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

[Dexuan Cui]

> From: Linux-nvdimm <linux-nvdimm-bounces@xxxxxxxxxxxx> On Behalf Of
> Dexuan Cui
> Sent: Friday, February 1, 2019 4:34 PM
> > > > ...
> > > > Those reads find a namespace index block
> > > > and a label. Unfortunately the label has the LOCAL flag set and Linux
> > > > explicitly ignores pmem namespace labels with that bit set. The reason
> > > > for that is due to the fact that the original definition of the LOCAL
> > > > bit from v1.1 of the namespace label implementation [1] explicitly
> > > > limited the LOCAL flag to "block aperture" regions. If you clear that
> > > > LOCAL flag I expect it will work. To my knowledge Windows pretends
> > > > that the v1.1 definition never existed.

On the libnvdimm-pending branch, I get this:

root@decui-gen2-u1904:~/nvdimm# ndctl list
root@decui-gen2-u1904:~/nvdimm# ndctl list --idle
[
  {
    "dev":"namespace1.0",
    "mode":"raw",
    "size":0,
    "uuid":"00000000-0000-0000-0000-000000000000",
    "state":"disabled"
  },
  {
    "dev":"namespace0.0",
    "mode":"raw",
    "size":0,
    "uuid":"00000000-0000-0000-0000-000000000000",
    "state":"disabled"
  }
]

With the patch that clears the LOCAL label (BTW, the initial value of flags is 0x3,
meaning a read-only local label) :
@@ -2496,6 +2500,7 @@ static int init_active_labels(struct nd_region *nd_region)
                        if (!label_ent)
                                break;
                        label = nd_label_active(ndd, j);
+                       label->flags &= ~NSLABEL_FLAG_LOCAL;
                        label_ent->label = label;

I get this:

root@decui-gen2-u1904:~/nvdimm# ndctl list
root@decui-gen2-u1904:~/nvdimm# ndctl list --idle
[
  {
    "dev":"namespace1.0",
    "mode":"raw",
    "size":0,
    "uuid":"c258aaab-f72b-e546-bfa5-be5e07761dbc",
    "state":"disabled",
    "name":"Microsoft Hyper-V NVDIMM 1 Label"
  },
  {
    "dev":"namespace0.0",
    "mode":"raw",
    "size":0,
    "uuid":"9f0497a7-4453-7c40-ad35-21a791e00345",
    "state":"disabled",
    "name":"Microsoft Hyper-V NVDIMM 0 Label"
  }
]

The "size" and "mode" still don't look right, but the improvement is that
now I can see a good descriptive "name", which I suppose is retrieved
from Hyper-V.

With Ubuntu 19.04 (4.18.0-11-generic), I get this:
(Note: the "mode" and "size" are correct. The "uuid" is different from
the above "9f0497a7-4453-7c40-ad35-21a791e00345" -- this is weird.) 

root@decui-gen2-u1904:~# ndctl list
[
  {
    "dev":"namespace1.0",
    "mode":"raw",
    "size":137438953472,
    "blockdev":"pmem1"
  },
  {
    "dev":"namespace0.0",
    "mode":"fsdax",
    "map":"dev",
    "size":33820770304,
    "uuid":"35018886-397e-4fe7-a348-0a4d16eec44d",
    "blockdev":"pmem0"
  }
]
 
I'm trying to find out the correct solution. I apprecite your insights!

Thanks,
-- Dexuan