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=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 2384BC433DF for ; Mon, 18 May 2020 03:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E14C420715 for ; Mon, 18 May 2020 03:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726726AbgERDqv (ORCPT ); Sun, 17 May 2020 23:46:51 -0400 Received: from mga17.intel.com ([192.55.52.151]:38294 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726675AbgERDqv (ORCPT ); Sun, 17 May 2020 23:46:51 -0400 IronPort-SDR: ZH6oqbVUoGtmCuMx+UoxT0UauaZ/vADgKTGwl4iOoq4USnge1gJQMKbdKgTBv/ugz5cWzwiP9u 11RnjRmMIT8g== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 May 2020 20:46:36 -0700 IronPort-SDR: 5xaNnBXdyt8r0qf/zMZd/YVJc6OU/S5Vhn820g7rDW7buiwZk83M0xgWdBeDOJniQGs8Xh9CTU 5x9asrT46bFQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,405,1583222400"; d="scan'208";a="373255165" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by fmsmga001.fm.intel.com with ESMTP; 17 May 2020 20:46:30 -0700 Date: Sun, 17 May 2020 23:36:41 -0400 From: Yan Zhao To: Xiang Zheng Cc: Kirti Wankhede , alex.williamson@redhat.com, cjia@nvidia.com, kevin.tian@intel.com, ziye.yang@intel.com, changpeng.liu@intel.com, yi.l.liu@intel.com, mlevitsk@redhat.com, eskultet@redhat.com, cohuck@redhat.com, dgilbert@redhat.com, jonathan.davies@nutanix.com, eauger@redhat.com, aik@ozlabs.ru, pasic@linux.ibm.com, felipe@nutanix.com, Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com, Ken.Xue@amd.com, zhi.a.wang@intel.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, Wang Haibin , prime.zeng@hisilicon.com Subject: Re: [PATCH Kernel v21 0/8] Add UAPIs to support migration for VFIO devices Message-ID: <20200518033641.GA14737@joy-OptiPlex-7040> Reply-To: Yan Zhao References: <1589577203-20640-1-git-send-email-kwankhede@nvidia.com> <689be011-4de4-6bfb-f2bb-8bb98046b9cb@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <689be011-4de4-6bfb-f2bb-8bb98046b9cb@huawei.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, May 18, 2020 at 10:39:52AM +0800, Xiang Zheng wrote: > Hi Kirti and Yan, > > How can I test this patch series on my SR-IOV devices? > I have looked through Yan's pathes for i40e VF live migration support： > https://patchwork.kernel.org/patch/11375177/ > I just updated the patches to v4. https://patchwork.kernel.org/cover/11554617/. It's based on v17 kernel + v16 qemu with some minor changes in qemu. > However, I cannot find the detailed implementation about device state > saving/restoring and dirty page logging. Has i40e hardware already supported > these two features? > In v4, vendor driver for i40e vf reports dirty pages to vfio container. the detailed implementation of identifying dirty pages and device state is not sent yet for process reason. We use a software way to get dirty pages i.e. dynamically trapping of BAR 0. Thanks Yan > And if once a device supports both features, how to implement live > migration for this device via this series patch? > > On 2020/5/16 5:13, Kirti Wankhede wrote: > > Hi, > > > > This patch set adds: > > * IOCTL VFIO_IOMMU_DIRTY_PAGES to get dirty pages bitmap with > > respect to IOMMU container rather than per device. All pages pinned by > > vendor driver through vfio_pin_pages external API has to be marked as > > dirty during migration. When IOMMU capable device is present in the > > container and all pages are pinned and mapped, then all pages are marked > > dirty. > > When there are CPU writes, CPU dirty page tracking can identify dirtied > > pages, but any page pinned by vendor driver can also be written by > > device. As of now there is no device which has hardware support for > > dirty page tracking. So all pages which are pinned should be considered > > as dirty. > > This ioctl is also used to start/stop dirty pages tracking for pinned and > > unpinned pages while migration