[PATCH 4/4] drm/xe/guc: Add test for G2G communications

John.C.Harrison at Intel.com John.C.Harrison at Intel.com
Fri Jul 25 00:21:05 UTC 2025


From: John Harrison <John.C.Harrison at Intel.com>

Add a test for sending messages from every GuC to every other GuC to
test G2G communications.

Note that, being a debug only feature, the test interface only exists
in pre-production builds of the GuC firmware.

Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
---
 drivers/gpu/drm/xe/abi/guc_actions_abi.h    |   2 +
 drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c  | 759 ++++++++++++++++++++
 drivers/gpu/drm/xe/tests/xe_live_test_mod.c |   2 +
 drivers/gpu/drm/xe/xe_device_types.h        |   7 +
 drivers/gpu/drm/xe/xe_guc.c                 |   4 +
 drivers/gpu/drm/xe/xe_guc.h                 |   4 +
 drivers/gpu/drm/xe/xe_guc_ct.c              |   5 +
 drivers/gpu/drm/xe/xe_guc_fwif.h            |   1 +
 8 files changed, 784 insertions(+)
 create mode 100644 drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c

diff --git a/drivers/gpu/drm/xe/abi/guc_actions_abi.h b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
index 81eb046aeebf..0395998ca75c 100644
--- a/drivers/gpu/drm/xe/abi/guc_actions_abi.h
+++ b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
@@ -154,6 +154,8 @@ enum xe_guc_action {
 	XE_GUC_ACTION_NOTIFY_FLUSH_LOG_BUFFER_TO_FILE = 0x8003,
 	XE_GUC_ACTION_NOTIFY_CRASH_DUMP_POSTED = 0x8004,
 	XE_GUC_ACTION_NOTIFY_EXCEPTION = 0x8005,
+	XE_GUC_ACTION_TEST_G2G_SEND = 0xF001,
+	XE_GUC_ACTION_TEST_G2G_RECV = 0xF002,
 	XE_GUC_ACTION_LIMIT
 };
 
diff --git a/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c b/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c
new file mode 100644
index 000000000000..9bc8a43f7138
--- /dev/null
+++ b/drivers/gpu/drm/xe/tests/xe_guc_g2g_test.c
@@ -0,0 +1,759 @@
+// SPDX-License-Identifier: GPL-2.0 AND MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include <linux/delay.h>
+
+#include <kunit/test.h>
+#include <kunit/visibility.h>
+
+#include "tests/xe_kunit_helpers.h"
+#include "tests/xe_pci_test.h"
+#include "tests/xe_test.h"
+
+#include "xe_bo.h"
+#include "xe_device.h"
+#include "xe_pm.h"
+
+/*
+ * Payload is opaque to GuC. So KMD can define any structure or size it wants.
+ */
+struct g2g_test_payload  {
+	u32 tx_dev;
+	u32 tx_tile;
+	u32 rx_dev;
+	u32 rx_tile;
+	u32 seqno;
+};
+
+static void g2g_test_send(struct kunit *test, struct xe_guc *guc,
+			  u32 far_tile, u32 far_dev,
+			  struct g2g_test_payload *payload)
+{
+	struct xe_device *xe = guc_to_xe(guc);
+	struct xe_gt *gt = guc_to_gt(guc);
+	u32 *action, total;
+	size_t payload_len;
+	int ret;
+
+	payload_len = sizeof(*payload) / sizeof(u32);
+	KUNIT_ASSERT_EQ_MSG(test, sizeof(*payload), payload_len * sizeof(u32),
+			    "G2G payload not u32 aligned\n");
+
+	total = 4 + payload_len;
+	action = kunit_kmalloc_array(test, total, sizeof(*action), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, action);
+
+	action[0] = XE_GUC_ACTION_TEST_G2G_SEND;
+	action[1] = far_tile;
+	action[2] = far_dev;
+	action[3] = payload_len;
+	memcpy(action + 4, payload, payload_len * sizeof(u32));
+
+	atomic_inc(&xe->g2g_test_count);
+
+	/*
+	 * Should specify the expected response notification here. Problem is that
+	 * the response will be coming from a different GuC. By the end, it should
+	 * all add up as long as an equal number of messages are sent from each GuC
+	 * and to each GuC. However, in the middle negative reservation space errors
+	 * and such like can occur. Rather than add intrusive changes to the CT layer
+	 * it is simpler to just not bother counting it at all. The system should be
+	 * idle when running the selftest, and the selftest's notification total size
+	 * is well within the G2H allocation size. So there should be no issues with
+	 * needing to block for space, which is all the tracking code is really for.
+	 */
+	ret = xe_guc_ct_send(&guc->ct, action, total, 0, 0);
+	kunit_kfree(test, action);
+	KUNIT_ASSERT_EQ_MSG(test, 0, ret, "G2G send failed: %d [%d:%d -> %d:%d]\n", ret,
+			    gt_to_tile(gt)->id, G2G_DEV(gt), far_tile, far_dev);
+}
+
+/*
+ * NB: Can't use KUNIT_ASSERT and friends in here as this is called asynchronously
+ * from the G2H notification handler. Need that to actually complete rather than
+ * thread-abort in order to keep the rest of the driver alive!
+ */
+int xe_guc_g2g_test_notification(struct xe_guc *guc, u32 *msg, u32 len)
+{
+	struct xe_device *xe = guc_to_xe(guc);
+	struct xe_gt *rx_gt = guc_to_gt(guc), *test_gt, *tx_gt = NULL;
+	u32 tx_tile, tx_dev, rx_tile, rx_dev, idx, got_len;
+	struct g2g_test_payload *payload;
+	size_t payload_len;
+	int ret = 0, i;
+
+	payload_len = sizeof(*payload) / sizeof(u32);
+
+	if (unlikely(len != (G2H_LEN_DW_G2G_NOTIFY_MIN + payload_len))) {
+		xe_gt_err(rx_gt, "G2G test notification invalid length %u", len);
+		ret = -EPROTO;
+		goto done;
+	}
+
+	tx_tile = msg[0];
+	tx_dev = msg[1];
+	got_len = msg[2];
+	payload = (struct g2g_test_payload *)(msg + 3);
+
+	rx_tile = gt_to_tile(rx_gt)->id;
+	rx_dev = G2G_DEV(rx_gt);
+
+	if (got_len != payload_len) {
+		xe_gt_err(rx_gt, "G2G: Invalid payload length: %u vs %zu\n", got_len, payload_len);
+		ret = -EPROTO;
+		goto done;
+	}
+
+	if (payload->tx_dev != tx_dev || payload->tx_tile != tx_tile ||
+	    payload->rx_dev != rx_dev || payload->rx_tile != rx_tile) {
+		xe_gt_err(rx_gt, "G2G: Invalid payload: %d:%d -> %d:%d vs %d:%d -> %d:%d! [%d]\n",
+			  payload->tx_tile, payload->tx_dev, payload->rx_tile, payload->rx_dev,
+			  tx_tile, tx_dev, rx_tile, rx_dev, payload->seqno);
+		ret = -EPROTO;
+		goto done;
+	}
+
+	if (!xe->g2g_test_array) {
+		xe_gt_err(rx_gt, "G2G: Missing test array!\n");
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	for_each_gt(test_gt, xe, i) {
+		if (gt_to_tile(test_gt)->id != tx_tile)
+			continue;
+
+		if (G2G_DEV(test_gt) != tx_dev)
+			continue;
+
+		if (tx_gt) {
+			xe_gt_err(rx_gt, "G2G: Got duplicate TX GTs: %d vs %d for %d:%d!\n",
+				  tx_gt->info.id, test_gt->info.id, tx_tile, tx_dev);
+			ret = -EINVAL;
+			goto done;
+		}
+
+		tx_gt = test_gt;
+	}
+	if (!tx_gt) {
+		xe_gt_err(rx_gt, "G2G: Failed to find a TX GT for %d:%d!\n", tx_tile, tx_dev);
+		ret = -EINVAL;
+		goto done;
+	}
+
+	idx = (tx_gt->info.id * xe->info.gt_count) + rx_gt->info.id;
+
+	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",
+			  xe->g2g_test_array[idx], payload->seqno - 1,
+			  tx_tile, tx_dev, rx_tile, rx_dev);
+		ret = -EINVAL;
+		goto done;
+	}
+
+	xe->g2g_test_array[idx] = payload->seqno;
+
+done:
+	atomic_dec(&xe->g2g_test_count);
+	return ret;
+}
+
+/*
+ * 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;
+
+	for_each_gt(near_gt, xe, i) {
+		u32 near_tile = gt_to_tile(near_gt)->id;
+		u32 near_dev = G2G_DEV(near_gt);
+
+		for_each_gt(far_gt, xe, j) {
+			u32 far_tile = gt_to_tile(far_gt)->id;
+			u32 far_dev = G2G_DEV(far_gt);
+			struct g2g_test_payload payload;
+
+			if (far_gt->info.id == near_gt->info.id)
+				continue;
+
+			payload.tx_dev = near_dev;
+			payload.tx_tile = near_tile;
+			payload.rx_dev = far_dev;
+			payload.rx_tile = far_tile;
+			payload.seqno = seqno;
+			g2g_test_send(test, &near_gt->uc.guc, far_tile, far_dev, &payload);
+		}
+	}
+}
+
+#define WAIT_TIME_MS	100
+#define WAIT_COUNT	(1000 / WAIT_TIME_MS)
+
+static void g2g_wait_for_complete(void *_xe)
+{
+	struct xe_device *xe = (struct xe_device *)_xe;
+	struct kunit *test = kunit_get_current_test();
+	int wait = 0;
+
+	/* Wait for all G2H messages to be received */
+	while (atomic_read(&xe->g2g_test_count)) {
+		if (++wait > WAIT_COUNT)
+			break;
+
+		msleep(WAIT_TIME_MS);
+	}
+
+	KUNIT_ASSERT_EQ_MSG(test, 0, atomic_read(&xe->g2g_test_count),
+			    "Timed out waiting for notifications\n");
+	kunit_info(test, "Got all notifications back\n");
+}
+
+#undef WAIT_TIME_MS
+#undef WAIT_COUNT
+
+static void g2g_clean_array(void *_xe)
+{
+	struct xe_device *xe = (struct xe_device *)_xe;
+
+	xe->g2g_test_array = NULL;
+}
+
+#define NUM_LOOPS	16
+
+static void g2g_run_test(struct kunit *test, struct xe_device *xe)
+{
+	u32 seqno, max_array;
+	int ret, i, j;
+
+	max_array = xe->info.gt_count * xe->info.gt_count;
+	xe->g2g_test_array = kunit_kcalloc(test, max_array, sizeof(u32), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xe->g2g_test_array);
+
+	ret = kunit_add_action_or_reset(test, g2g_clean_array, xe);
+	KUNIT_ASSERT_EQ_MSG(test, 0, ret, "Failed to register clean up action\n");
+
+	/*
+	 * Send incrementing seqnos from all GuCs to all other GuCs in tile/GT order.
+	 * Tile/GT order doesn't really mean anything to the hardware but it is going
+	 * to be a fixed sequence every time.
+	 *
+	 * Verify that each one comes back having taken the correct route.
+	 */
+	ret = kunit_add_action(test, g2g_wait_for_complete, xe);
+	KUNIT_ASSERT_EQ_MSG(test, 0, ret, "Failed to register clean up action\n");
+	for (seqno = 1; seqno < NUM_LOOPS; seqno++)
+		g2g_test_in_order(test, xe, seqno);
+	seqno--;
+
+	kunit_release_action(test, &g2g_wait_for_complete, xe);
+
+	/* Check for the final seqno in each slot */
+	for (i = 0; i < xe->info.gt_count; i++) {
+		for (j = 0; j < xe->info.gt_count; j++) {
+			u32 idx = (j * xe->info.gt_count) + i;
+
+			if (i == j)
+				KUNIT_ASSERT_EQ_MSG(test, 0, xe->g2g_test_array[idx],
+						    "identity seqno modified: %d for %dx%d!\n",
+						    xe->g2g_test_array[idx], i, j);
+			else
+				KUNIT_ASSERT_EQ_MSG(test, seqno, xe->g2g_test_array[idx],
+						    "invalid seqno: %d vs %d for %dx%d!\n",
+						    xe->g2g_test_array[idx], seqno, i, j);
+		}
+	}
+
+	kunit_kfree(test, xe->g2g_test_array);
+	kunit_release_action(test, &g2g_clean_array, xe);
+
+	kunit_info(test, "Test passed\n");
+}
+
+#undef NUM_LOOPS
+
+static void g2g_ct_stop(struct xe_guc *guc)
+{
+	struct xe_gt *remote_gt, *gt = guc_to_gt(guc);
+	struct xe_device *xe = gt_to_xe(gt);
+	int i, t;
+
+	for_each_gt(remote_gt, xe, i) {
+		u32 tile, dev;
+
+		if (remote_gt->info.id == gt->info.id)
+			continue;
+
+		tile = gt_to_tile(remote_gt)->id;
+		dev = G2G_DEV(remote_gt);
+
+		for (t = 0; t < XE_G2G_TYPE_LIMIT; t++)
+			guc_g2g_deregister(guc, tile, dev, t);
+	}
+}
+
+/* Size of a single allocation that contains all G2G CTBs across all GTs */
+static u32 g2g_ctb_size(struct kunit *test, struct xe_device *xe)
+{
+	unsigned int count = xe->info.gt_count;
+	u32 num_channels = (count * (count - 1)) / 2;
+
+	kunit_info(test, "Size: (%d * %d / 2) * %d * 0x%08X + 0x%08X => 0x%08X [%d]\n",
+		   count, count - 1, XE_G2G_TYPE_LIMIT, G2G_BUFFER_SIZE, G2G_DESC_AREA_SIZE,
+		   num_channels * XE_G2G_TYPE_LIMIT * G2G_BUFFER_SIZE + G2G_DESC_AREA_SIZE,
+		   num_channels * XE_G2G_TYPE_LIMIT);
+
+	return num_channels * XE_G2G_TYPE_LIMIT * G2G_BUFFER_SIZE + G2G_DESC_AREA_SIZE;
+}
+
+/*
+ * Use the driver's regular CTB allocation scheme.
+ */
+static void g2g_alloc_default(struct kunit *test, struct xe_device *xe)
+{
+	struct xe_gt *gt;
+	int i;
+
+	kunit_info(test, "Default [tiles = %d, GTs = %d]\n",
+		   xe->info.tile_count, xe->info.gt_count);
+
+	for_each_gt(gt, xe, i) {
+		struct xe_guc *guc = &gt->uc.guc;
+		int ret;
+
+		ret = guc_g2g_alloc(guc);
+		KUNIT_ASSERT_EQ_MSG(test, 0, ret, "G2G alloc failed: %pe", ERR_PTR(ret));
+		continue;
+	}
+}
+
+static void g2g_distribute(struct kunit *test, struct xe_device *xe, struct xe_bo *bo)
+{
+	struct xe_gt *root_gt, *gt;
+	int i;
+
+	root_gt = xe_device_get_gt(xe, 0);
+	root_gt->uc.guc.g2g.bo = bo;
+	root_gt->uc.guc.g2g.owned = true;
+	kunit_info(test, "[%d.%d] Assigned 0x%p\n", gt_to_tile(root_gt)->id, root_gt->info.id, bo);
+
+	for_each_gt(gt, xe, i) {
+		if (gt->info.id != 0) {
+			gt->uc.guc.g2g.owned = false;
+			gt->uc.guc.g2g.bo = xe_bo_get(bo);
+			kunit_info(test, "[%d.%d] Pinned 0x%p\n",
+				   gt_to_tile(gt)->id, gt->info.id, gt->uc.guc.g2g.bo);
+		}
+
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, gt->uc.guc.g2g.bo);
+	}
+}
+
+/*
+ * Allocate a single blob on the host and split between all G2G CTBs.
+ */
+static void g2g_alloc_host(struct kunit *test, struct xe_device *xe)
+{
+	struct xe_bo *bo;
+	u32 g2g_size;
+
+	kunit_info(test, "Host [tiles = %d, GTs = %d]\n", xe->info.tile_count, xe->info.gt_count);
+
+	g2g_size = g2g_ctb_size(test, xe);
+	bo = xe_managed_bo_create_pin_map(xe, xe_device_get_root_tile(xe), g2g_size,
+					  XE_BO_FLAG_SYSTEM |
+					  XE_BO_FLAG_GGTT |
+					  XE_BO_FLAG_GGTT_ALL |
+					  XE_BO_FLAG_GGTT_INVALIDATE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bo);
+	kunit_info(test, "[HST] G2G buffer create: 0x%p\n", bo);
+
+	xe_map_memset(xe, &bo->vmap, 0, 0, g2g_size);
+
+	g2g_distribute(test, xe, bo);
+}
+
+/*
+ * Allocate a single blob on the given tile and split between all G2G CTBs.
