Re: [PATCH v9 08/12] hw/block/nvme: Support Zoned Namespace Command Set

[Klaus Jensen]

On Nov 17 16:32, Keith Busch wrote:
> On Thu, Nov 12, 2020 at 08:36:39PM +0100, Klaus Jensen wrote:
> > On Nov  5 11:53, Dmitry Fomichev wrote:
> > > @@ -133,6 +300,12 @@ static Property nvme_ns_props[] = {
> > >      DEFINE_BLOCK_PROPERTIES(NvmeNamespace, blkconf),
> > >      DEFINE_PROP_UINT32("nsid", NvmeNamespace, params.nsid, 0),
> > >      DEFINE_PROP_UUID("uuid", NvmeNamespace, params.uuid),
> > > +    DEFINE_PROP_BOOL("zoned", NvmeNamespace, params.zoned, false),
> > 
> > I disagree on this. Using the "magic" value ensures that only one
> > command set can be selected. We can do a custom property so we can set
> > `iocs=zoned` as well as `iocs=0x2` if that makes it more user friendly?
> 
> IMO, 'iocs' is a rather difficult parameter name for a user to remember
> compared to 'zoned=true'. While 'iocs' is a spec field, the spec isn't
> very user friendly either, and these user parameters can hide the spec
> terms behind human comprehensible names.
> 

I'm okay with a "zoned" bool parameter and having zone size and capacity
in bytes. But parameters such as ZASL, MAR and MOR are "expert"
parameters so I think its better to use the spec field names and
meanings for those. The nvme device already has precedence for using
spec field names (and meanings, e.g. zeroes based) for "expert"
parameters (mdts, aerl).

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