On Jan 24 08:01, Keith Busch wrote:

The NVM Express protocol added enhancements to the data integrity field
formats beyond the T10 defined protection information. A detailed
description of the new formats can be found in the NVMe's NVM Command
Set Specification, section 5.2, available at:

  https://nvmexpress.org/wp-content/uploads/NVM-Command-Set-Specification-1.0b-2021.12.18-Ratified.pdf

This series implements one possible new format: the CRC64 guard with
48-bit reference tags. This does not add support for the variable
"storage tag" field.

The NVMe CRC64 parameters (from Rocksoft) were not implemented in the
kernel, so a software implementation is included in this series based on
the generated table. This series does not include any possible hardware
excelleration (ex: x86's pclmulqdq), so it's not very high performant
right now.

Hi Keith,

Tested this on QEMU and (assuming we didnt implement the same bugs) it
looks good functionally for separate metadata. However, it should also
be able to support PRACT (i.e. pi strip/insert device-side) if
nvme_ns_has_pi() is updated to also match on the 16 byte pi tuple. I
made it work by just hitting it with a hammer and changing the
comparison to hard-coded 16 bytes, but it should of course handle both
cases.

Naveen and I will post the emulated implementation (that certainly isnt
very high performant either) on qemu-block ASAP if others are interested
in giving this a spin without having hardware available.