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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 34C06C4332F for ; Mon, 7 Nov 2022 17:17:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sg6pXp1Gw94EAx/GUa6DIjDFVsEGMMYb625WCObB2OY=; b=a263Ir+Sse6swT 6whRuRtPbVJrl6ZjZ8B0hibHk22afDmqUSwx7DOTuGtkxap7BGeLxZDv4MCkeGR/eb+HD3op9QE8G 5cjyYIvNpPZ6Kpd6Gfyr/rBXLdEw85biO/zWlEDCiyceb6BlZcOlrvf0hv5HHWTlEcQPTzGjppPI6 b93UU2YpzsxKa+egzavvgRqLXzkGW3Dm84WuBiAesDbqXw9EzP5Qc0mn1PyvZacqzHLWstdQ93o6b 91+6LaZtzFSIjwB883GPruShyQ5tVYB/R16PqQjHpOfcIYHVoLDBwm8/YsPey2yBm7vrUUma/lRaH MkDfGW137tnvbHN/rS0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1os5jo-00GatJ-5e; Mon, 07 Nov 2022 17:16:44 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1os5jl-00Gas7-Na for linux-arm-kernel@lists.infradead.org; Mon, 07 Nov 2022 17:16:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667841400; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=sAQme1GAbPodTq1JRNMk+uId/J7lODmXvvWt4/unp6w=; b=VqWikdZJiVeYu9BnLxHnx0RQVPJEWHenbL77T1atDsuNa4kB9ahub1xrrd1xM+pcbsx3T7 UjzLIDrSsMfu+qSRoV5drji/lQWas+NLNIAiG9rLn1Uh+3B/UcFAWoRbbLwgSsjqzOKvMT C7yiRoSIMvYn1Vkf9I2zZWMDomYoO7w= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-267-ukFuae4ENwyQK-cdkoEeEA-1; Mon, 07 Nov 2022 12:16:35 -0500 X-MC-Unique: ukFuae4ENwyQK-cdkoEeEA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4CC881C07596; Mon, 7 Nov 2022 17:16:34 +0000 (UTC) Received: from localhost (unknown [10.39.193.202]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EAB3A140EBF5; Mon, 7 Nov 2022 17:16:33 +0000 (UTC) From: Cornelia Huck To: Peter Collingbourne , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Cc: Catalin Marinas , Will Deacon , Marc Zyngier , Evgenii Stepanov , kvm@vger.kernel.org, Steven Price , Vincenzo Frascino , Peter Collingbourne Subject: Re: [PATCH v5 5/8] arm64: mte: Lock a page for MTE tag initialisation In-Reply-To: <20221104011041.290951-6-pcc@google.com> Organization: Red Hat GmbH References: <20221104011041.290951-1-pcc@google.com> <20221104011041.290951-6-pcc@google.com> User-Agent: Notmuch/0.37 (https://notmuchmail.org) Date: Mon, 07 Nov 2022 18:16:32 +0100 Message-ID: <87iljq3csv.fsf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221107_091641_862863_83EB2548 X-CRM114-Status: GOOD ( 17.09 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Thu, Nov 03 2022, Peter Collingbourne wrote: > From: Catalin Marinas > > Initialising the tags and setting PG_mte_tagged flag for a page can race > between multiple set_pte_at() on shared pages or setting the stage 2 pte > via user_mem_abort(). Introduce a new PG_mte_lock flag as PG_arch_3 and > set it before attempting page initialisation. Given that PG_mte_tagged > is never cleared for a page, consider setting this flag to mean page > unlocked and wait on this bit with acquire semantics if the page is > locked: > > - try_page_mte_tagging() - lock the page for tagging, return true if it > can be tagged, false if already tagged. No acquire semantics if it > returns true (PG_mte_tagged not set) as there is no serialisation with > a previous set_page_mte_tagged(). > > - set_page_mte_tagged() - set PG_mte_tagged with release semantics. > > The two-bit locking is based on Peter Collingbourne's idea. > > Signed-off-by: Catalin Marinas > Signed-off-by: Peter Collingbourne > Reviewed-by: Steven Price > Cc: Will Deacon > Cc: Marc Zyngier > Cc: Peter Collingbourne > --- > arch/arm64/include/asm/mte.h | 35 +++++++++++++++++++++++++++++++- > arch/arm64/include/asm/pgtable.h | 4 ++-- > arch/arm64/kernel/cpufeature.c | 2 +- > arch/arm64/kernel/mte.c | 12 +++-------- > arch/arm64/kvm/guest.c | 16 +++++++++------ > arch/arm64/kvm/mmu.c | 2 +- > arch/arm64/mm/copypage.c | 2 ++ > arch/arm64/mm/fault.c | 2 ++ > arch/arm64/mm/mteswap.c | 14 +++++-------- > 9 files changed, 60 insertions(+), 29 deletions(-) Reviewed-by: Cornelia Huck _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel