[Intel-gfx] [PATCH 29/33] drm/i915/gt: Track timeline GGTT offset separately from subpage offset

[Chris Wilson]

Quoting Chris Wilson (2020-11-13 09:41:24)
> Currently we know that the timeline status page is at most a page in
> size, and so we can preserve the lower 12bits of the offset when
> relocating the status page in the GGTT. If we want to use a larger
> object, such as the context state, we may not necessarily use a position
> within the first page and so need more than 12b.

Hmm, the ppHWSP is in the first page of the context state, but
previously we have allocated pages before the context image for private
use that would offset the ppHWSP over the 12b boundary.

Currently we are allocating pages after the context image for private
use (e.g. indirect context restores), maybe that trend will continue?
-Chris