[Openib-windows] Windows DMA model

[Fab Tillier]

> From: Jan Bottorff [mailto:jbottorff at xsigo.com]
> Sent: Tuesday, October 18, 2005 3:29 PM
> 
> >The SMI/GSI currently just call MmGetPhysicalAddress for MAD buffers,
> >and this is due to change, either by allocating MADs from a common
> >buffer or by doing DMA mappings when the MADs get posted to the QP
> >(likely the latter).
> 
> So what your saying is currently, the IB driver does NOT assure correct
> bus to processor physical address translation, and does NOT assure cache
> coherency on systems that need software help for maintaining cache
> coherency.

For MAD traffic and user-mode, that's exactly what I'm saying.  For IPoIB and
SRP, correct mappings and cache coherency is provided by the respective port
drivers.

Do any x86 or x64 systems need software help in this regard?  Do Itanium systems
(I assume they do, but don't know)?

> I aksed Microsoft about just calling MmGetPhysicalAddress for DMA and
> they responded:

You pasted the wrong response.

Thanks,

- Fab