[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-devel] xen/arm: On chip memory mappings



Hi,

I'd like to support the assignment of on chip RAMs to guests, starting with 
dom0.

The mmio-sram compatible device kinda works already but the 2nd stage MMU
mapping is done with DEVICE memory attributes. This doesn't work well for
SRAMs for several reasons (e.g performance, alignment checks etc).

I guess we could add special treatment of these nodes to create Normal memory 
mappings.

The rules for combining the memory attributes from S1 and S2 translations
suggest that mapping things at S2 with Normal memory Inner/Outer WB cacheable
would give the guest/S1 flexibility in choosing the final attributes.
It seems to me like guest drivers have the best knowledge to decide how to
map the node memory regions.

Keeping the S2 shareability set to inner (like we already do for memory)
seems to be a good idea though.

So the question I had is, why do we map nodes at S2 with DEVICE attributes at 
all?
Am I missing something?

Thanks,
Edgar

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.