Re: [PATCH v2] nfit: add Hyper-V NVDIMM DSM command set to white list

[Dan Williams]

On Fri, Feb 1, 2019 at 7:32 PM Dexuan Cui <decui@xxxxxxxxxxxxx> wrote:
>
> > From: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Sent: Friday, February 1, 2019 5:29 PM
> > ...
> > Honestly, the quickest path to something functional for Linux is to
> > simply delete the _LSR support and use raw mode defined namespaces.
> > Why have labels if they are read-only and the region is sufficient for
> > defining boundaries?
> Hyper-V Virtual NVDIMM can already work with Ubuntu 19.04 virtual machine
> running on Hyper-V, i.e. I can create a raw or fsdax namesapce, and create a
> xfs or ext4 file sysetm in /dev/pmem0p1, and mount the file system with and
> without "-o dax". The basic functionality is good.

Only in label-less mode apparently.

> My recent work is mainly for ndctl support, i.e. get the health info by ndctl,
> and use ndctl to monitor the error events (if applicable).

Right, but the recent fixes have exposed Linux to a labelled namespace
implementation that violates some of the driver's basic assumptions.

To preserve the level of operation you're currently seeing Linux might
need to add a hyper-v-specific quirk to force label-less operation.