Thank you very much, Kirti and Yan! On 2020/5/18 11:36, Yan Zhao wrote: > 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. Sounds interesting, is the dirty pages tracking done in the VM's vf driver or in the host's vf-migration module? It seems done in the host side, but I still cannot understand how dynamically trapping of BAR 0 can track the dirty pages. > > 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 <lkp@xxxxxxxxx> 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 >> > > . > -- Thanks, Xiang
