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=-4.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 AEC24C433DB for ; Fri, 22 Jan 2021 11:49:04 +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 4CD53235F7 for ; Fri, 22 Jan 2021 11:49:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CD53235F7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:To:From: Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=KV3PhhHJjA8IlkFkozNmTG9JHfDcjqZYQ86rca//DDo=; b=jHn0Kd8Ectkb+QQ5d2ARN4S+G gTkCBOaXCI3lY+uzxs7OdV6qgO4jFefzAqHrqF82bQM+laXnO67WV0UCufFcSLcbriu3NdAzbfILD 2OO/gQ4smwme8KENQ1q9PzILBbsVGJxyDcq48OcDUuOZ5Few7S8ELu9GqTfds7UU4Ptmqlx8Q6UDI thPK7TPbjDwLgaxq4P3LZ0centhf12LeXKUPqcmob0FS/n3LxfJpXhuChduiuliffIrAKrIwJB06q ii48TxfTq1oprSAZKeav20+iheBeqwaQJzXUgAA863m/U9zYY28Bb4BrF1VJTCgqK1hPNH1LdzSMU L6ZYtz48A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2uv0-00023F-GH; Fri, 22 Jan 2021 11:47:58 +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 1l2uux-00022i-Lp for linux-arm-kernel@lists.infradead.org; Fri, 22 Jan 2021 11:47:56 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 321AE22CA1; Fri, 22 Jan 2021 11:47:54 +0000 (UTC) Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1l2uuu-009P1V-1R; Fri, 22 Jan 2021 11:47:52 +0000 MIME-Version: 1.0 Date: Fri, 22 Jan 2021 11:47:51 +0000 From: Marc Zyngier To: Yanan Wang Subject: Re: [RFC PATCH v4 0/2] Some optimization for stage-2 translation In-Reply-To: <20210122101358.379956-1-wangyanan55@huawei.com> References: <20210122101358.379956-1-wangyanan55@huawei.com> User-Agent: Roundcube Webmail/1.4.10 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: wangyanan55@huawei.com, will@kernel.org, catalin.marinas@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, gshan@redhat.com, qperret@google.com, wanghaibin.wang@huawei.com, yezengruan@huawei.com, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210122_064755_789087_DCB9F5D9 X-CRM114-Status: GOOD ( 19.54 ) 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: Gavin Shan , kvm@vger.kernel.org, Suzuki K Poulose , Catalin Marinas , Quentin Perret , linux-kernel@vger.kernel.org, yezengruan@huawei.com, James Morse , Julien Thierry , yuzenghui@huawei.com, wanghaibin.wang@huawei.com, Will Deacon , kvmarm@lists.cs.columbia.edu, 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Yanan, On 2021-01-22 10:13, Yanan Wang wrote: > Hi, Will, Marc, > Is there any further comment on the v3 series I post previously? None, I was planning to queue them for 5.12 over the weekend. > If they are not fine to you, then I think maybe we should just turn > back to the original solution in v1, where I suggestted to filter out > the case of only updating access permissions in the map handler and > handle it right there. > > Here are the reasons for my current opinion: > With an errno returned from the map handler for this single case, there > will be one more vcpu exit from guest and we also have to consider the > spurious dirty pages. Besides, it seems that the EAGAIN errno has been > chosen specially for this case and can not be used elsewhere for other > reasons, as we will change this errno to zero at the end of the > function. > > The v1 solution looks like more concise at last, so I refine the diff > and post the v4 with two patches here, just for a contrast. > > Which solution will you prefer now? Could you please let me know. I'm still very much opposed to mixing mapping and permission changes. How bad is the spurious return to a vcpu? Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel