drm/xe/tests: Fix g2g_test_array indexing

The G2G KUnit test allocates a compact N×N
matrix sized by gt_count and verifies entries
using dense indices: idx = (j * gt_count) + i

The producer path currently computes idx using
gt->info.id. However, gt->info.id values
are not guaranteed to be contiguous.
For example, with gt_count=2 and IDs {0,3},
this formula produces indices beyond the
allocated range, causing mismatches and
potential out-of-bounds access.

Update the producer to map each GT to a dense
index in [0..gt_count-1] and compute:
    idx = (tx_dense * gt_count) + rx_dense

Additionally, introduce an event-based delay
in g2g_test_in_order() to ensure ordering
between sends.

v2: Add single helper function (Daniele)

v3: Modify comment (Daniele)

Signed-off-by: Pallavi Mishra <pallavi.mishra@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patch.msgid.link/20260129054722.2150674-1-pallavi.mishra@intel.com

diff --git a/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c b/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c
index 3b213fcae91667050130f178120b25ea4cdad31f..ea8ca03effa906ba15f3b9cfb6e6fb54eb3a6fd1 100644 (file)
--- a/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c
+++ b/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c
@@ -48,6 +48,38 @@ struct g2g_test_payload  {
        u32 seqno;
 };
 
+static int slot_index_from_gts(struct xe_gt *tx_gt, struct xe_gt *rx_gt)
+{
+       struct xe_device *xe = gt_to_xe(tx_gt);
+       int idx = 0, found = 0, id, tx_idx, rx_idx;
+       struct xe_gt *gt;
+       struct kunit *test = kunit_get_current_test();
+
+       for (id = 0; id < xe->info.tile_count * xe->info.max_gt_per_tile; id++) {
+               gt = xe_device_get_gt(xe, id);
+               if (!gt)
+                       continue;
+               if (gt == tx_gt) {
+                       tx_idx = idx;
+                       found++;
+               }
+               if (gt == rx_gt) {
+                       rx_idx = idx;
+                       found++;
+               }
+
+               if (found == 2)
+                       break;
+
+               idx++;
+       }
+
+       if (found != 2)
+               KUNIT_FAIL(test, "GT index not found");
+
+       return (tx_idx * xe->info.gt_count) + rx_idx;
+}
+
 static void g2g_test_send(struct kunit *test, struct xe_guc *guc,
                          u32 far_tile, u32 far_dev,
                          struct g2g_test_payload *payload)
@@ -163,7 +195,7 @@ int xe_guc_g2g_test_notification(struct xe_guc *guc, u32 *msg, u32 len)
                goto done;
        }
 
-       idx = (tx_gt->info.id * xe->info.gt_count) + rx_gt->info.id;
+       idx = slot_index_from_gts(tx_gt, rx_gt);
 
        if (xe->g2g_test_array[idx] != payload->seqno - 1) {
                xe_gt_err(rx_gt, "G2G: Seqno mismatch %d vs %d for %d:%d -> %d:%d!\n",
@@ -180,13 +212,17 @@ done:
        return ret;
 }
 
+#define G2G_WAIT_TIMEOUT_MS 100
+#define G2G_WAIT_POLL_MS 1
+
 /*
  * Send the given seqno from all GuCs to all other GuCs in tile/GT order
  */
 static void g2g_test_in_order(struct kunit *test, struct xe_device *xe, u32 seqno)
 {
        struct xe_gt *near_gt, *far_gt;
-       int i, j;
+       int i, j, waited;
+       u32 idx;
 
        for_each_gt(near_gt, xe, i) {
                u32 near_tile = gt_to_tile(near_gt)->id;
@@ -205,6 +241,27 @@ static void g2g_test_in_order(struct kunit *test, struct xe_device *xe, u32 seqn
                        payload.rx_dev = far_dev;
                        payload.rx_tile = far_tile;
                        payload.seqno = seqno;
+
+                       /* Calculate idx for event-based wait */
+                       idx = slot_index_from_gts(near_gt, far_gt);
+                       waited = 0;
+
+                       /*
+                        * Wait for previous seqno to be acknowledged before sending,
+                        * to avoid queuing too many back-to-back messages and
+                        * causing a test timeout. Actual correctness of message
+                        * will be checked later in xe_guc_g2g_test_notification()
+                        */
+                       while (xe->g2g_test_array[idx] != (seqno - 1)) {
+                               msleep(G2G_WAIT_POLL_MS);
+                               waited += G2G_WAIT_POLL_MS;
+                               if (waited >= G2G_WAIT_TIMEOUT_MS) {
+                                       kunit_info(test, "Timeout waiting! tx gt: %d, rx gt: %d\n",
+                                                  near_gt->info.id, far_gt->info.id);
+                                       break;
+                               }
+                       }
+
                        g2g_test_send(test, &near_gt->uc.guc, far_tile, far_dev, &payload);
                }
        }