++++++++++++++++++----------- >>   1 file changed, 93 insertions(+), 43 deletions(-) >> >> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/ >> mpam_devices.c >> index 38450c55e45e..32088ad1d67e 100644 >> --- a/drivers/resctrl/mpam_devices.c >> +++ b/drivers/resctrl/mpam_devices.c >> @@ -1601,7 +1601,7 @@ void mpam_msmon_reset_mbwu(struct mpam_component >> *comp, struct mon_cfg *ctx) >>       } >>   } >>   ... > >> +static int mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 >> partid, >> +                     struct mpam_config *cfg) >>   { >>       u32 pri_val = 0; >>       .. >> -    mutex_unlock(&msc->part_sel_lock); >> +    return 0; >>   } > -- > > Best Regards, > Srivathsa