Adding upstream version 6.9.7.upstream/6.9.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 941 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_guc_relay.c b/drivers/gpu/drm/xe/xe_guc_relay.c
new file mode 100644
index 0000000000..c0a2d8d5d3
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_guc_relay.c
@@ -0,0 +1,941 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+
+#include <drm/drm_managed.h>
+
+#include <kunit/static_stub.h>
+#include <kunit/test-bug.h>
+
+#include "abi/guc_actions_sriov_abi.h"
+#include "abi/guc_relay_actions_abi.h"
+#include "abi/guc_relay_communication_abi.h"
+
+#include "xe_assert.h"
+#include "xe_device.h"
+#include "xe_gt.h"
+#include "xe_gt_sriov_printk.h"
+#include "xe_guc.h"
+#include "xe_guc_ct.h"
+#include "xe_guc_hxg_helpers.h"
+#include "xe_guc_relay.h"
+#include "xe_guc_relay_types.h"
+#include "xe_sriov.h"
+
+/*
+ * How long should we wait for the response?
+ * XXX this value is subject for the profiling.
+ */
+#define RELAY_TIMEOUT_MSEC	(2500)
+
+static void relays_worker_fn(struct work_struct *w);
+
+static struct xe_guc *relay_to_guc(struct xe_guc_relay *relay)
+{
+	return container_of(relay, struct xe_guc, relay);
+}
+
+static struct xe_guc_ct *relay_to_ct(struct xe_guc_relay *relay)
+{
+	return &relay_to_guc(relay)->ct;
+}
+
+static struct xe_gt *relay_to_gt(struct xe_guc_relay *relay)
+{
+	return guc_to_gt(relay_to_guc(relay));
+}
+
+static struct xe_device *relay_to_xe(struct xe_guc_relay *relay)
+{
+	return gt_to_xe(relay_to_gt(relay));
+}
+
+#define relay_assert(relay, condition)	xe_gt_assert(relay_to_gt(relay), condition)
+#define relay_notice(relay, msg...)	xe_gt_sriov_notice(relay_to_gt(relay), "relay: " msg)
+#define relay_debug(relay, msg...)	xe_gt_sriov_dbg_verbose(relay_to_gt(relay), "relay: " msg)
+
+static int relay_get_totalvfs(struct xe_guc_relay *relay)
+{
+	struct xe_device *xe = relay_to_xe(relay);
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+
+	KUNIT_STATIC_STUB_REDIRECT(relay_get_totalvfs, relay);
+	return IS_SRIOV_VF(xe) ? 0 : pci_sriov_get_totalvfs(pdev);
+}
+
+static bool relay_is_ready(struct xe_guc_relay *relay)
+{
+	return mempool_initialized(&relay->pool);
+}
+
+static u32 relay_get_next_rid(struct xe_guc_relay *relay)
+{
+	u32 rid;
+
+	spin_lock(&relay->lock);
+	rid = ++relay->last_rid;
+	spin_unlock(&relay->lock);
+
+	return rid;
+}
+
+/**
+ * struct relay_transaction - internal data used to handle transactions
+ *
+ * Relation between struct relay_transaction members::
+ *
+ *                 <-------------------- GUC_CTB_MAX_DWORDS -------------->
+ *                                  <-------- GUC_RELAY_MSG_MAX_LEN --->
+ *                 <--- offset ---> <--- request_len ------->
+ *                +----------------+-------------------------+----------+--+
+ *                |                |                         |          |  |
+ *                +----------------+-------------------------+----------+--+
+ *                ^                ^
+ *               /                /
+ *    request_buf          request
+ *
+ *                 <-------------------- GUC_CTB_MAX_DWORDS -------------->
+ *                                  <-------- GUC_RELAY_MSG_MAX_LEN --->
+ *                 <--- offset ---> <--- response_len --->
+ *                +----------------+----------------------+-------------+--+
+ *                |                |                      |             |  |
+ *                +----------------+----------------------+-------------+--+
+ *                ^                ^
+ *               /                /
+ *   response_buf         response
+ */
+struct relay_transaction {
+	/**
+	 * @incoming: indicates whether this transaction represents an incoming
+	 *            request from the remote VF/PF or this transaction
+	 *            represents outgoing request to the remote VF/PF.
+	 */
+	bool incoming;
+
+	/**
+	 * @remote: PF/VF identifier of the origin (or target) of the relay
+	 *          request message.
+	 */
+	u32 remote;
+
+	/** @rid: identifier of the VF/PF relay message. */
+	u32 rid;
+
+	/**
+	 * @request: points to the inner VF/PF request message, copied to the
+	 *           #response_buf starting at #offset.
+	 */
+	u32 *request;
+
+	/** @request_len: length of the inner VF/PF request message. */
+	u32 request_len;
+
+	/**
+	 * @response: points to the placeholder buffer where inner VF/PF
+	 *            response will be located, for outgoing transaction
+	 *            this could be caller's buffer (if provided) otherwise
+	 *            it points to the #response_buf starting at #offset.
+	 */
+	u32 *response;
+
+	/**
+	 * @response_len: length of the inner VF/PF response message (only
+	 *                if #status is 0), initially set to the size of the
+	 *                placeholder buffer where response message will be
+	 *                copied.
+	 */
+	u32 response_len;
+
+	/**
+	 * @offset: offset to the start of the inner VF/PF relay message inside
+	 *          buffers; this offset is equal the length of the outer GuC
+	 *          relay header message.
+	 */
+	u32 offset;
+
+	/**
+	 * @request_buf: buffer with VF/PF request message including outer
+	 *               transport message.
+	 */
+	u32 request_buf[GUC_CTB_MAX_DWORDS];
+
+	/**
+	 * @response_buf: buffer with VF/PF response message including outer
+	 *                transport message.
+	 */
+	u32 response_buf[GUC_CTB_MAX_DWORDS];
+
+	/**
+	 * @reply: status of the reply, 0 means that data pointed by the
+	 *         #response is valid.
+	 */
+	int reply;
+
+	/** @done: completion of the outgoing transaction. */
+	struct completion done;
+
+	/** @link: transaction list link */
+	struct list_head link;
+};
+
+static u32 prepare_pf2guc(u32 *msg, u32 target, u32 rid)
+{
+	msg[0] = FIELD_PREP(GUC_HXG_MSG_0_ORIGIN, GUC_HXG_ORIGIN_HOST) |
+		 FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) |
+		 FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION, XE_GUC_ACTION_PF2GUC_RELAY_TO_VF);
+	msg[1] = FIELD_PREP(PF2GUC_RELAY_TO_VF_REQUEST_MSG_1_VFID, target);
+	msg[2] = FIELD_PREP(PF2GUC_RELAY_TO_VF_REQUEST_MSG_2_RELAY_ID, rid);
+
+	return PF2GUC_RELAY_TO_VF_REQUEST_MSG_MIN_LEN;
+}
+
+static u32 prepare_vf2guc(u32 *msg, u32 rid)
+{
+	msg[0] = FIELD_PREP(GUC_HXG_MSG_0_ORIGIN, GUC_HXG_ORIGIN_HOST) |
+		 FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) |
+		 FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION, XE_GUC_ACTION_VF2GUC_RELAY_TO_PF);
+	msg[1] = FIELD_PREP(VF2GUC_RELAY_TO_PF_REQUEST_MSG_1_RELAY_ID, rid);
+
+	return VF2GUC_RELAY_TO_PF_REQUEST_MSG_MIN_LEN;
+}
+
+static struct relay_transaction *
+__relay_get_transaction(struct xe_guc_relay *relay, bool incoming, u32 remote, u32 rid,
+			const u32 *action, u32 action_len, u32 *resp, u32 resp_size)
+{
+	struct relay_transaction *txn;
+
+	relay_assert(relay, action_len >= GUC_RELAY_MSG_MIN_LEN);
+	relay_assert(relay, action_len <= GUC_RELAY_MSG_MAX_LEN);
+	relay_assert(relay, !(!!resp ^ !!resp_size));
+	relay_assert(relay, resp_size <= GUC_RELAY_MSG_MAX_LEN);
+	relay_assert(relay, resp_size == 0 || resp_size >= GUC_RELAY_MSG_MIN_LEN);
+
+	if (unlikely(!relay_is_ready(relay)))
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * For incoming requests we can't use GFP_KERNEL as those are delivered
+	 * with CTB lock held which is marked as used in the reclaim path.
+	 * Btw, that's one of the reason why we use mempool here!
+	 */
+	txn = mempool_alloc(&relay->pool, incoming ? GFP_ATOMIC : GFP_KERNEL);
+	if (!txn)
+		return ERR_PTR(-ENOMEM);
+
+	txn->incoming = incoming;
+	txn->remote = remote;
+	txn->rid = rid;
+	txn->offset = remote ?
+		prepare_pf2guc(incoming ? txn->response_buf : txn->request_buf, remote, rid) :
+		prepare_vf2guc(incoming ? txn->response_buf : txn->request_buf, rid);
+
+	relay_assert(relay, txn->offset);
+	relay_assert(relay, txn->offset + GUC_RELAY_MSG_MAX_LEN <= ARRAY_SIZE(txn->request_buf));
+	relay_assert(relay, txn->offset + GUC_RELAY_MSG_MAX_LEN <= ARRAY_SIZE(txn->response_buf));
+
+	txn->request = txn->request_buf + txn->offset;
+	memcpy(&txn->request_buf[txn->offset], action, sizeof(u32) * action_len);
+	txn->request_len = action_len;
+
+	txn->response = resp ?: txn->response_buf + txn->offset;
+	txn->response_len = resp_size ?: GUC_RELAY_MSG_MAX_LEN;
+	txn->reply = -ENOMSG;
+	INIT_LIST_HEAD(&txn->link);
+	init_completion(&txn->done);
+
+	return txn;
+}
+
+static struct relay_transaction *
+relay_new_transaction(struct xe_guc_relay *relay, u32 target, const u32 *action, u32 len,
+		      u32 *resp, u32 resp_size)
+{
+	u32 rid = relay_get_next_rid(relay);
+
+	return __relay_get_transaction(relay, false, target, rid, action, len, resp, resp_size);
+}
+
+static struct relay_transaction *
+relay_new_incoming_transaction(struct xe_guc_relay *relay, u32 origin, u32 rid,
+			       const u32 *action, u32 len)
+{
+	return __relay_get_transaction(relay, true, origin, rid, action, len, NULL, 0);
+}
+
+static void relay_release_transaction(struct xe_guc_relay *relay, struct relay_transaction *txn)
+{
+	relay_assert(relay, list_empty(&txn->link));
+
+	txn->offset = 0;
+	txn->response = NULL;
+	txn->reply = -ESTALE;
+	mempool_free(txn, &relay->pool);
+}
+
+static int relay_send_transaction(struct xe_guc_relay *relay, struct relay_transaction *txn)
+{
+	u32 len = txn->incoming ? txn->response_len : txn->request_len;
+	u32 *buf = txn->incoming ? txn->response_buf : txn->request_buf;
+	u32 *msg = buf + txn->offset;
+	int ret;
+
+	relay_assert(relay, txn->offset);
+	relay_assert(relay, txn->offset + len <= GUC_CTB_MAX_DWORDS);
+	relay_assert(relay, len >= GUC_RELAY_MSG_MIN_LEN);
+	relay_assert(relay, len <= GUC_RELAY_MSG_MAX_LEN);
+
+	relay_debug(relay, "sending %s.%u to %u = %*ph\n",
+		    guc_hxg_type_to_string(FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0])),
+		    txn->rid, txn->remote, (int)sizeof(u32) * len, msg);
+
+	ret = xe_guc_ct_send_block(relay_to_ct(relay), buf, len + txn->offset);
+
+	if (unlikely(ret > 0)) {
+		relay_notice(relay, "Unexpected data=%d from GuC, wrong ABI?\n", ret);
+		ret = -EPROTO;
+	}
+	if (unlikely(ret < 0)) {
+		relay_notice(relay, "Failed to send %s.%x to GuC (%pe) %*ph ...\n",
+			     guc_hxg_type_to_string(FIELD_GET(GUC_HXG_MSG_0_TYPE, buf[0])),
+			     FIELD_GET(GUC_HXG_REQUEST_MSG_0_ACTION, buf[0]),
+			     ERR_PTR(ret), (int)sizeof(u32) * txn->offset, buf);
+		relay_notice(relay, "Failed to send %s.%u to %u (%pe) %*ph\n",
+			     guc_hxg_type_to_string(FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0])),
+			     txn->rid, txn->remote, ERR_PTR(ret), (int)sizeof(u32) * len, msg);
+	}
+
+	return ret;
+}
+
+static void __fini_relay(struct drm_device *drm, void *arg)
+{
+	struct xe_guc_relay *relay = arg;
+
+	mempool_exit(&relay->pool);
+}
+
+/**
+ * xe_guc_relay_init - Initialize a &xe_guc_relay
+ * @relay: the &xe_guc_relay to initialize
+ *
+ * Initialize remaining members of &xe_guc_relay that may depend
+ * on the SR-IOV mode.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_guc_relay_init(struct xe_guc_relay *relay)
+{
+	const int XE_RELAY_MEMPOOL_MIN_NUM = 1;
+	struct xe_device *xe = relay_to_xe(relay);
+	int err;
+
+	relay_assert(relay, !relay_is_ready(relay));
+
+	if (!IS_SRIOV(xe))
+		return 0;
+
+	spin_lock_init(&relay->lock);
+	INIT_WORK(&relay->worker, relays_worker_fn);
+	INIT_LIST_HEAD(&relay->pending_relays);
+	INIT_LIST_HEAD(&relay->incoming_actions);
+
+	err = mempool_init_kmalloc_pool(&relay->pool, XE_RELAY_MEMPOOL_MIN_NUM +
+					relay_get_totalvfs(relay),
+					sizeof(struct relay_transaction));
+	if (err)
+		return err;
+
+	relay_debug(relay, "using mempool with %d elements\n", relay->pool.min_nr);
+
+	return drmm_add_action_or_reset(&xe->drm, __fini_relay, relay);
+}
+
+static u32 to_relay_error(int err)
+{
+	/* XXX: assume that relay errors match errno codes */
+	return err < 0 ? -err : GUC_RELAY_ERROR_UNDISCLOSED;
+}
+
+static int from_relay_error(u32 error)
+{
+	/* XXX: assume that relay errors match errno codes */
+	return error ? -error : -ENODATA;
+}
+
+static u32 sanitize_relay_error(u32 error)
+{
+	/* XXX TBD if generic error codes will be allowed */
+	if (!IS_ENABLED(CONFIG_DRM_XE_DEBUG))
+		error = GUC_RELAY_ERROR_UNDISCLOSED;
+	return error;
+}
+
+static u32 sanitize_relay_error_hint(u32 hint)
+{
+	/* XXX TBD if generic error codes will be allowed */
+	if (!IS_ENABLED(CONFIG_DRM_XE_DEBUG))
+		hint = 0;
+	return hint;
+}
+
+static u32 prepare_error_reply(u32 *msg, u32 error, u32 hint)
+{
+	msg[0] = FIELD_PREP(GUC_HXG_MSG_0_ORIGIN, GUC_HXG_ORIGIN_HOST) |
+		 FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_RESPONSE_FAILURE) |
+		 FIELD_PREP(GUC_HXG_FAILURE_MSG_0_HINT, hint) |
+		 FIELD_PREP(GUC_HXG_FAILURE_MSG_0_ERROR, error);
+
+	XE_WARN_ON(!FIELD_FIT(GUC_HXG_FAILURE_MSG_0_ERROR, error));
+	XE_WARN_ON(!FIELD_FIT(GUC_HXG_FAILURE_MSG_0_HINT, hint));
+
+	return GUC_HXG_FAILURE_MSG_LEN;
+}
+
+static void relay_testonly_nop(struct xe_guc_relay *relay)
+{
+	KUNIT_STATIC_STUB_REDIRECT(relay_testonly_nop, relay);
+}
+
+static int relay_send_message_and_wait(struct xe_guc_relay *relay,
+				       struct relay_transaction *txn,
+				       u32 *buf, u32 buf_size)
+{
+	unsigned long timeout = msecs_to_jiffies(RELAY_TIMEOUT_MSEC);
+	u32 *msg = &txn->request_buf[txn->offset];
+	u32 len = txn->request_len;