+ */
+static void g2g_alloc_tile(struct kunit *test, struct xe_device *xe, struct xe_tile *tile)
+{
+	struct xe_bo *bo;
+	u32 g2g_size;
+
+	KUNIT_ASSERT_TRUE(test, IS_DGFX(xe));
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, tile);
+
+	kunit_info(test, "Tile %d [tiles = %d, GTs = %d]\n",
+		   tile->id, xe->info.tile_count, xe->info.gt_count);
+
+	g2g_size = g2g_ctb_size(test, xe);
+	bo = xe_managed_bo_create_pin_map(xe, tile, g2g_size,
+					  XE_BO_FLAG_VRAM_IF_DGFX(tile) |
+					  XE_BO_FLAG_GGTT |
+					  XE_BO_FLAG_GGTT_ALL |
+					  XE_BO_FLAG_GGTT_INVALIDATE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bo);
+	kunit_info(test, "[%d.*] G2G buffer create: 0x%p\n", tile->id, bo);
+
+	xe_map_memset(xe, &bo->vmap, 0, 0, g2g_size);
+
+	g2g_distribute(test, xe, bo);
+}
+
+static void g2g_free(struct kunit *test, struct xe_device *xe)
+{
+	struct xe_gt *gt;
+	struct xe_bo *bo;
+	int i;
+
+	for_each_gt(gt, xe, i) {
+		bo = gt->uc.guc.g2g.bo;
+		if (!bo)
+			continue;
+
+		if (gt->uc.guc.g2g.owned) {
+			xe_managed_bo_unpin_map_no_vm(xe, bo);
+			kunit_info(test, "[%d.%d] Unmapped 0x%p\n",
+				   gt_to_tile(gt)->id, gt->info.id, bo);
+		} else {
+			xe_bo_put(bo);
+			kunit_info(test, "[%d.%d] Unpinned 0x%p\n",
+				   gt_to_tile(gt)->id, gt->info.id, bo);
+		}
+
+		gt->uc.guc.g2g.bo = NULL;
+	}
+}
+
+static void g2g_stop(struct kunit *test, struct xe_device *xe)
+{
+	struct xe_gt *gt;
+	int i;
+
+	for_each_gt(gt, xe, i) {
+		struct xe_guc *guc = &gt->uc.guc;
+
+		if (!guc->g2g.bo)
+			continue;
+
+		g2g_ct_stop(guc);
+	}
+
+	g2g_free(test, xe);
+}
+
+/*
+ * Generate a unique id for each bi-directional CTB for each pair of
+ * near and far tiles/devices. The id can then be used as an index into
+ * a single allocation that is sub-divided into multiple CTBs.
+ *
+ * For example, with two devices per tile and two tiles, the table should
+ * look like:
+ *           Far <tile>.<dev>
+ *         0.0   0.1   1.0   1.1
+ * N 0.0  --/-- 00/01 02/03 04/05
+ * e 0.1  01/00 --/-- 06/07 08/09
+ * a 1.0  03/02 07/06 --/-- 10/11
+ * r 1.1  05/04 09/08 11/10 --/--
+ *
+ * Where each entry is Rx/Tx channel id.
+ *
+ * So GuC #3 (tile 1, dev 1) talking to GuC #2 (tile 1, dev 0) would
+ * be reading from channel #11 and writing to channel #10. Whereas,
+ * GuC #2 talking to GuC #3 would be read on #10 and write to #11.
