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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 6D018C10F00 for ; Sat, 7 Mar 2020 03:48:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CCC22073C for ; Sat, 7 Mar 2020 03:48:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583552925; bh=dsF84Sqj98Y5uyCZp4EE6mHCp+OeA7YI7cckcIGR2SU=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=j5iWkMQIftiKI1u2P+5eJGCb2lW4jYKExK2IAPROsFGYuyqF66PFfbc2D3Dm1OIQb 9HXyQfH1bw1VDu1qdI+Olm4olbeeOX20Y9PMAmCKONjFpIWTSu/6g0GKam+uLxhkYO wZ15MSrtQvm36rQv3YxITWOSJ2xJ12m9bsUAFkQI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726766AbgCGDso (ORCPT ); Fri, 6 Mar 2020 22:48:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:46448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726307AbgCGDsn (ORCPT ); Fri, 6 Mar 2020 22:48:43 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (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 1B3C32072D; Sat, 7 Mar 2020 03:48:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583552923; bh=dsF84Sqj98Y5uyCZp4EE6mHCp+OeA7YI7cckcIGR2SU=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=YklI/t6Xvzh4qZAL8iY7bD16kQU2cu1p/qf2jF8TuLuQLZbQNM+Prmghd8eJPwOrX AHM+cFvWyPgnf5q/GaB/kFQAQSv4Vg6gJFi0oKWE1rrMqCLu9B/KCAQRXiV6wG0DHI mPUSw7uPiC3m0rLWGoTguiHljzqAbDdC30Y8+sOM= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id DF5E33522891; Fri, 6 Mar 2020 19:48:42 -0800 (PST) Date: Fri, 6 Mar 2020 19:48:42 -0800 From: "Paul E. McKenney" To: Thomas Gleixner Cc: LKML , x86@kernel.org, Paolo Bonzini , KVM Subject: Re: [patch 2/2] x86/kvm: Sanitize kvm_async_pf_task_wait() Message-ID: <20200307034842.GM2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200306234204.847674001@linutronix.de> <20200307000259.448059232@linutronix.de> <20200307002210.GJ2935@paulmck-ThinkPad-P72> <874kv1asf2.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <874kv1asf2.fsf@nanos.tec.linutronix.de> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 07, 2020 at 02:02:25AM +0100, Thomas Gleixner wrote: > "Paul E. McKenney" writes: > >> In #2c RCU is eventually not watching, but as that state cannot schedule > >> anyway there is no point to worry about it so it has to invoke > >> rcu_irq_enter() before running that code. This can be optimized, but this > >> will be done as an extra step in course of the entry code consolidation > >> work. > > > > In other words, any needed rcu_irq_enter() and rcu_irq_exit() are added > > in one of the entry-code consolidation patches, and patch below depends > > on that patch, correct? > > No. The patch itself is already correct when applied to mainline. It has > no dependencies. > > It invokes rcu_irq_enter()/exit() for the case (#2c) where it is > relevant. All other case are already RCU safe today. > > The fact that the invocation is misplaced is a different story and yes, > that is part of the entry code cleanup along with some optimization > which are possible once the entry voodoo is out of ASM and adjustable > for a particular entry point in C. The weekend clearly did not come a moment too soon for me, did it? :-/ Thanx, Paul