+	u32 type, action, data0;
+	int ret;
+	long n;
+
+	type = FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]);
+	action = FIELD_GET(GUC_HXG_REQUEST_MSG_0_ACTION, msg[0]);
+	data0 = FIELD_GET(GUC_HXG_REQUEST_MSG_0_DATA0, msg[0]);
+
+	relay_debug(relay, "%s.%u to %u action %#x:%u\n",
+		    guc_hxg_type_to_string(type),
+		    txn->rid, txn->remote, action, data0);
+
+	/* list ordering does not need to match RID ordering */
+	spin_lock(&relay->lock);
+	list_add_tail(&txn->link, &relay->pending_relays);
+	spin_unlock(&relay->lock);
+
+resend:
+	ret = relay_send_transaction(relay, txn);
+	if (unlikely(ret < 0))
+		goto unlink;
+
+wait:
+	n = wait_for_completion_timeout(&txn->done, timeout);
+	if (unlikely(n == 0 && txn->reply)) {
+		ret = -ETIME;
+		goto unlink;
+	}
+
+	relay_debug(relay, "%u.%u reply %d after %u msec\n",
+		    txn->remote, txn->rid, txn->reply, jiffies_to_msecs(timeout - n));
+	if (unlikely(txn->reply)) {
+		reinit_completion(&txn->done);
+		if (txn->reply == -EAGAIN)
+			goto resend;
+		if (txn->reply == -EBUSY) {
+			relay_testonly_nop(relay);
+			goto wait;
+		}
+		if (txn->reply > 0)
+			ret = from_relay_error(txn->reply);
+		else
+			ret = txn->reply;
+		goto unlink;
+	}
+
+	relay_debug(relay, "%u.%u response %*ph\n", txn->remote, txn->rid,
+		    (int)sizeof(u32) * txn->response_len, txn->response);
+	relay_assert(relay, txn->response_len >= GUC_RELAY_MSG_MIN_LEN);
+	ret = txn->response_len;
+
+unlink:
+	spin_lock(&relay->lock);
+	list_del_init(&txn->link);
+	spin_unlock(&relay->lock);
+
+	if (unlikely(ret < 0)) {
+		relay_notice(relay, "Unsuccessful %s.%u %#x:%u to %u (%pe) %*ph\n",
+			     guc_hxg_type_to_string(type), txn->rid,
+			     action, data0, txn->remote, ERR_PTR(ret),
+			     (int)sizeof(u32) * len, msg);
+	}
+
+	return ret;
+}
+
+static int relay_send_to(struct xe_guc_relay *relay, u32 target,
+			 const u32 *msg, u32 len, u32 *buf, u32 buf_size)
+{
+	struct relay_transaction *txn;
+	int ret;
+
+	relay_assert(relay, len >= GUC_RELAY_MSG_MIN_LEN);
+	relay_assert(relay, len <= GUC_RELAY_MSG_MAX_LEN);
+	relay_assert(relay, FIELD_GET(GUC_HXG_MSG_0_ORIGIN, msg[0]) == GUC_HXG_ORIGIN_HOST);
+	relay_assert(relay, guc_hxg_type_is_action(FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0])));
+
+	if (unlikely(!relay_is_ready(relay)))
+		return -ENODEV;
+
+	txn = relay_new_transaction(relay, target, msg, len, buf, buf_size);
+	if (IS_ERR(txn))
+		return PTR_ERR(txn);
+
+	switch (FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0])) {
+	case GUC_HXG_TYPE_REQUEST:
+		ret = relay_send_message_and_wait(relay, txn, buf, buf_size);
+		break;
+	case GUC_HXG_TYPE_FAST_REQUEST:
+		relay_assert(relay, !GUC_HXG_TYPE_FAST_REQUEST);
+		fallthrough;
+	case GUC_HXG_TYPE_EVENT:
+		ret = relay_send_transaction(relay, txn);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	relay_release_transaction(relay, txn);
+	return ret;
+}
+
+#ifdef CONFIG_PCI_IOV
+/**
+ * xe_guc_relay_send_to_vf - Send a message to the VF.
+ * @relay: the &xe_guc_relay which will send the message
+ * @target: target VF number
+ * @msg: request message to be sent
+ * @len: length of the request message (in dwords, can't be 0)
+ * @buf: placeholder for the response message
+ * @buf_size: size of the response message placeholder (in dwords)
+ *
+ * This function can only be used by the driver running in the SR-IOV PF mode.
+ *
+ * Return: Non-negative response length (in dwords) or
+ *         a negative error code on failure.
+ */
+int xe_guc_relay_send_to_vf(struct xe_guc_relay *relay, u32 target,
+			    const u32 *msg, u32 len, u32 *buf, u32 buf_size)
+{
+	relay_assert(relay, IS_SRIOV_PF(relay_to_xe(relay)));
+
+	return relay_send_to(relay, target, msg, len, buf, buf_size);
+}
+#endif
+
+/**
+ * xe_guc_relay_send_to_pf - Send a message to the PF.
+ * @relay: the &xe_guc_relay which will send the message
+ * @msg: request message to be sent
+ * @len: length of the message (in dwords, can't be 0)
+ * @buf: placeholder for the response message
+ * @buf_size: size of the response message placeholder (in dwords)
+ *
+ * This function can only be used by driver running in SR-IOV VF mode.
+ *
+ * Return: Non-negative response length (in dwords) or
+ *         a negative error code on failure.
+ */
+int xe_guc_relay_send_to_pf(struct xe_guc_relay *relay,
+			    const u32 *msg, u32 len, u32 *buf, u32 buf_size)
+{
+	relay_assert(relay, IS_SRIOV_VF(relay_to_xe(relay)));
+
+	return relay_send_to(relay, PFID, msg, len, buf, buf_size);
+}
+
+static int relay_handle_reply(struct xe_guc_relay *relay, u32 origin,
+			      u32 rid, int reply, const u32 *msg, u32 len)
+{
+	struct relay_transaction *pending;
+	int err = -ESRCH;
+
+	spin_lock(&relay->lock);
+	list_for_each_entry(pending, &relay->pending_relays, link) {
+		if (pending->remote != origin || pending->rid != rid) {
+			relay_debug(relay, "%u.%u still awaits response\n",
+				    pending->remote, pending->rid);
+			continue;
+		}
+		err = 0; /* found! */
+		if (reply == 0) {
+			if (len > pending->response_len) {
+				reply = -ENOBUFS;
+				err = -ENOBUFS;
+			} else {
+				memcpy(pending->response, msg, 4 * len);
+				pending->response_len = len;
+			}
+		}
+		pending->reply = reply;
+		complete_all(&pending->done);
+		break;
+	}
+	spin_unlock(&relay->lock);
+
+	return err;
+}
+
+static int relay_handle_failure(struct xe_guc_relay *relay, u32 origin,
+				u32 rid, const u32 *msg, u32 len)
+{
+	int error = FIELD_GET(GUC_HXG_FAILURE_MSG_0_ERROR, msg[0]);
+	u32 hint __maybe_unused = FIELD_GET(GUC_HXG_FAILURE_MSG_0_HINT, msg[0]);
+
+	relay_assert(relay, len);
