Re: [Xen-devel] [PATCH RESEND] tools/libxl: add support for emulated NVMe drives

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

Paul Durrant writes ("RE: [PATCH RESEND] tools/libxl: add support for emulated 
NVMe drives"):
> > Oh, wait, I have just noticed that you have reused an entry in this
> > table!
> > 
> >        1 << 28 | disk << 8 | partition   xvd, disks or partitions 16 onwards
> > ...
> > > +    1 << 28 | disk << 8               nvme, all disks, whole disk only
> 
> Yes, that was intentional. No need for a new concrete encoding if we
> ignore namespaces, as I said in the commit comment. If you want to
> support namespaces then it would need something new... which doesn't
> seem worth it since QEMU has no support.

That's not my point.  The purpose of this table is to advise guests
what the conventional in-guest device name ought to be for a certain
vbd.

We can't have one single numerical encoding mapping to two device
names.  That makes no sense.

Presumably these NVME devices should be subject to the same vbd and
unplug approach as scsi and ide disks.  In which case guests need to
be told that the device name for the vbd should be "nvme<something>",
which can only be done by using a different number.

Ian.

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