RE: [PATCH V2 0/2] nvme: Support user mode processing of ZNS Zone Changed AEN

[Clay Mayers <Clay.Mayers@kioxia.com>]

> From: Chaitanya Kulkarni <chaitanyak@nvidia.com>
> Sent: Monday, October 3, 2022 6:49 PM
> Subject: Re: [PATCH V2 0/2] nvme: Support user mode processing of ZNS Zone
> Changed AEN
> 
> On 9/29/22 15:39, clay.mayers@kioxia.com wrote:
> > From: Clay Mayers <clay.mayers@kioxia.com>
> >
> > This adds support for the ZNS Zone-Descriptor-Changes AEN, which is of
> > type notify and uses CQE.DW1 to convey the NSID of the log page to read.
> >
> > Patch 1 adds non-zero NVME_AEN_DATA with the value of CQE.DW1 to all
> > NVME_AEN uevents.
> >
> > Patch 2 generates a uevent for all unhandled AEN notify results instead
> > of issuing a dev warning.
> >
> > This support is planned to be used by both zone based applications and
> > another unreleased device with an alternate command set.
> >
> >
> 
> Please write a testcase in the blktest to this will get tested every
> release.
> 
> -ck

Ok - I'll give it a go to implement that but AENs by definition aren't a
response to a request (mostly) - they just happen.  The case that I know
of that creates a zone excursion AEN takes many hours to manifest and
that duration would be FLASH-type specific.  I don't know how you could
use a real device.

This patch was tested under QEMU with our custom emulator.  The
current QEMU NVMe/ZNS device doesn't emulate zone excursions so I'll
have to start there unless someone knows of a better way.