Summary This series RFC would like to introduce the live migration capability to vfio_mdev device.
As currently vfio_mdev device don't support migration, we introduce a device flag VFIO_DEVICE_FLAGS_MIGRATABLE to help determine whether the mdev device can be migrate or not, it will check the flag during the device initialization and decide to init the new vfio region VFIO_PCI_DEVICE_STATE_REGION_INDEX. The intention to add the new region is using it for vfio_mdev device status save and restore during the migration. The access to this region will be trapped and forward to the vfio_mdev device driver. There is an alternative way to achieve it is to add a new vfio ioctl to help fetch and save the device status. Also this series include two new vfio ioctl #define VFIO_DEVICE_PCI_STATUS_SET _IO(VFIO_TYPE, VFIO_BASE + 14) #define VFIO_DEVICE_PCI_GET_DIRTY_BITMAP _IO(VFIO_TYPE, VFIO_BASE + 15) The first one is used to contorl the device running status, we want to stop the mdev device before quary the status from its device driver and restart the device after migration. The second one is used to do the mdev device dirty page synchronization. So the vfio_mdev device migration sequence would be Source VM side: start migration | V get the cpu state change callback use status set ioctl to stop the mdev device | V save the deivce status into Qemufile which is read from the new vfio device status region | V quary the dirty page bitmap from deivce and add into qemu dirty list for sync Target VM side: restore the mdev device after get the saved status context from Qemufile | V get the cpu state change callback use status set ioctl to start the mdev device to put it in running status | V finish migration Yulei Zhang (5): vfio: introduce a new VFIO region for migration support vfio: Add struct vfio_vmstate_info to introduce vfio device put/get funtion vfio: introduce new VFIO ioctl VFIO_DEVICE_PCI_STATUS_SET vfio: use vfio_device_put/vfio_device_get for device status save/restore vifo: introduce new VFIO ioctl VFIO_DEVICE_PCI_GET_DIRTY_BITMAP hw/vfio/pci.c | 204 ++++++++++++++++++++++++++++++++++++++++++++- hw/vfio/pci.h | 3 + linux-headers/linux/vfio.h | 34 +++++++- 3 files changed, 239 insertions(+), 2 deletions(-) -- 2.7.4