Comparing pte index to a number of entries is wrong
when clearing a range of pte entries. Use end marker
of 'one past' to correctly point adequate number of
ptes to the scratch page.
Fixes: d209b9c3cd28 ("drm/i915/gtt: Split gen8_ppgtt_clear_pte_range")
References: https://bugs.freedesktop.org/show_bug.cgi?id=98282
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx>
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index e7afad5..cda263c 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -712,13 +712,13 @@ static int gen8_48b_mm_switch(struct i915_hw_ppgtt *ppgtt,
*/
static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm,
struct i915_page_table *pt,
- uint64_t start,
- uint64_t length)
+ const uint64_t start,
+ const uint64_t length)
{
struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
- unsigned int pte_start = gen8_pte_index(start);
- unsigned int num_entries = gen8_pte_count(start, length);
- uint64_t pte;
+ const unsigned int num_entries = gen8_pte_count(start, length);
+ unsigned int pte = gen8_pte_index(start);
+ unsigned int pte_end = pte + num_entries;
gen8_pte_t *pt_vaddr;
gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
I915_CACHE_LLC);
@@ -726,17 +726,20 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm,
if (WARN_ON(!px_page(pt)))
return false;
- bitmap_clear(pt->used_ptes, pte_start, num_entries);
+ bitmap_clear(pt->used_ptes, pte, num_entries);
if (bitmap_empty(pt->used_ptes, GEN8_PTES)) {
free_pt(vm->dev, pt);
return true;
}
+ if (WARN_ON_ONCE(pte_end > GEN8_PTES))
+ pte_end = GEN8_PTES;
+
pt_vaddr = kmap_px(pt);
- for (pte = pte_start; pte < num_entries; pte++)
- pt_vaddr[pte] = scratch_pte;
+ while (pte < pte_end)
+ pt_vaddr[pte++] = scratch_pte;
kunmap_px(ppgtt, pt_vaddr);
--
2.7.4
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