[illumos-Developer] override read capacity response?

[Gordon Ross]

I have an illumos (oi-151) system running as a guest VM under Hyper-V
(the Win2008r2 hypervisor).  All is well with the usual virtual disks, but I
also have a physical disk I'd like to attach to one of my guests. When I do,
the guest sees the disk, but I get these complaints from cmlb:

Jul 25 15:35:07 vm40 cmlb: [ID 107833 kern.warning] WARNING:
/pci at 0,0/pci-ide at 7,1/ide at 0/cmdk at 1,0 (cmdk1):
Jul 25 15:35:07 vm40   Corrupt label - bad geometry
Jul 25 15:35:07 vm40 cmlb: [ID 107833 kern.notice]     Label says
976752000 blocks; Drive says 267378048 blocks

I just want to import some data from this disk, so I don't mind some sort of
temporary hack.  Is there a way to override the capacity cmdk reports?
I was looking at /kernel/drv/cmdk.conf and "nblocks" but I could use an
example of the syntax.

Thanks,
Gordon