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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 6FCBFC433E9 for ; Wed, 17 Feb 2021 11:23:21 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2BF3564DBD for ; Wed, 17 Feb 2021 11:23:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BF3564DBD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=YdRh6rRuU87I+j+920Mxk4gwu4awgPVzUj/6kB+oKvI=; b=Mo1/y6zKGRRv8c+2cqUf9ng9a 8v+jN5dWhkaPhyLRBwBLXMTsQgyZ7UdqvKqBNAY+yG2ImTzOj+wOh2D2autwUb50YueK3kci4+gc9 wQGvfNsdi7wLYZnr0Pq/VeMXeZaB/JaAjJNSH8nNdkjirgDkKaA+T3/i4SMbav9XHPmIUwVZVpRME 0QHK4z/2XE4I3P0nSsu9GmrdagtrYU5dVWj/FbADV502Y1DDmN5+cUf3PZQGf7I6tL/+/HZDzfmiY py/H3RSUVGRK2k/KYd77b6+9VUD0SlySrquzkGSpj15ZExrM9drbqGla4yJJ5nTX8dYbugjq0aaaf QnOaVp1Lw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lCKuH-0001Vm-Cm; Wed, 17 Feb 2021 11:22:09 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lCKuD-0001UP-PW for linux-arm-kernel@lists.infradead.org; Wed, 17 Feb 2021 11:22:06 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5D29C64E57; Wed, 17 Feb 2021 11:22:04 +0000 (UTC) Date: Wed, 17 Feb 2021 11:22:01 +0000 From: Catalin Marinas To: Anshuman Khandual Subject: Re: [PATCH] arm64: kernel: disable CNP on Carmel Message-ID: <20210217112201.GD17184@arm.com> References: <20210217013151.30351-1-rwiley@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210217_062205_919920_EFBCE7D6 X-CRM114-Status: GOOD ( 16.96 ) 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: will@kernel.org, Rich Wiley , 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Feb 17, 2021 at 10:43:52AM +0530, Anshuman Khandual wrote: > On 2/17/21 7:01 AM, Rich Wiley wrote: > > On NVIDIA Carmel cores, CNP behaves differently than it does on standard > > ARM cores. On Carmel, if two cores have CNP enabled and share an L2 TLB > > entry created by core0 for a specific ASID, a non-shareable TLBI from > > core1 may still see the shared entry. On standard ARM cores, that TLBI > > will invalidate the shared entry as well. > > Could you please explain more on "may still see the shared entry" on the > NVIDIA Carmel core vs "invalid the shared entry" on standard ARM core. That's about the CnP feature where more than one core can share the same TLB. > > This causes issues with patchsets that attempt to do local TLBIs based > > A new patchset ? Does it impact any existing functionality ? What sort of > issues this create ? > > > on cpumasks instead of broadcast TLBIs. Avoid these issues by disabling > > Does it affect all existing local TLBI which iterate over cpumask or are > there some particular situations ? The problem description here needs to > be more clear and specific. Local TLBI does not work as described in the ARM ARM w.r.t. CnP, so CnP needs disabling. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel