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=-2.3 required=3.0 tests=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 42F74CA9ECB for ; Thu, 31 Oct 2019 14:14:08 +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 14A1C20873 for ; Thu, 31 Oct 2019 14:14:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EulCIaDY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14A1C20873 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=va5hCDW0ENQeX/yj6hQ7QVbHUhqe5WxBNARaO0dli/E=; b=EulCIaDYFXsWy/g2k1fcsF0Ur 9Eg78NMV5GzC92c3f/RDfISKhJ+AE8Ec0qxK1kfGSime/Ri+TwtlQfGNOyMxirqBwkFPPeGsvIbo9 tOrrkMxk/hmJhDzP2Vub+rym9KcL5+u4ncG+yKs+EAixskapLYZhWOBVWOD1tyJSlQDNE1qtXZWkL U9VjU5DnTHX+WSp0a7dcniB2dHXmBjhgMU2Mj6r8ecc25SV85jJ8RePiaH+FzMi930KZJo0ZjXXIH XyC4ltTRX7dfJ9V6IeKESXN1MgFShgncmnrk0QeH2AXwB0ONUIGsljXU8x3kzKCaXoRO6+zGsxP5e YK/wy/N1w==; 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 1iQBD7-0005uz-LN; Thu, 31 Oct 2019 14:14:01 +0000 Received: from lhrrgout.huawei.com ([185.176.76.210] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iQBD4-0005uQ-Iy for linux-arm-kernel@lists.infradead.org; Thu, 31 Oct 2019 14:14:00 +0000 Received: from LHREML710-CAH.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 2481540AB5FECA22A7BF; Thu, 31 Oct 2019 14:13:54 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML710-CAH.china.huawei.com (10.201.108.33) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 31 Oct 2019 14:13:53 +0000 Received: from [127.0.0.1] (10.202.226.45) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Thu, 31 Oct 2019 14:13:53 +0000 Subject: Re: [PATCH v4 0/4] E0PD support To: Will Deacon References: <20191024214207.20588-1-broonie@kernel.org> <20191031112610.GA26059@willie-the-truck> <0152ac71-1295-a302-7810-f9767f7bbd78@huawei.com> <20191031124217.GE26059@willie-the-truck> From: John Garry Message-ID: Date: Thu, 31 Oct 2019 14:13:52 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20191031124217.GE26059@willie-the-truck> Content-Language: en-US X-Originating-IP: [10.202.226.45] X-ClientProxiedBy: lhreml716-chm.china.huawei.com (10.201.108.67) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191031_071358_772265_B5D29028 X-CRM114-Status: GOOD ( 15.33 ) 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: Catalin Marinas , Mark Brown , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 31/10/2019 12:42, Will Deacon wrote: > On Thu, Oct 31, 2019 at 12:13:35PM +0000, John Garry wrote: >> On 31/10/2019 11:26, Will Deacon wrote: >>> On Thu, Oct 24, 2019 at 10:42:03PM +0100, Mark Brown wrote: >>>> This series adds support for E0PD. We enable E0PD unconditionally where >>>> present on systems where all the CPUs in the system support E0PD and >>>> change to not enabling KPTI by default on systems where we have enabled >>>> E0PD. It also converts the runtime checks for use of non-global mappings >>>> into a variable. >>> >>> Although I welcome the simplification introduced by this patch set, I'm >>> worried that we might be removing a significant optimisation to KASLR >>> boot-time on machines with large memory. John reported issues with this >>> in the past, so I'm looping him in in case he has a chance to test this >>> (branch here [1]). Of course, I could just be missing something since >>> this code was really subtle to begin with. >> >> I booted our D05 and D06 boards with that branch and did not experience the >> pauses which we reported some time ago. > > Hmm. So I annotated the code locally and I see that we do rewrite swapper > in this case, so I'm surprised you're not seeing the performance issue > you ran into with this before. Have you got KASLR enabled and are you > passing a non-zero seed? Just to confirm: yes and no (both boards pump out "EFI_RNG_PROTOCOL unavailable, no randomness supplied") Thanks, John > > Will > . > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel