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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id B680FECAAD8 for ; Fri, 23 Sep 2022 14:49:16 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 227F040C67; Fri, 23 Sep 2022 10:49:16 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RXvDuyYkmvMh; Fri, 23 Sep 2022 10:49:15 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1FB3040C94; Fri, 23 Sep 2022 10:49:15 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1B4E040C67 for ; Fri, 23 Sep 2022 10:49:14 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wfLHS4y6yQRI for ; Fri, 23 Sep 2022 10:49:13 -0400 (EDT) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id E421240BA3 for ; Fri, 23 Sep 2022 10:49:12 -0400 (EDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8C981B837C6; Fri, 23 Sep 2022 14:49:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35975C433C1; Fri, 23 Sep 2022 14:49:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663944550; bh=Brt1hC9cedCPxBKNV0KPrjmKpIq98or1KU3mRPCeba4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=n43WjpcmPw3bKySrWauXKpXVrijSfIWmOg9XZJIVtOQTzDFMjBGNgVq8ccgM1Z9Pn kRmAqc+1mncpmALKxDbS6Ei9FAZv6TySTT6F38+94U/3i0HpbJb3j+CN6q15jzgsxi Fovud/O4QkKb2zkAdc6rwew3nqYxOiXw1lra+TEXNyUAx+aOc58a+fPlD4AVgGlFqg yf5r7VxgWOOXa7ejvvaNbGQrRP3SKNkwqs3kqri8CXTcSHvoxiiq1o+GS5t/m4UWwM jXdl1OUNUC/WLoqe5OR0n5BkARQkO3JbZnHiwJznTvfOVbhpjcL6gxSX2fzCvgK7mW Mknvx6RT0SU6w== Received: from [82.141.251.28] (helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1objzH-00CB1U-WF; Fri, 23 Sep 2022 15:49:08 +0100 Date: Fri, 23 Sep 2022 15:49:07 +0100 Message-ID: <87a66qjgd8.wl-maz@kernel.org> From: Marc Zyngier To: Paolo Bonzini Subject: Re: [PATCH 5/6] KVM: selftests: dirty-log: Upgrade dirty_gfn_set_collected() to store-release In-Reply-To: References: <20220922170133.2617189-1-maz@kernel.org> <20220922170133.2617189-6-maz@kernel.org> 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") X-SA-Exim-Connect-IP: 82.141.251.28 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, catalin.marinas@arm.com, bgardon@google.com, shuah@kernel.org, andrew.jones@linux.dev, will@kernel.org, dmatlack@google.com, peterx@redhat.com, zhenyzha@redhat.com, shan.gavin@gmail.com, gshan@redhat.com, james.morse@arm.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, oliver.upton@linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev, will@kernel.org, shan.gavin@gmail.com, bgardon@google.com, dmatlack@google.com, zhenyzha@redhat.com, shuah@kernel.org, kvmarm@lists.cs.columbia.edu X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Thu, 22 Sep 2022 22:38:58 +0100, Paolo Bonzini wrote: > > On Thu, Sep 22, 2022 at 7:02 PM Marc Zyngier wrote: > > To make sure that all the writes to the log marking the entries > > as being in need of reset are observed in order, use a > > smp_store_release() when updating the log entry flags. > > > > Signed-off-by: Marc Zyngier > > You also need a load-acquire on the load of gfn->flags in > dirty_gfn_is_dirtied. Otherwise reading cur->slot or cur->offset might > see a stale value. Ah, indeed. smp_wmb() is implemented as DMB ISHST, which only orders writes, and not loads against writes. Global barriers are just confusing. /me goes and repaint the stuff... M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm