Re: [Intel-gfx] [PATCH v6 2/2] drm/i915: add guard page to ggtt->error_capture

2023-03-13 Thread Das, Nirmoy
On 3/10/2023 10:23 AM, Andrzej Hajda wrote: Write-combining memory allows speculative reads by CPU. ggtt->error_capture is WC mapped to CPU, so CPU/MMU can try to prefetch memory beyond the error_capture, ie it tries to read memory pointed by next PTE in GGTT. If this PTE points to invalid addr

[PATCH v6 2/2] drm/i915: add guard page to ggtt->error_capture

2023-03-10 Thread Andrzej Hajda
Write-combining memory allows speculative reads by CPU. ggtt->error_capture is WC mapped to CPU, so CPU/MMU can try to prefetch memory beyond the error_capture, ie it tries to read memory pointed by next PTE in GGTT. If this PTE points to invalid address DMAR errors will occur. This behaviour was o