[RFC PATCH 0/2] dm-crypt support for per-sector NVMe metadata

[Mikulas Patocka]

Hi

Some NVMe devices may be formatted with extra 64 bytes of metadata per 
sector.

Here I'm submitting for review dm-crypt patches that make it possible to 
use per-sector metadata for authenticated encryption. With these patches, 
dm-crypt can run directly on the top of a NVMe device, without using 
dm-integrity. These patches increase write throughput twice, because there 
is no write to the dm-integrity journal.

An example how to use it (so far, there is no support in the userspace 
cryptsetup tool):

# nvme format /dev/nvme1 -n 1 -lbaf=4
# dmsetup create cr --table '0 1048576 crypt 
capi:authenc(hmac(sha256),cbc(aes))-essiv:sha256 
01b11af6b55f76424fd53fb66667c301466b2eeaf0f39fd36d26e7fc4f52ade2de4228e996f5ae2fe817ce178e77079d28e4baaebffbcd3e16ae4f36ef217298 
0 /dev/nvme1n1 0 2 integrity:32:aead sector_size:4096'

Please review it - I'd like to know whether detecting the presence of 
per-sector metadata in crypt_integrity_ctr is correct whether it should be 
done differently.

Mikulas