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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 1AC74C2D0D2 for ; Thu, 19 Dec 2019 18:43:44 +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 DDD9E24683 for ; Thu, 19 Dec 2019 18:43:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="aDdE9X7h" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDD9E24683 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46578 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ii0lz-0004l7-2L for qemu-devel@archiver.kernel.org; Thu, 19 Dec 2019 13:43:43 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:58253) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ii0l6-00045v-MW for qemu-devel@nongnu.org; Thu, 19 Dec 2019 13:42:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ii0l4-000863-IM for qemu-devel@nongnu.org; Thu, 19 Dec 2019 13:42:47 -0500 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:2037) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ii0l4-0007xB-7j for qemu-devel@nongnu.org; Thu, 19 Dec 2019 13:42:46 -0500 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 19 Dec 2019 10:42:34 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Thu, 19 Dec 2019 10:42:44 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Thu, 19 Dec 2019 10:42:44 -0800 Received: from [10.40.100.125] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 19 Dec 2019 18:42:34 +0000 Subject: Re: [PATCH v10 Kernel 4/5] vfio iommu: Implementation of ioctl to for dirty pages tracking. To: Alex Williamson References: <1576527700-21805-1-git-send-email-kwankhede@nvidia.com> <1576527700-21805-5-git-send-email-kwankhede@nvidia.com> <20191217051513.GE21868@joy-OptiPlex-7040> <17ac4c3b-5f7c-0e52-2c2b-d847d4d4e3b1@nvidia.com> <20191218143902.3c9b06df@x1.home> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <6667e0b4-f3da-6283-3f27-c1cba3d13117@nvidia.com> Date: Fri, 20 Dec 2019 00:12:30 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20191218143902.3c9b06df@x1.home> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1576780954; bh=yc7GPjS2kHBED4VdPZXolDx+lH4rl8plLC7emiHQM9Y=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=aDdE9X7hlKg0NJn0sJaTZNo0MTuiG4d64RSe4TPiXRIALTAxP18ZR5cYNcoZHzzvn OtP6OzpMX0GqyYezSK1FGttePQ80pS8M8cnHw3BfPH5mxZ4sbjZhEECbOLzFOHbiye /se+vcJ3rvXPYqiTJSZMTER4gm/q6YSViRZYIhAtH5HDJmTQfkrokCY1vWmaz3KIXD XwpKSX6J4MnX3t9bYV6a4bk3TeNVyBRGqWA1C8MYMagB6a4axgFJsI2qQAtJ0c2krZ Lj55MC2S5oMhGFfPxDAFZAo2n+5nMjjeQ2B1G4784UBMfSC8BxLIPnqmyqiUIuUAoF tGRjvXrylk5Rw== X-detected-operating-system: by eggs.gnu.org: Windows 7 or 8 [fuzzy] X-Received-From: 216.228.121.65 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: "Zhengxiao.zx@Alibaba-inc.com" , "Tian, Kevin" , "Liu, Yi L" , "cjia@nvidia.com" , "kvm@vger.kernel.org" , "eskultet@redhat.com" , "Yang, Ziye" , "qemu-devel@nongnu.org" , "cohuck@redhat.com" , "shuangtai.tst@alibaba-inc.com" , "dgilbert@redhat.com" , "Wang, Zhi A" , "mlevitsk@redhat.com" , "pasic@linux.ibm.com" , "aik@ozlabs.ru" , "eauger@redhat.com" , "felipe@nutanix.com" , "jonathan.davies@nutanix.com" , Yan Zhao , "Liu, Changpeng" , "Ken.Xue@amd.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/19/2019 3:09 AM, Alex Williamson wrote: > On Tue, 17 Dec 2019 14:54:14 +0530 > Kirti Wankhede wrote: > >> On 12/17/2019 10:45 AM, Yan Zhao wrote: >>> On Tue, Dec 17, 2019 at 04:21:39AM +0800, Kirti Wankhede wrote: >>>> + } else if (range.flags & >>>> + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) { >>>> + uint64_t iommu_pgmask; >>>> + unsigned long pgshift = __ffs(range.pgsize); >>>> + unsigned long *bitmap; >>>> + long bsize; >>>> + >>>> + iommu_pgmask = >>>> + ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; >>>> + >>>> + if (((range.pgsize - 1) & iommu_pgmask) != >>>> + (range.pgsize - 1)) >>>> + return -EINVAL; >>>> + >>>> + if (range.iova & iommu_pgmask) >>>> + return -EINVAL; >>>> + if (!range.size || range.size > SIZE_MAX) >>>> + return -EINVAL; >>>> + if (range.iova + range.size < range.iova) >>>> + return -EINVAL; >>>> + >>>> + bsize = verify_bitmap_size(range.size >> pgshift, >>>> + range.bitmap_size); >>>> + if (bsize) >>>> + return ret; >>>> + >>>> + bitmap = kmalloc(bsize, GFP_KERNEL); >>>> + if (!bitmap) >>>> + return -ENOMEM; >>>> + >>>> + ret = copy_from_user(bitmap, >>>> + (void __user *)range.bitmap, bsize) ? -EFAULT : 0; >>>> + if (ret) >>>> + goto bitmap_exit; >>>> + >>>> + iommu->dirty_page_tracking = false; >>> why iommu->dirty_page_tracking is false here? >>> suppose this ioctl can be called several times. >>> >> >> This ioctl can be called several times, but once this ioctl is called >> that means vCPUs are stopped and VFIO devices are stopped (i.e. in >> stop-and-copy phase) and dirty pages bitmap are being queried by user. > > Do not assume how userspace works or its intent. If dirty tracking is > on, it should remain on until the user turns it off. We cannot assume > userspace uses a one-shot approach. Thanks, > Dirty tracking should be on until user turns it off or user reads bitmap, right? This ioctl is used to read bitmap. Thanks, Kirti