--- /dev/null
+From 85636167e3206c3fbd52254fc432991cc4e90194 Mon Sep 17 00:00:00 2001
+From: John Harrison <John.C.Harrison@Intel.com>
+Date: Wed, 15 Feb 2023 17:11:01 -0800
+Subject: drm/i915: Don't use BAR mappings for ring buffers with LLC
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: John Harrison <John.C.Harrison@Intel.com>
+
+commit 85636167e3206c3fbd52254fc432991cc4e90194 upstream.
+
+Direction from hardware is that ring buffers should never be mapped
+via the BAR on systems with LLC. There are too many caching pitfalls
+due to the way BAR accesses are routed. So it is safest to just not
+use it.
+
+Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
+Fixes: 9d80841ea4c9 ("drm/i915: Allow ringbuffers to be bound anywhere")
+Cc: Chris Wilson <chris@chris-wilson.co.uk>
+Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
+Cc: Jani Nikula <jani.nikula@linux.intel.com>
+Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
+Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
+Cc: intel-gfx@lists.freedesktop.org
+Cc: <stable@vger.kernel.org> # v4.9+
+Tested-by: Jouni Högander <jouni.hogander@intel.com>
+Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
+Link: https://patchwork.freedesktop.org/patch/msgid/20230216011101.1909009-3-John.C.Harrison@Intel.com
+(cherry picked from commit 65c08339db1ada87afd6cfe7db8e60bb4851d919)
+Signed-off-by: Jani Nikula <jani.nikula@intel.com>
+Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/gpu/drm/i915/gt/intel_ringbuffer.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/gpu/drm/i915/gt/intel_ringbuffer.c
++++ b/drivers/gpu/drm/i915/gt/intel_ringbuffer.c
+@@ -1208,7 +1208,7 @@ int intel_ring_pin(struct intel_ring *ri
+ if (unlikely(ret))
+ goto err_unpin;
+
+- if (i915_vma_is_map_and_fenceable(vma))
++ if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915))
+ addr = (void __force *)i915_vma_pin_iomap(vma);
+ else
+ addr = i915_gem_object_pin_map(vma->obj,
+@@ -1252,7 +1252,7 @@ void intel_ring_unpin(struct intel_ring
+ intel_ring_reset(ring, ring->emit);
+
+ i915_vma_unset_ggtt_write(vma);
+- if (i915_vma_is_map_and_fenceable(vma))
++ if (i915_vma_is_map_and_fenceable(vma) && !HAS_LLC(vma->vm->i915))
+ i915_vma_unpin_iomap(vma);
+ else
+ i915_gem_object_unpin_map(vma->obj);