[ofw] RE: winmad installation

[Sean Hefty]

>Thanks for the prompt response.
>The call path goes from libibverbs ->
>winverbs.dll -> winverbs.sys -> hca driver
>
>May I ask you to explain a little more about the path from winverbs.sys -> hca
>driver ?
>(1) Is it an upper filter driver above HCA driver  getting driver interface via
>guid ?

Yes - winverbs.sys loads as an upper filter driver.  It obtains the HCA
interface directly through a query interface call.  For the 2.0 release, the HCA
drivers were modified to support multiple users, versus just ibal.

>(2) Since your path indicates its all at kernel level, I believe it's a direct
>verbs interface at kernel level and we do not need any user mode verbs library.

winverbs.sys only provides an IOCTL interface.  I guess any kernel driver could
query the HCA directly for its interface and use it.  The interface exported by
the HCA drivers is listed in iba/ib_ci.h, which is just a verbs interface.  The
other interface used by winverbs.sys is in ib_cm_ifc.h

- Sean