Intel QAT Driver Preps Live Migration Support For Linux 6.10

Queued up recently into the crypto subsystem's development branch ahead of the Linux 6.10 merge window is support for VFIO live migration with Intel's QuickAssist Technology (QAT) driver.

Intel QAT can be very useful for accelerating compression and encryption with supported software and where having a QAT accelerator card or found within the QAT support on recent Xeon Scalable processors. This live migration support is about being able to handle guest virtual machines being migrated between nodes while retaining QAT support.

The newly-queued code allows for live migration of Intel QAT Gen4 SRIOV Virtual Functions (VFs). The QAT driver can save and restore the state of a bank to which a VF is encompassed. The Intel patch series explains:

Here are the steps required to test the live migration of a QAT GEN4 VF:
1. Bind one or more QAT GEN4 VF devices to the module qat_vfio_pci.ko

2. Assign the VFs to the virtual machine and enable device live migration

3. Run a workload using a QAT VF inside the VM, for example using qatlib

4. Migrate the VM from the source node to a destination node

The patches working out the live migration support for Intel QAT are queued in cryptodev-2.6.git ahead of the Linux 6.10 merge window opening next month.