is active. > > > > * Updated IOCTL VFIO_IOMMU_UNMAP_DMA to get dirty pages bitmap before > > unmapping IO virtual address range. > > With vIOMMU, during pre-copy phase of migration, while CPUs are still > > running, IO virtual address unmap can happen while device still keeping > > reference of guest pfns. Those pages should be reported as dirty before > > unmap, so that VFIO user space application can copy content of those > > pages from source to destination. > > > > * Patch 8 detect if IOMMU capable device driver is smart to report pages > > to be marked dirty by pinning pages using vfio_pin_pages() API. > > > > > > Yet TODO: > > Since there is no device which has hardware support for system memmory > > dirty bitmap tracking, right now there is no other API from vendor driver > > to VFIO IOMMU module to report dirty pages. In future, when such hardware > > support will be implemented, an API will be required such that vendor > > driver could report dirty pages to VFIO module during migration phases. > > > > Adding revision history from previous QEMU patch set to understand KABI > > changes done till now > > > > v20 -> v21 > > - Added checkin for GET_BITMAP ioctl for vfio_dma boundaries. > > - Updated unmap ioctl function - as suggested by Alex. > > - Updated comments in DIRTY_TRACKING ioctl definition - as suggested by > > Cornelia. > > > > v19 -> v20 > > - Fixed ioctl to get dirty bitmap to get bitmap of multiple vfio_dmas > > - Fixed unmap ioctl to get dirty bitmap of multiple vfio_dmas. > > - Removed flag definition from migration capability. > > > > v18 -> v19 > > - Updated migration capability with supported page sizes bitmap for dirty > > page tracking and maximum bitmap size supported by kernel module. > > - Added patch to calculate and cache pgsize_bitmap when iommu->domain_list > > is updated. > > - Removed extra buffers added in previous version for bitmap manipulation > > and optimised the code. > > > > v17 -> v18 > > - Add migration capability to the capability chain for VFIO_IOMMU_GET_INFO > > ioctl > > - Updated UMAP_DMA ioctl to return bitmap of multiple vfio_dma > > > > v16 -> v17 > > - Fixed errors reported by kbuild test robot on i386 > > > > v15 -> v16 > > - Minor edits and nit picks (Auger Eric) > > - On copying bitmap to user, re-populated bitmap only for pinned pages, > > excluding unmapped pages and CPU dirtied pages. > > - Patches are on tag: next-20200318 and 1-3 patches from Yan's series > > https://lkml.org/lkml/2020/3/12/1255 > > > > v14 -> v15 > > - Minor edits and nit picks. > > - In the verification of user allocated bitmap memory, added check of > > maximum size. > > - Patches are on tag: next-20200318 and 1-3 patches from Yan's series > > https://lkml.org/lkml/2020/3/12/1255 > > > > v13 -> v14 > > - Added struct vfio_bitmap to kabi. updated structure > > vfio_iommu_type1_dirty_bitmap_get and vfio_iommu_type1_dma_unmap. > > - All small changes suggested by Alex. > > - Patches are on tag: next-20200318 and 1-3 patches from Yan's series > > https://lkml.org/lkml/2020/3/12/1255 > > > > v12 -> v13 > > - Changed bitmap allocation in vfio_iommu_type1 to per vfio_dma > > - Changed VFIO_IOMMU_DIRTY_PAGES ioctl behaviour to be per vfio_dma range. > > - Changed vfio_iommu_type1_dirty_bitmap structure to have separate data > > field. > > > > v11 -> v12 > > - Changed bitmap allocation in vfio_iommu_type1. > > - Remove atomicity of ref_count. > > - Updated comments for migration device state structure about error > > reporting. > > - Nit picks from v11 reviews > > > > v10 -> v11 > > - Fix pin pages API to free vpfn if it is marked as unpinned tracking page. > > - Added proposal to detect if IOMMU capable device calls external pin pages > > API to mark pages dirty. > > - Nit picks from v10 reviews > > > > v9 -> v10: > > - Updated existing VFIO_IOMMU_UNMAP_DMA ioctl