+ */
+static int g2g_slot_flat(u32 near_tile, u32 near_dev, u32 far_tile, u32 far_dev,
+			 u32 type, u32 max_inst, bool have_dev)
+{
+	u32 near = near_tile, far = far_tile;
+	u32 idx = 0, x, y, direction;
+	int i;
+
+	if (have_dev) {
+		near = (near << 1) | near_dev;
+		far = (far << 1) | far_dev;
+	}
+
+	/* No need to send to one's self */
+	if (far == near)
+		return -1;
+
+	if (far > near) {
+		/* Top right table half */
+		x = far;
+		y = near;
+
+		/* T/R is 'forwards' direction */
+		direction = type;
+	} else {
+		/* Bottom left table half */
+		x = near;
+		y = far;
+
+		/* B/L is 'backwards' direction */
+		direction = (1 - type);
+	}
+
+	/* Count the rows prior to the target */
+	for (i = y; i > 0; i--)
+		idx += max_inst - i;
+
+	/* Count this row up to the target */
+	idx += (x - 1 - y);
+
+	/* Slots are in Rx/Tx pairs */
+	idx *= 2;
+
+	/* Pick Rx/Tx direction */
+	idx += direction;
+
+	return idx;
+}
+
+static int g2g_register_flat(struct xe_guc *guc, u32 far_tile, u32 far_dev, u32 type, bool have_dev)
+{
+	struct xe_gt *gt = guc_to_gt(guc);
+	struct xe_device *xe = gt_to_xe(gt);
+	u32 near_tile = gt_to_tile(gt)->id;
+	u32 near_dev = G2G_DEV(gt);
+	u32 max = xe->info.gt_count;
+	int idx;
+	u32 base, desc, buf;
+
+	if (!guc->g2g.bo)
+		return -ENODEV;
+
+	idx = g2g_slot_flat(near_tile, near_dev, far_tile, far_dev, type, max, have_dev);
+	xe_assert(xe, idx >= 0);
+
+	base = guc_bo_ggtt_addr(guc, guc->g2g.bo);
+	desc = base + idx * G2G_DESC_SIZE;
+	buf = base + idx * G2G_BUFFER_SIZE + G2G_DESC_AREA_SIZE;
+
+	xe_assert(xe, (desc - base + G2G_DESC_SIZE) <= G2G_DESC_AREA_SIZE);
+	xe_assert(xe, (buf - base + G2G_BUFFER_SIZE) <= xe_bo_size(guc->g2g.bo));
+
+	return guc_action_register_g2g_buffer(guc, type, far_tile, far_dev,
+					      desc, buf, G2G_BUFFER_SIZE);
+}
+
+static void g2g_start(struct kunit *test, struct xe_guc *guc)
+{
+	struct xe_gt *remote_gt, *gt = guc_to_gt(guc);
+	struct xe_device *xe = gt_to_xe(gt);
+	unsigned int i;
+	int t, ret;
+	bool have_dev;
+
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, guc->g2g.bo);
+
+	/* GuC interface will need extending if more GT device types are ever created. */
+	KUNIT_ASSERT_TRUE(test,
+			  (gt->info.type == XE_GT_TYPE_MAIN) ||
+			  (gt->info.type == XE_GT_TYPE_MEDIA));
+
+	/* Channel numbering depends on whether there are multiple GTs per tile */
+	have_dev = xe->info.gt_count > xe->info.tile_count;
+
+	for_each_gt(remote_gt, xe, i) {
+		u32 tile, dev;
+
+		if (remote_gt->info.id == gt->info.id)
+			continue;
+
+		tile = gt_to_tile(remote_gt)->id;
+		dev = G2G_DEV(remote_gt);
+
+		for (t = 0; t < XE_G2G_TYPE_LIMIT; t++) {
+			ret = g2g_register_flat(guc, tile, dev, t, have_dev);
+			KUNIT_ASSERT_EQ_MSG(test, 0, ret, "G2G register failed: %pe", ERR_PTR(ret));
+		}
+	}
+}
+
+enum {
+	G2G_CTB_TYPE_DEFAULT,
+	G2G_CTB_TYPE_HOST,
+	G2G_CTB_TYPE_TILE,
+};
+
+static void g2g_reinit(struct kunit *test, struct xe_device *xe, int ctb_type, struct xe_tile *tile)
+{
+	struct xe_gt *gt;
+	int i, found = 0;
+
+	g2g_stop(test, xe);
+
+	for_each_gt(gt, xe, i) {
+		struct xe_guc *guc = &gt->uc.guc;
+
+		KUNIT_ASSERT_NULL(test, guc->g2g.bo);
+	}
+
+	switch (ctb_type) {
+	case G2G_CTB_TYPE_DEFAULT:
+		g2g_alloc_default(test, xe);
+		break;
+
+	case G2G_CTB_TYPE_HOST:
+		g2g_alloc_host(test, xe);
+		break;
+
+	case G2G_CTB_TYPE_TILE:
+		g2g_alloc_tile(test, xe, tile);
+		break;
+
+	default:
+		KUNIT_ASSERT_TRUE(test, false);
+	}
+
+	for_each_gt(gt, xe, i) {
+		struct xe_guc *guc = &gt->uc.guc;
+
+		if (!guc->g2g.bo)
