On Mon, Jan 26, 2015 at 04:43:17AM -0800, Rodrigo Vivi wrote:
> From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> We don't need to incur the overhead of checking whether the object is
> pinned prior to changing its madvise. If the object is pinned, the
> madvise will not take effect until it is unpinned and so we cannot free
> the pages being pointed at by hardware. Marking a pinned object with
> allocated pages as DONTNEED will not trigger any undue warnings. The check
> is therefore superfluous, and by removing it we can remove a linear walk
> over all the vma the object has.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
I'd still would like to see some igt testcase which marks a pinned scanout
buffer asl DONTNEED. Just to make sure we don't accidentally create a gap
somewhere for a CVE to sneak through.
-Daniel
> ---
> drivers/gpu/drm/i915/i915_gem.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 6c40365..123ce34 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4365,11 +4365,6 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
> goto unlock;
> }
>
> - if (i915_gem_obj_is_pinned(obj)) {
> - ret = -EINVAL;
> - goto out;
> - }
> -
> if (obj->pages &&
> obj->tiling_mode != I915_TILING_NONE &&
> dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
> @@ -4388,7 +4383,6 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
>
> args->retained = obj->madv != __I915_MADV_PURGED;
>
> -out:
> drm_gem_object_unreference(&obj->base);
> unlock:
> mutex_unlock(&dev->struct_mutex);
> --
> 1.9.3
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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