On 04/15/2014 05:16 PM, Ian Romanick wrote: > On 04/15/2014 03:50 PM, Kenneth Graunke wrote: >> On 04/15/2014 10:08 AM, Mike Stroyan wrote: >>> I would go farther than requiring the returned bo->size to be covered by >>> backing pages. >>> There really should be backing pages for every page mapped by >>> drm_intel_gem_bo_map. >>> No mapped addresses should be affecting memory outside of an object's >>> backing pages. >>> >>> If tiling can result in access to unallocated memory it might even lead >>> to corruption of data in pages >>> used by different processes. That would break GL_ARB_robustness >>> requirements. >> >> It shouldn't, now that proper PPGTT support has landed in the kernel - >> only data belonging to a single process is mapped into its address >> space. So, a process can accidentally read or trash other portions of >> its own memory, but never any other memory. This seems acceptable, as >> it's how things work with normal CPU programs. > > It is fine... for now. GL_ARB_robust_buffer_access makes stronger > guarantees about out-of-buffer accesses. Reads outside a buffer (e.g., > accessing too large an array element for an array contained in a UBO) > can only return data from elsewhere in the buffer or zero. WebGL > implementers really want this. > > I don't think that's relevant here because the fences only apply to CPU > access, yeah?
Right. This shouldn't affect that.
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