+			continue;
+
+		g2g_start(test, guc);
+		found++;
+	}
+
+	KUNIT_ASSERT_GT_MSG(test, found, 1, "insufficient G2G channels running: %d", found);
+
+	kunit_info(test, "Testing across %d GTs\n", found);
+}
+
+static void g2g_recreate_ctb(void *_xe)
+{
+	struct xe_device *xe = (struct xe_device *)_xe;
+	struct kunit *test = kunit_get_current_test();
+
+	g2g_stop(test, xe);
+
+	if (xe_guc_g2g_wanted(xe))
+		g2g_reinit(test, xe, G2G_CTB_TYPE_DEFAULT, NULL);
+}
+
+static void g2g_pm_runtime_put(void *_xe)
+{
+	struct xe_device *xe = (struct xe_device *)_xe;
+
+	xe_pm_runtime_put(xe);
+}
+
+static void g2g_pm_runtime_get(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	int ret;
+
+	xe_pm_runtime_get(xe);
+	ret = kunit_add_action_or_reset(test, g2g_pm_runtime_put, xe);
+	KUNIT_ASSERT_EQ_MSG(test, 0, ret, "Failed to register runtime PM action\n");
+}
+
+static void g2g_check_skip(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	struct xe_gt *gt;
+	int i;
+
+	if (IS_SRIOV_VF(xe))
+		kunit_skip(test, "not supported from a VF");
+
+	if (xe->info.gt_count <= 1)
+		kunit_skip(test, "not enough GTs");
+
+	for_each_gt(gt, xe, i) {
+		struct xe_guc *guc = &gt->uc.guc;
+
+		if (guc->fw.build_type == CSS_UKERNEL_INFO_BUILDTYPE_PROD)
+			kunit_skip(test,
+				   "G2G test interface not available in production firmware builds\n");
+	}
+}
+
+/*
+ * Simple test that does not try to recreate the CTBs.
+ * Requires that the platform already enables G2G comms
+ * but has no risk of leaving the system in a broken state
+ * afterwards.
+ */
+static void xe_live_guc_g2g_kunit_default(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+
+	if (!xe_guc_g2g_wanted(xe))
+		kunit_skip(test, "G2G not enabled");
+
+	g2g_check_skip(test);
+
+	g2g_pm_runtime_get(test);
+
+	kunit_info(test, "Testing default CTBs\n");
+	g2g_run_test(test, xe);
+
+	kunit_release_action(test, &g2g_pm_runtime_put, xe);
+}
+
+/*
+ * More complex test that re-creates the CTBs in various location to
+ * test access to each location from each GuC. Can be run even on
+ * systems that do not enable G2G by default. On the other hand,
+ * because it recreates the CTBs, if something goes wrong it could
+ * leave the system with broken G2G comms.
+ */
+static void xe_live_guc_g2g_kunit_allmem(struct kunit *test)
+{
+	struct xe_device *xe = test->priv;
+	int ret;
+
+	g2g_check_skip(test);
+
+	g2g_pm_runtime_get(test);
+
+	/* Make sure to leave the system as we found it */
+	ret = kunit_add_action_or_reset(test, g2g_recreate_ctb, xe);
+	KUNIT_ASSERT_EQ_MSG(test, 0, ret, "Failed to register CTB re-creation action\n");
+
+	kunit_info(test, "Testing CTB type 'default'...\n");
+	g2g_reinit(test, xe, G2G_CTB_TYPE_DEFAULT, NULL);
+	g2g_run_test(test, xe);
+
+	kunit_info(test, "Testing CTB type 'host'...\n");
+	g2g_reinit(test, xe, G2G_CTB_TYPE_HOST, NULL);
+	g2g_run_test(test, xe);
+
+	if (IS_DGFX(xe)) {
+		struct xe_tile *tile;
+		int id;
+
+		for_each_tile(tile, xe, id) {
+			kunit_info(test, "Testing CTB type 'tile: #%d'...\n", id);
+
+			g2g_reinit(test, xe, G2G_CTB_TYPE_TILE, tile);
+			g2g_run_test(test, xe);
+		}
+	} else {
+		kunit_info(test, "Skipping local memory on integrated platform\n");
+	}
+
+	kunit_release_action(test, g2g_recreate_ctb, xe);
+	kunit_release_action(test, g2g_pm_runtime_put, xe);
+}
+
+static struct kunit_case xe_guc_g2g_tests[] = {
+	KUNIT_CASE_PARAM(xe_live_guc_g2g_kunit_default, xe_pci_live_device_gen_param),
+	KUNIT_CASE_PARAM(xe_live_guc_g2g_kunit_allmem, xe_pci_live_device_gen_param),
+	{}
+};
+
