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 <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 >