to get dirty pages bitmap > > during unmap while migration is active > > - Added flag in VFIO_IOMMU_GET_INFO to indicate driver support dirty page > > tracking. > > - If iommu_mapped, mark all pages dirty. > > - Added unpinned pages tracking while migration is active. > > - Updated comments for migration device state structure with bit > > combination table and state transition details. > > > > v8 -> v9: > > - Split patch set in 2 sets, Kernel and QEMU. > > - Dirty pages bitmap is queried from IOMMU container rather than from > > vendor driver for per device. Added 2 ioctls to achieve this. > > > > v7 -> v8: > > - Updated comments for KABI > > - Added BAR address validation check during PCI device's config space load > > as suggested by Dr. David Alan Gilbert. > > - Changed vfio_migration_set_state() to set or clear device state flags. > > - Some nit fixes. > > > > v6 -> v7: > > - Fix build failures. > > > > v5 -> v6: > > - Fix build failure. > > > > v4 -> v5: > > - Added decriptive comment about the sequence of access of members of > > structure vfio_device_migration_info to be followed based on Alex's > > suggestion > > - Updated get dirty pages sequence. > > - As per Cornelia Huck's suggestion, added callbacks to VFIODeviceOps to > > get_object, save_config and load_config. > > - Fixed multiple nit picks. > > - Tested live migration with multiple vfio device assigned to a VM. > > > > v3 -> v4: > > - Added one more bit for _RESUMING flag to be set explicitly. > > - data_offset field is read-only for user space application. > > - data_size is read for every iteration before reading data from migration, > > that is removed assumption that data will be till end of migration > > region. > > - If vendor driver supports mappable sparsed region, map those region > > during setup state of save/load, similarly unmap those from cleanup > > routines. > > - Handles race condition that causes data corruption in migration region > > during save device state by adding mutex and serialiaing save_buffer and > > get_dirty_pages routines. > > - Skip called get_dirty_pages routine for mapped MMIO region of device. > > - Added trace events. > > - Split into multiple functional patches. > > > > v2 -> v3: > > - Removed enum of VFIO device states. Defined VFIO device state with 2 > > bits. > > - Re-structured vfio_device_migration_info to keep it minimal and defined > > action on read and write access on its members. > > > > v1 -> v2: > > - Defined MIGRATION region type and sub-type which should be used with > > region type capability. > > - Re-structured vfio_device_migration_info. This structure will be placed > > at 0th offset of migration region. > > - Replaced ioctl with read/write for trapped part of migration region. > > - Added both type of access support, trapped or mmapped, for data section > > of the region. > > - Moved PCI device functions to pci file. > > - Added iteration to get dirty page bitmap until bitmap for all requested > > pages are copied. > > > > Thanks, > > Kirti > > > > > > > > Kirti Wankhede (8): > > vfio: UAPI for migration interface for device state > > vfio iommu: Remove atomicity of ref_count of pinned pages > > vfio iommu: Cache pgsize_bitmap in struct vfio_iommu > > vfio iommu: Add ioctl definition for dirty pages tracking > > vfio iommu: Implementation of ioctl for dirty pages tracking > > vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap > > vfio iommu: Add migration capability to report supported features > > vfio: Selective dirty page tracking if IOMMU backed device pins pages > > > > drivers/vfio/vfio.c | 13 +- > > drivers/vfio/vfio_iommu_type1.c | 569 ++++++++++++++++++++++++++++++++++++---- > > include/linux/vfio.h | 4 +- > > include/uapi/linux/vfio.h | 315 ++++++++++++++++++++++ > > 4 files changed, 842 insertions(+), 59 deletions(-) > > > > -- > Thanks, > Xiang >