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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 3F9E0C433FE for ; Thu, 10 Dec 2020 02:55:04 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 7A9812332A for ; Thu, 10 Dec 2020 02:55:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A9812332A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:50978 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1knC6g-000642-E2 for qemu-devel@archiver.kernel.org; Wed, 09 Dec 2020 21:55:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56622) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1knC5P-0005dF-BZ for qemu-devel@nongnu.org; Wed, 09 Dec 2020 21:53:43 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:2472) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1knC5N-0006y1-0b for qemu-devel@nongnu.org; Wed, 09 Dec 2020 21:53:42 -0500 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Crz431S01zM2pY; Thu, 10 Dec 2020 10:52:51 +0800 (CST) Received: from [10.174.187.37] (10.174.187.37) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Thu, 10 Dec 2020 10:53:24 +0800 Subject: Re: [PATCH] kvm: Take into account the unaligned section size when preparing bitmap To: Peter Xu References: <20201208114013.875-1-yuzenghui@huawei.com> <20201208151654.GA6432@xz-x1> <6dc82702-9246-4684-4f28-e104abc0c11d@huawei.com> <20201210020843.GB3211@xz-x1> From: zhukeqian Message-ID: <7d46e5ca-24ab-7c44-201c-77e8fc6a2ace@huawei.com> Date: Thu, 10 Dec 2020 10:53:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20201210020843.GB3211@xz-x1> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.187.37] X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.191; envelope-from=zhukeqian1@huawei.com; helo=szxga05-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zenghui Yu , pbonzini@redhat.com, qemu-devel@nongnu.org, wanghaibin.wang@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/12/10 10:08, Peter Xu wrote: > Keqian, > > On Thu, Dec 10, 2020 at 09:46:06AM +0800, zhukeqian wrote: >> Hi, >> >> I see that if start or size is not PAGE aligned, it also clears areas >> which beyond caller's expectation, so do we also need to consider this? > > Could you elaborate? > > If start_delta != 0, kvm_log_clear_one_slot() should already go the slow path. > > Thanks, > Hi Peter, start_delta /= psize; If start is not PAGE aligned, then start_delta is not PAGE aligned. so I think the above code will implicitly extend our start to be PAGE aligned. I suggest that we should shrink the start and (start + size) to be PAGE aligned at beginning of this function. Maybe I miss something? Keqian.