[sldev] How Far For Security?

[Argent Stonecutter]

On 2008-06-22, at 01:32, Strife Onizuka wrote:
> You couldn't go straight from disk to GPU. There is no interface that
> connects the GPU to the disk. What you would do is write your program
> to make the appropriate requests to read a file into memory. The disk
> drive would be told where to read, and to use DMA to write the data
> directly to an already allocated memory range (the North Bridge would
> route the incoming data straight to memory).

I'm not asking "does the hardware exist", I'm asking "does the OS API  
exist"? You have to make zero-copy transfers to memory at specific  
*physical* addresses, bypassing the ubiquitous buffer cache which  
*is* handled by the CPU.

This kind of thing normally requires at the least privileged access,  
and probably kernel access, on any OS that makes even the slightest  
effort of implementing multiuser protection. Does Windows really  
allow non-privileged processes to grovel around in memory maps?