[RFC PATCH 0/3] vfio/migration: Support manual clear vfio dirty log

[Kunkun Jiang]

In the past, we clear dirty log immediately after sync dirty log to
userspace. This may cause redundant dirty handling if userspace
handles dirty log iteratively:

After vfio clears dirty log, new dirty log starts to generate. These
new dirty log will be reported to userspace even if they are generated
before userspace handles the same dirty page.

Since a new dirty log tracking method for vfio based on iommu hwdbm[1]
has been introduced in the kernel and added a new capability named
VFIO_DIRTY_LOG_MANUAL_CLEAR, we can eliminate some redundant dirty
handling by supporting it.

This series include patches as below:
Patch 1:
- updated the linux-headers/linux/vfio.h from kernel side

Patch 2:
- introduced 'struct VFIODMARange' to describe a range of the given DMA
  mapping and with respect to a VFIO_IOMMU_MAP_DMA operation

Patch 3:
- implemented the operation to manual clear vfio dirty log, which can
  eliminate some redundant dirty handling

History:
v1 -> v2:
- Add a new ioctl VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP_NOCLEAR to get
  vfio dirty log when support manual clear.

Thanks,
Kunkun Jiang

[1]
IOMMU part: 
https://lore.kernel.org/linux-iommu/20210507102211.8836-1-zhukeqian1@huawei.com/
VFIO part: 
https://lore.kernel.org/kvm/20210507103608.39440-1-zhukeqian1@huawei.com/

Zenghui Yu (3):
  linux-headers: update against 5.12 and "manual clear vfio dirty log"
    series
  vfio: Maintain DMA mapping range for the container
  vfio/migration: Add support for manual clear vfio dirty log

 hw/vfio/common.c              | 211 ++++++++++++++++++++++++++++++++--
 include/hw/vfio/vfio-common.h |  10 ++
 linux-headers/linux/vfio.h    |  61 +++++++++-
 3 files changed, 273 insertions(+), 9 deletions(-)

-- 
2.23.0