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Sun, 17 May 2020 20:16:57 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Sun, 17 May 2020 20:18:14 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Sun, 17 May 2020 20:18:14 -0700 Received: from [10.40.103.94] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 18 May 2020 03:18:04 +0000 Subject: Re: [PATCH Kernel v21 0/8] Add UAPIs to support migration for VFIO devices To: Xiang Zheng , References: <1589577203-20640-1-git-send-email-kwankhede@nvidia.com> <689be011-4de4-6bfb-f2bb-8bb98046b9cb@huawei.com> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: Date: Mon, 18 May 2020 08:48:00 +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: <689be011-4de4-6bfb-f2bb-8bb98046b9cb@huawei.com> 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: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1589771817; bh=UjaixRgK+VgzjSZBMZoL6THdQ4iQ85fCXABC5EAKYl8=; 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=UQdienXom0Epgme1lNXL6T0viozZtlsCHOLy5sX6lcC4YzbC4ItjFoIMjsqwXVoi9 Ff21N/8YylOV+MVOdDxVRO3SpodH3Hi5PX0r5lxkq3FdPBVk2M4WD11ZoVMsZ0WhRZ H8oLziZEv4j14yjF6WvPn4+goeu0y0GGQ+3SdssCsKOHccHAH9sufuHpu2z+IL/FAU cJ0gs9NmMui+k8DjF0h74Yh4JkB+u/fsoetUyDpXlH9M3NGl3Hdy/CNMal7Jxr0vDr VbvxYK+kauWd8OtO6SKe6/JbR/XrfvSOPTtPS41o+pz1V2dh8wT+SZ1qnK4K4amyMk bpzao6ArXTOBQ== Received-SPF: pass client-ip=216.228.121.64; envelope-from=kwankhede@nvidia.com; helo=hqnvemgate25.nvidia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/17 23:18:14 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: cjia@nvidia.com, kvm@vger.kernel.org, aik@ozlabs.ru, Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, eauger@redhat.com, yi.l.liu@intel.com, eskultet@redhat.com, ziye.yang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, felipe@nutanix.com, Wang Haibin , zhi.a.wang@intel.com, kevin.tian@intel.com, dgilbert@redhat.com, alex.williamson@redhat.com, prime.zeng@hisilicon.com, changpeng.liu@intel.com, cohuck@redhat.com, Ken.Xue@amd.com, jonathan.davies@nutanix.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/18/2020 8:09 AM, Xiang Zheng wrote: > Hi Kirti and Yan, >=20 > 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=EF= =BC=9A > https://patchwork.kernel.org/patch/11375177/ > =09 > However, I cannot find the detailed implementation about device state > saving/restoring and dirty page logging. Details of device state transitions, how user application should use=20 UAPI and how vendor driver should behave are mentioned in the comment of=20 UAPI: https://lore.kernel.org/kvm/1589577203-20640-2-git-send-email-kwankhede@nvi= dia.com/ > Has i40e hardware already supported > these two features? >=20 > And if once a device supports both features, how to implement live > migration for this device via this series patch? >=20 Here is the patch-set which adds migration support to mtty sample=20 device, you can refer to see how to implement on driver side: https://lore.kernel.org/kvm/1588614860-16330-1-git-send-email-kwankhede@nvi= dia.com/ I'm working on preparing QEMU patches for v21 and will be sending out soon. Thanks, Kirti > 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 b= y >> 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 mar= ked >> dirty. >> When there are CPU writes, CPU dirty page tracking can identify dirti= ed >> 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 consider= ed >> 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 keepi= ng >> reference of guest pfns. Those pages should be reported as dirty befo= re >> 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 drive= r >> to VFIO IOMMU module to report dirty pages. In future, when such hardwar= e >> 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 dirt= y >> page tracking and maximum bitmap size supported by kernel module. >> - Added patch to calculate and cache pgsize_bitmap when iommu->domain_li= st >> is updated. >> - Removed extra buffers added in previous version for bitmap manipulatio= n >> and optimised the code. >> >> v17 -> v18 >> - Add migration capability to the capability chain for VFIO_IOMMU_GET_IN= FO >> 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 rang= e. >> - 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 pa= ge. >> - Added proposal to detect if IOMMU capable device calls external pin pa= ges >> 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 pag= e >> 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 lo= ad >> 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 migrati= on, >> 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 define= d >> 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 place= d >> 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 sectio= n >> of the region. >> - Moved PCI device functions to pci file. >> - Added iteration to get dirty page bitmap until bitmap for all requeste= d >> 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(-) >> >=20