+VISIBLE_IF_KUNIT
+struct kunit_suite xe_guc_g2g_test_suite = {
+	.name = "xe_guc_g2g",
+	.test_cases = xe_guc_g2g_tests,
+	.init = xe_kunit_helper_xe_device_live_test_init,
+};
+EXPORT_SYMBOL_IF_KUNIT(xe_guc_g2g_test_suite);
diff --git a/drivers/gpu/drm/xe/tests/xe_live_test_mod.c b/drivers/gpu/drm/xe/tests/xe_live_test_mod.c
index 81277c77016d..c55e46f1ae92 100644
--- a/drivers/gpu/drm/xe/tests/xe_live_test_mod.c
+++ b/drivers/gpu/drm/xe/tests/xe_live_test_mod.c
@@ -10,12 +10,14 @@ extern struct kunit_suite xe_bo_shrink_test_suite;
 extern struct kunit_suite xe_dma_buf_test_suite;
 extern struct kunit_suite xe_migrate_test_suite;
 extern struct kunit_suite xe_mocs_test_suite;
+extern struct kunit_suite xe_guc_g2g_test_suite;
 
 kunit_test_suite(xe_bo_test_suite);
 kunit_test_suite(xe_bo_shrink_test_suite);
 kunit_test_suite(xe_dma_buf_test_suite);
 kunit_test_suite(xe_migrate_test_suite);
 kunit_test_suite(xe_mocs_test_suite);
+kunit_test_suite(xe_guc_g2g_test_suite);
 
 MODULE_AUTHOR("Intel Corporation");
 MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 38c8329b4d2c..0416b0eba3bf 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -576,6 +576,13 @@ struct xe_device {
 	atomic64_t global_total_pages;
 #endif
 
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+	/** @g2g_test_array: for testing G2G communications */
+	u32 *g2g_test_array;
+	/** @g2g_test_count: for testing G2G communications */
+	atomic_t g2g_test_count;
+#endif
+
 	/* private: */
 
 #if IS_ENABLED(CONFIG_DRM_XE_DISPLAY)
diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index 1ca7f4f27e26..7c069236d1be 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -1673,3 +1673,7 @@ void xe_guc_declare_wedged(struct xe_guc *guc)
 	xe_guc_ct_stop(&guc->ct);
 	xe_guc_submit_wedge(guc);
 }
+
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+#include "tests/xe_guc_g2g_test.c"
+#endif
diff --git a/drivers/gpu/drm/xe/xe_guc.h b/drivers/gpu/drm/xe/xe_guc.h
index 22cf019a11bf..1cca05967e62 100644
--- a/drivers/gpu/drm/xe/xe_guc.h
+++ b/drivers/gpu/drm/xe/xe_guc.h
@@ -53,6 +53,10 @@ void xe_guc_stop(struct xe_guc *guc);
 int xe_guc_start(struct xe_guc *guc);
 void xe_guc_declare_wedged(struct xe_guc *guc);
 
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+int xe_guc_g2g_test_notification(struct xe_guc *guc, u32 *payload, u32 len);
+#endif
+
 static inline u16 xe_engine_class_to_guc_class(enum xe_engine_class class)
 {
 	switch (class) {
diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index 3f4e6a46ff16..f44967f84d30 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -1439,6 +1439,11 @@ static int process_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
 	case XE_GUC_ACTION_NOTIFY_EXCEPTION:
 		ret = guc_crash_process_msg(ct, action);
 		break;
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+	case XE_GUC_ACTION_TEST_G2G_RECV:
+		ret = xe_guc_g2g_test_notification(guc, payload, adj_len);
+		break;
+#endif
 	default:
 		xe_gt_err(gt, "unexpected G2H action 0x%04x\n", action);
 	}
diff --git a/drivers/gpu/drm/xe/xe_guc_fwif.h b/drivers/gpu/drm/xe/xe_guc_fwif.h
index ca9f999d38d1..bc94f8d0f037 100644
--- a/drivers/gpu/drm/xe/xe_guc_fwif.h
+++ b/drivers/gpu/drm/xe/xe_guc_fwif.h
@@ -15,6 +15,7 @@
 #define G2H_LEN_DW_SCHED_CONTEXT_MODE_SET	4
 #define G2H_LEN_DW_DEREGISTER_CONTEXT		3
 #define G2H_LEN_DW_TLB_INVALIDATE		3
+#define G2H_LEN_DW_G2G_NOTIFY_MIN		3
 
 #define GUC_ID_MAX			65535
 #define GUC_ID_UNKNOWN			0xffffffff
-- 
2.49.0



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