Re: [PATCH 5/5] hw/nvme: flexible data placement emulation

[Keith Busch]

This mostly looks fine. I need to clarify some spec decisions, though.

By default, FDP feature is disabled: "The default value of this Feature shall
be 0h." You can't change the value as long as namespaces exist within the
group, so FDP requires NS Mgmt be supported if you're going to enable it. The
spec, however, doesn't seem to explicitly say that, and NS Mgmt isn't currently
supported in this controller.

We can look past that for this implementation to allow static settings even if
that doesn't perfectly align with this feature (NS Mgmt is kind of difficult
here). In order to match what the spec says is possible though, we can't have a
namespace with more than 128 placement handles since that's the most you can
provide when you create the namespace.

Does that make sense, or am I totally misunderstanding the details?