On Thu, Sep 27, 2012 at 09:27:57AM +0100, Chris Wilson wrote:
> As SandyBridge returns garbage when decoding certain addresses through
> the GTT (all memory below 1MiB and a very small number of individual
> pages) we need to prevent the GPU from utilizing those pages. The
> ultimate goal would be to prevent our allocator from handing us those
> pages, but that is a longer term project. In the short term, we can
> detect when we attempt to bind those pages to the GPU and return an
> error to the application rather than hang the GPU and potentially the
> system.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_gem_gtt.c | 40 ++++++++++++++++++++++++++++++++---
> 1 file changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index d9d3fc7..5c7ccfd 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -306,17 +306,51 @@ void i915_gem_restore_gtt_mappings(struct drm_device *dev)
> intel_gtt_chipset_flush();
> }
>
> +static bool
> +gen6_valid_addresses(struct drm_i915_gem_object *obj)
> +{
> + struct scatterlist *sg;
> + int i;
> +
> + for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) {
> + dma_addr_t addr = sg_dma_address(sg);
> + if (WARN(addr < 0x100000 ||
> + addr == 0x20050000 ||
> + addr == 0x20110000 ||
> + addr == 0x20130000 ||
> + addr == 0x20138000 ||
> + addr == 0x40004000,
> + "object references unaddressable physical pages: addr=%x",
> + (u32)addr))
> + return false;
Iirc the bug is about the physical address, no the remapped one after
dmar. We'd need to check the windows code for that though ...
-Daniel
> + }
> +
> + return true;
> +}
> +
> int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
> {
> - if (obj->has_dma_mapping)
> - return 0;
> + int ret;
>
> - if (!dma_map_sg(&obj->base.dev->pdev->dev,
> + if (!obj->has_dma_mapping &&
> + !dma_map_sg(&obj->base.dev->pdev->dev,
> obj->pages->sgl, obj->pages->nents,
> PCI_DMA_BIDIRECTIONAL))
> return -ENOSPC;
>
> + if (IS_GEN6(obj->base.dev) && !gen6_valid_addresses(obj)) {
> + ret = -EFAULT;
> + goto unmap;
> + }
> +
> return 0;
> +
> +unmap:
> + if (!obj->has_dma_mapping)
> + dma_unmap_sg(&obj->base.dev->pdev->dev,
> + obj->pages->sgl, obj->pages->nents,
> + PCI_DMA_BIDIRECTIONAL);
> + return ret;
> }
>
> void i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj,
> --
> 1.7.10.4
>
> _______________________________________________
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> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
