Linux 6.1 Brings VirtIO Block "Secure Erase", vDPA Feature Provisioning

The VirtIO changes were merged this week for the Linux 6.1 merge window that is ending this weekend.

Notable with Linux 6.1 on the VirtIO front is that the block driver "virtio_blk" has introduced "SECURE ERASE" support. Secure Erase functionality was added to the VirtIO specification this year. VIRTIO_BLK_F_SECURE_ERASE mandates that beyond regular SSD "discard" functionality, all discarded blocks that were possibly created via garbage collection also must be erased. The underlying block/storage driver must in turn support this secure erase functionality for it to be exposed. With the VirtIO implementation, secure erase requests are passed on from the guest and to the actual back-end for carrying out the request.

The other main feature of the VirtIO updates for Linux 6.1 is supporting vDPA feature provisioning:

Virtio features are negotiated between the device and the drivers. This allows the mediation layer like vDPA to hide some features from the driver to faciliate the cross vendor live migration:

vDPA on the source supports feature set X
vDPA on the destination supports feature set Y

Management can simply provision the vDPA instance with features X&Y on both source and destination to let the vDPA can be migrate-able between the two vDPA devies with different features support.

This series tries to allow the device features to be provisioned via netlink to achieve this.

On the VirtIO networking side is also going along with the 9p changes in Linux 6.1 to allow for faster file sharing between hosts and guests.

See this pull request now in mainline Linux 6.1 for the complete set of VirtIO feature changes targeting this end-of-year 2022 kernel.