Hi all, Since the SMMUv3's nested translation stages[1] has been introduced by Eric, we need to pay attention to the migration of VFIO PCI devices in SMMUv3 nested stage mode. At present, it is not yet supported in QEMU. There are two problems in the existing framework.
First, the current way to get dirty pages is not applicable to nested stage mode. Because of the "Caching Mode", VTD can map the RAM through the host single stage (giova->hpa). "vfio_listener_log_sync" gets dirty pages by transferring "giova" to the kernel for the RAM block section of mapped MMIO region. In nested stage mode, we setup the stage 2 (gpa->hpa) and the stage 1(giova->gpa) separately. So it is inapplicable to get dirty pages by the current way in nested stage mode. Second, it also need to pass stage 1 configurations to the destination host after the migration. In Eric's patch, it passes the stage 1 configuration to the host on each STE update for the devices set the PASID PciOps. The configuration will be applied at physical level. But the data of physical level will not be sent to the destination host. So we have to pass stage 1 configurations to the destination host after the migration. Best Regards, Kunkun Jiang [1] [RFC,v8,00/28] vSMMUv3/pSMMUv3 2 stage VFIO integration http://patchwork.ozlabs.org/project/qemu-devel/cover/20210225105233.650545-1-eric.au...@redhat.com/ This Patch set includes patches as below: Patch 1-2: - Refactor the vfio_listener_log_sync and added a new function to get dirty pages in nested stage mode. Patch 3: - Added global_log_start/stop interface in vfio_memory_prereg_listener Patch 4: - Added the post_load function to vmstate_smmuv3 for passing stage 1 configuration to the destination host after the migration. History: v1 -> v2: - Add global_log_start/stop interface in vfio_memory_prereg_listener - Add support for repass stage 1 configs with multiple CDs to the host Kunkun Jiang (4): vfio: Introduce helpers to mark dirty pages of a RAM section vfio: Add vfio_prereg_listener_log_sync in nested stage vfio: Add vfio_prereg_listener_global_log_start/stop in nested stage hw/arm/smmuv3: Post-load stage 1 configurations to the host hw/arm/smmuv3.c | 62 +++++++++++++++++++++++++++++++++++++++ hw/arm/trace-events | 1 + hw/vfio/common.c | 71 ++++++++++++++++++++++++++++++++++++++++----- 3 files changed, 126 insertions(+), 8 deletions(-) -- 2.23.0
