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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 3D028C43331 for ; Tue, 31 Mar 2020 09:45:31 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 073BA208E0 for ; Tue, 31 Mar 2020 09:45:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="FhRc0s8P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 073BA208E0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=krmPs5hO0TLlJp3Tjic4Ca9G1uFjktPbRXAFLM7iR68=; b=FhRc0s8P/9OFo0 T1ntUPeSw6kotrbia21Th7OGB+oR3e6T5c8G2vWPztC4W3DVMwyXmKYofKNLiXlxSdD3hu2yk/jur yGSybgt2v+WAOSOA5QgjmQ/zMtnddRNIIGHbiT9R03S2vmDttuqhbLjmDCG22y8kz1SdKO1e80s+P tImxiB4AMMcqKu+i2qdIwupO3C2tOSq54BymXFDpQAwzYFA26Hzls4M/POEa6H3UsguYYFZtNn/SS xBuyS/AZceQQctWa7+NwaMo7CEwpaJ9MKyIjJ82oc/hmNKGAh+z1HeZkmmIpEUDrnTrFGobk1RCm5 N91Zb5Fyrgli1d81wgeg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jJDSb-0001xJ-OB; Tue, 31 Mar 2020 09:45:29 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jJDSY-0001wp-Qi for linux-arm-kernel@lists.infradead.org; Tue, 31 Mar 2020 09:45:28 +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 6081430E; Tue, 31 Mar 2020 02:45:25 -0700 (PDT) Received: from C02TD0UTHF1T.local (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DDBD43F52E; Tue, 31 Mar 2020 02:45:22 -0700 (PDT) Date: Tue, 31 Mar 2020 10:45:11 +0100 From: Mark Rutland To: Andrea Arcangeli Subject: Re: [PATCH 3/3] arm64: tlb: skip tlbi broadcast Message-ID: <20200331094034.GA1131@C02TD0UTHF1T.local> References: <20200223192520.20808-1-aarcange@redhat.com> <20200223192520.20808-4-aarcange@redhat.com> <20200309112242.GB2487@mbp> <20200314031609.GB2250@redhat.com> <20200316140906.GA6220@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200316140906.GA6220@lakrids.cambridge.arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200331_024526_910174_19DBAA8F X-CRM114-Status: UNSURE ( 9.74 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: QI Fuli , Rafael Aquini , Jon Masters , Catalin Marinas , linux-kernel@vger.kernel.org, Michal Hocko , linux-mm@kvack.org, Mark Salter , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Andrea, On Mon, Mar 16, 2020 at 02:09:07PM +0000, Mark Rutland wrote: > AFAICT, this series relies on: > > * An ISB completing prior page table walks when updating TTBR. I don't > believe this is necessarily the case, given how things work for an > EL1->EL2 transition where there can be ongoing EL1 walks. I've had confirmation that a DSB is necessary (after the MSR and ISB) to complete any ongoing translation table walks for the stale context. Without a DSB, those walks can observe subsequent stores and encounter the usual set of CONSTRAINED UNPREDICTABLE behaviours (e.g. walking into MMIO with side-effects, continuing from amalgamted entries, etc). Those issues are purely to do with the walk, and apply regardless of whether the resulting translations are architecturally consumed. > * Walks never being initiated for `inactive` contexts within the current > translation regime. e.g. while ASID x is installed, never starting a > walk for ASID y. I can imagine that the architecture may permit a form > of this starting with intermediate walk entries in the TLBs. I'm still chasing this point. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel