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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5C11C47082 for ; Tue, 8 Jun 2021 15:29:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB2D6611AE for ; Tue, 8 Jun 2021 15:29:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231268AbhFHPbU (ORCPT ); Tue, 8 Jun 2021 11:31:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:50746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230392AbhFHPbS (ORCPT ); Tue, 8 Jun 2021 11:31:18 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A4063610F8; Tue, 8 Jun 2021 15:29:25 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1lqdfP-006EHQ-JA; Tue, 08 Jun 2021 16:29:23 +0100 Date: Tue, 08 Jun 2021 16:29:14 +0100 Message-ID: <87a6o0z86t.wl-maz@kernel.org> From: Marc Zyngier To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Lorenzo Pieralisi , Vincenzo Frascino , Mark Rutland Subject: Re: [RFC PATCH v2 00/10] irqchip/irq-gic: Optimize masking by leveraging EOImode=1 In-Reply-To: <87tumhg9vm.mognet@arm.com> References: <20210525173255.620606-1-valentin.schneider@arm.com> <87zgwgs9x0.wl-maz@kernel.org> <87tumhg9vm.mognet@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: valentin.schneider@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, lorenzo.pieralisi@arm.com, vincenzo.frascino@arm.com, mark.rutland@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+Mark, since we discussed about this on IRC] Hi Valentin, On Tue, 01 Jun 2021 11:25:01 +0100, Valentin Schneider wrote: > > On 27/05/21 12:17, Marc Zyngier wrote: > > On Tue, 25 May 2021 18:32:45 +0100, > > Valentin Schneider wrote: > >> I've tested this on my Ampere eMAG, which uncovered "fun" interactions with > >> the MSI domains. Did the same trick as the Juno with the pl011. > >> > >> pNMIs cause said eMAG to freeze, but that's true even without my patches. I > >> did try them out under QEMU+KVM and that looked fine, although that means I > >> only got to test EOImode=0. I'll try to dig into this when I get some more > >> cycles. > > > > That's interesting/worrying. As far as I remember, this machine uses > > GIC500, which is a well known quantity. If pNMIs are causing issues, > > that'd probably be a CPU interface problem. Can you elaborate on how > > you tried to test that part? Just using the below benchmark? > > > > Not even that, it would hang somewhere at boot. Julien suggested offline > that it might be a problem with the secondaries' PMR initial value, but I > really never got to do dig into it. I just hit a similar problem on an Altra box, which seems to be related to using PSCI for idle. PSCI has no idea about priority masking, and enters CPU suspend with interrupt masked at the PMR level. Good luck waking up from that. I've pushed a test branch at [1]. It'd be really good if you could have a quick look and let me know if that helps in your case (it certainly does on the box I have access to). Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=arm64/nmi-idle -- Without deviation from the norm, progress is not possible.