Ian Molton wrote: > On Mon, 27 May 2002 15:01:47 -0600 > Jens Owen <[EMAIL PROTECTED]> wrote: > > >>1) We loosen security requirements for 3D drivers. This will allow >>far less data copying, memory mapping/unmapping and system calls. >>Many modern graphics chips can have their data managed completely in a >>user space AGP ring buffer removing the need to call the kernel module >>at all. The primary limitation that has kept us from persuing these >>implementations so far have been security holes with AGP blits. >> > > I dont pretend to understand everything here, but wouldnt it be more > secure, and STILL blindingly fast, to set up the data in userspace, and > trigger the AGP DMA / blits from kernel space with some bounds checking? > > surely 1 system call per DMA isnt that bad?
That's what we do for the cases where we can do so securely. All the vertex data on most cards takes this route. Some data can't go this way because the buffers are subject to attack after the checking has been performed but before they reach the hardware. Whether specific operations are vulnerable or not depends on the details of the card's dma engine. Keith _______________________________________________________________ Don't miss the 2002 Sprint PCS Application Developer's Conference August 25-28 in Las Vegas -- http://devcon.sprintpcs.com/adp/index.cfm _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
