Linux kernel (drivers/vfio/pci/hisilicon): The VFIO migration save and resume paths do not advance the data pointer by

Impact

The VFIO migration save and resume paths do not advance the data pointer by the file offset once PRE_COPY is in use, so device state is written to and read from the wrong place in the migration buffer. On the destination the device is restored from corrupted state and starts issuing bad DMA - the upstream log shows SMMU fault events and device queue timeouts. A passthrough device programmed from mis-indexed state is a device operating outside what the host thinks it authorised.

Who can reach it

The resume side parses the incoming migration stream, so the mis-indexed data comes from the migration source rather than from the tenant directly. Reached whenever a device is migrated with PRE_COPY enabled. Conditional on HiSilicon ACC accelerators (ZIP/SEC/HPRE) passed through with the hisi_acc_vfio_pci variant driver - not present on typical GPU fleets, though the pattern generalises to any variant driver's migration-state handling.

What to do

The record lists no fixed release; boot a kernel carrying the stable fix commits below. Interim control: disable live migration for hisi_acc passthrough devices, or disable the PRE_COPY phase, until patched.

References