[PATCH] drm/i915/guc: prevent a possible int overflow in wq offsets

[Nikita Zhandarovich]

It may be possible for the sum of the values derived from
i915_ggtt_offset() and __get_parent_scratch_offset()/
i915_ggtt_offset() to go over the u32 limit before being assigned
to wq offsets of u64 type.

Mitigate these issues by expanding one of the right operands
to u64 to avoid any overflow issues just in case.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 2584b3549f4c ("drm/i915/guc: Update to GuC version 70.1.1")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index 9400d0eb682b..908ebfa22933 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -2842,9 +2842,9 @@ static void prepare_context_registration_info_v70(struct intel_context *ce,
 		ce->parallel.guc.wqi_tail = 0;
 		ce->parallel.guc.wqi_head = 0;
 
-		wq_desc_offset = i915_ggtt_offset(ce->state) +
+		wq_desc_offset = (u64)i915_ggtt_offset(ce->state) +
 				 __get_parent_scratch_offset(ce);
-		wq_base_offset = i915_ggtt_offset(ce->state) +
+		wq_base_offset = (u64)i915_ggtt_offset(ce->state) +
 				 __get_wq_offset(ce);
 		info->wq_desc_lo = lower_32_bits(wq_desc_offset);
 		info->wq_desc_hi = upper_32_bits(wq_desc_offset);