Hi Kirti: What kind of platform/IO are you using now to do the basic code verification? I just want to check if I can verify it on my platform, and if any open IO cards available? Thanks. Regards Zengtao > -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] > On Behalf Of Kirti Wankhede > Sent: Saturday, February 08, 2020 3:42 AM > To: alex.williamson@xxxxxxxxxx; cjia@xxxxxxxxxx > Cc: kevin.tian@xxxxxxxxx; ziye.yang@xxxxxxxxx; > changpeng.liu@xxxxxxxxx; yi.l.liu@xxxxxxxxx; mlevitsk@xxxxxxxxxx; > eskultet@xxxxxxxxxx; cohuck@xxxxxxxxxx; dgilbert@xxxxxxxxxx; > jonathan.davies@xxxxxxxxxxx; eauger@xxxxxxxxxx; aik@xxxxxxxxx; > pasic@xxxxxxxxxxxxx; felipe@xxxxxxxxxxx; > Zhengxiao.zx@xxxxxxxxxxxxxxx; shuangtai.tst@xxxxxxxxxxxxxxx; > Ken.Xue@xxxxxxx; zhi.a.wang@xxxxxxxxx; yan.y.zhao@xxxxxxxxx; > qemu-devel@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Kirti Wankhede > Subject: [PATCH v12 Kernel 0/7] KABIs to support migration for VFIO > devices > > Hi, > > This patch set adds: > * New 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 7 is proposed change to 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 > > 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 (7): > vfio: KABI for migration interface for device state > vfio iommu: Remove atomicity of ref_count of pinned pages > vfio iommu: Add ioctl definition for dirty pages tracking. > vfio iommu: Implementation of ioctl to for dirty pages tracking. > vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before > unmap > vfio iommu: Adds flag to indicate dirty pages tracking capability > support > vfio: Selective dirty page tracking if IOMMU backed device pins pages > > drivers/vfio/vfio.c | 13 +- > drivers/vfio/vfio_iommu_type1.c | 435 > +++++++++++++++++++++++++++++++++++++--- > include/linux/vfio.h | 4 +- > include/uapi/linux/vfio.h | 267 +++++++++++++++++++++++- > 4 files changed, 692 insertions(+), 27 deletions(-) > > -- > 2.7.0
