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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 89C6AC47255 for ; Mon, 11 May 2020 10:23:49 +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 53F2F2075E for ; Mon, 11 May 2020 10:23:49 +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="ZWUbJgzE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53F2F2075E 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]:45894 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jY5bA-00051X-DZ for qemu-devel@archiver.kernel.org; Mon, 11 May 2020 06:23:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48594) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jY5aR-0004OW-SC for qemu-devel@nongnu.org; Mon, 11 May 2020 06:23:03 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:8386) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jY5aQ-00040N-0n for qemu-devel@nongnu.org; Mon, 11 May 2020 06:23:03 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 11 May 2020 03:20:45 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 11 May 2020 03:22:59 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 11 May 2020 03:22:59 -0700 Received: from [10.40.102.158] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 11 May 2020 10:22:51 +0000 Subject: Re: [PATCH v16 QEMU 09/16] vfio: Add save state functions to SaveVMHandlers To: Yan Zhao References: <1585084154-29461-1-git-send-email-kwankhede@nvidia.com> <1585084154-29461-10-git-send-email-kwankhede@nvidia.com> <20200509053131.GC26056@joy-OptiPlex-7040> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <7653e660-1360-7c2b-c4c7-3b53081f14e3@nvidia.com> Date: Mon, 11 May 2020 15:52:47 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200509053131.GC26056@joy-OptiPlex-7040> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) 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=1589192445; bh=KDl+/o6qGwx0R5/kJO1avWPC7AlSJPIscAwgZtY6/cQ=; 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=ZWUbJgzEwuIx5OCTaxFNZzKgpJkyml1fDK5BB3QRyRldnaXVUq7Xc4BAugOVhxN+a VGGhbGH9ioUVmcB5KK9ar+4WqkkSNFjN85tm7lZgcwCovNdFvOa/pjE0sCgzU8H5La NqFZcNh3M5N3t29LTFLCIeBbdzPePXifv/7aDpIPYYaRGaDRSroNrXh2hQwWNhU3Sb torvt+tjXPQPpjWsj530UVOS/ID+TiyLfYjr3kchUFOCOGMttpaeUvuvwr6M34+8eu LjZO2eUCFWG7YLAO7BiCX2M/aSM2+9LvLzpeJCStfdgeqj5ofYv2remyR/exHcLrxK KvEVYqJJ9qWbg== Received-SPF: pass client-ip=216.228.121.143; envelope-from=kwankhede@nvidia.com; helo=hqnvemgate24.nvidia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/11 05:53:50 X-ACL-Warn: Detected OS = Windows 7 or 8 [fuzzy] X-Spam_score_int: -70 X-Spam_score: -7.1 X-Spam_bar: ------- X-Spam_report: (-7.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: "Zhengxiao.zx@Alibaba-inc.com" , "Tian, Kevin" , "Liu, Yi L" , "cjia@nvidia.com" , "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" , "alex.williamson@redhat.com" , "eauger@redhat.com" , "felipe@nutanix.com" , "jonathan.davies@nutanix.com" , "Liu, Changpeng" , "Ken.Xue@amd.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/9/2020 11:01 AM, Yan Zhao wrote: > On Wed, Mar 25, 2020 at 05:09:07AM +0800, Kirti Wankhede wrote: >> Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy >> functions. These functions handles pre-copy and stop-and-copy phase. >> >> In _SAVING|_RUNNING device state or pre-copy phase: >> - read pending_bytes. If pending_bytes > 0, go through below steps. >> - read data_offset - indicates kernel driver to write data to staging >> buffer. >> - read data_size - amount of data in bytes written by vendor driver in >> migration region. > I think we should change the sequence of reading data_size and > data_offset. see the next comment below. > >> - read data_size bytes of data from data_offset in the migration region. >> - Write data packet to file stream as below: >> {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data, >> VFIO_MIG_FLAG_END_OF_STATE } >> >> In _SAVING device state or stop-and-copy phase >> a. read config space of device and save to migration file stream. This >> doesn't need to be from vendor driver. Any other special config state >> from driver can be saved as data in following iteration. >> b. read pending_bytes. If pending_bytes > 0, go through below steps. >> c. read data_offset - indicates kernel driver to write data to staging >> buffer. >> d. read data_size - amount of data in bytes written by vendor driver in >> migration region. >> e. read data_size bytes of data from data_offset in the migration region. >> f. Write data packet as below: >> {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data} >> g. iterate through steps b to f while (pending_bytes > 0) >> h. Write {VFIO_MIG_FLAG_END_OF_STATE} >> >> When data region is mapped, its user's responsibility to read data from >> data_offset of data_size before moving to next steps. >> >> Signed-off-by: Kirti Wankhede >> Reviewed-by: Neo Jia >> --- >> hw/vfio/migration.c | 245 +++++++++++++++++++++++++++++++++++++++++- >> hw/vfio/trace-events | 6 ++ >> include/hw/vfio/vfio-common.h | 1 + >> 3 files changed, 251 insertions(+), 1 deletion(-) >> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c >> index 033f76526e49..ecbeed5182c2 100644 >> --- a/hw/vfio/migration.c >> +++ b/hw/vfio/migration.c >> @@ -138,6 +138,137 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, >> return 0; >> } >> >> +static void *find_data_region(VFIORegion *region, >> + uint64_t data_offset, >> + uint64_t data_size) >> +{ >> + void *ptr = NULL; >> + int i; >> + >> + for (i = 0; i < region->nr_mmaps; i++) { >> + if ((data_offset >= region->mmaps[i].offset) && >> + (data_offset < region->mmaps[i].offset + region->mmaps[i].size) && >> + (data_size <= region->mmaps[i].size)) { >> + ptr = region->mmaps[i].mmap + (data_offset - >> + region->mmaps[i].offset); >> + break; >> + } >> + } >> + return ptr; >> +} >> + >> +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev) >> +{ >> + VFIOMigration *migration = vbasedev->migration; >> + VFIORegion *region = &migration->region; >> + uint64_t data_offset = 0, data_size = 0; >> + int ret; >> + >> + ret = pread(vbasedev->fd, &data_offset, sizeof(data_offset), >> + region->fd_offset + offsetof(struct vfio_device_migration_info, >> + data_offset)); >> + if (ret != sizeof(data_offset)) { >> + error_report("%s: Failed to get migration buffer data offset %d", >> + vbasedev->name, ret); >> + return -EINVAL; >> + } >> + >> + ret = pread(vbasedev->fd, &data_size, sizeof(data_size), >> + region->fd_offset + offsetof(struct vfio_device_migration_info, >> + data_size)); >> + if (ret != sizeof(data_size)) { >> + error_report("%s: Failed to get migration buffer data size %d", >> + vbasedev->name, ret); >> + return -EINVAL; >> + } > data_size should be read first, and if it's 0, data_offset will not > be read further. > > the reasons are below: > 1. if there's no data region provided by vendor driver, there's no > reason to get a valid data_offset, so reading/writing of data_offset > should fail. And this should not be treated as a migration error. > > 2. even if pending_bytes is 0, vfio_save_iterate() is still possible to be > called and therefore vfio_save_buffer() is called. > As I mentioned in reply to Alex in: https://lists.nongnu.org/archive/html/qemu-devel/2020-05/msg02476.html With that, vfio_save_iterate() will read pending_bytes if its 0 and then if pending_bytes is not 0 then call vfio_save_buffer(). With that your above concerns should get resolved. Thanks, Kirti