+	relay_debug(relay, "%u.%u error %#x (%pe) hint %u debug %*ph\n",
+		    origin, rid, error, ERR_PTR(-error), hint, 4 * (len - 1), msg + 1);
+
+	return relay_handle_reply(relay, origin, rid, error ?: -EREMOTEIO, NULL, 0);
+}
+
+static int relay_testloop_action_handler(struct xe_guc_relay *relay, u32 origin,
+					 const u32 *msg, u32 len, u32 *response, u32 size)
+{
+	static ktime_t last_reply = 0;
+	u32 type = FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]);
+	u32 action = FIELD_GET(GUC_HXG_REQUEST_MSG_0_ACTION, msg[0]);
+	u32 opcode = FIELD_GET(GUC_HXG_REQUEST_MSG_0_DATA0, msg[0]);
+	ktime_t now = ktime_get();
+	bool busy;
+	int ret;
+
+	relay_assert(relay, guc_hxg_type_is_action(type));
+	relay_assert(relay, action == GUC_RELAY_ACTION_VFXPF_TESTLOOP);
+
+	if (!IS_ENABLED(CONFIG_DRM_XE_DEBUG_SRIOV))
+		return -ECONNREFUSED;
+
+	if (!last_reply)
+		last_reply = now;
+	busy = ktime_before(now, ktime_add_ms(last_reply, 2 * RELAY_TIMEOUT_MSEC));
+	if (!busy)
+		last_reply = now;
+
+	switch (opcode) {
+	case VFXPF_TESTLOOP_OPCODE_NOP:
+		if (type == GUC_HXG_TYPE_EVENT)
+			return 0;
+		return guc_hxg_msg_encode_success(response, 0);
+	case VFXPF_TESTLOOP_OPCODE_BUSY:
+		if (type == GUC_HXG_TYPE_EVENT)
+			return -EPROTO;
+		msleep(RELAY_TIMEOUT_MSEC / 8);
+		if (busy)
+			return -EINPROGRESS;
+		return guc_hxg_msg_encode_success(response, 0);
+	case VFXPF_TESTLOOP_OPCODE_RETRY:
+		if (type == GUC_HXG_TYPE_EVENT)
+			return -EPROTO;
+		msleep(RELAY_TIMEOUT_MSEC / 8);
+		if (busy)
+			return guc_hxg_msg_encode_retry(response, 0);
+		return guc_hxg_msg_encode_success(response, 0);
+	case VFXPF_TESTLOOP_OPCODE_ECHO:
+		if (type == GUC_HXG_TYPE_EVENT)
+			return -EPROTO;
+		if (size < len)
+			return -ENOBUFS;
+		ret = guc_hxg_msg_encode_success(response, len);
+		memcpy(response + ret, msg + ret, (len - ret) * sizeof(u32));
+		return len;
+	case VFXPF_TESTLOOP_OPCODE_FAIL:
+		return -EHWPOISON;
+	default:
+		break;
+	}
+
+	relay_notice(relay, "Unexpected action %#x opcode %#x\n", action, opcode);
+	return -EBADRQC;
+}
+
+static int relay_action_handler(struct xe_guc_relay *relay, u32 origin,
+				const u32 *msg, u32 len, u32 *response, u32 size)
+{
+	u32 type;
+	int ret;
+
+	relay_assert(relay, len >= GUC_HXG_MSG_MIN_LEN);
+
+	if (FIELD_GET(GUC_HXG_REQUEST_MSG_0_ACTION, msg[0]) == GUC_RELAY_ACTION_VFXPF_TESTLOOP)
+		return relay_testloop_action_handler(relay, origin, msg, len, response, size);
+
+	type = FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]);
+
+	/* XXX: PF services will be added later */
+	ret = -EOPNOTSUPP;
+
+	if (type == GUC_HXG_TYPE_EVENT)
+		relay_assert(relay, ret <= 0);
+
+	return ret;
+}
+
+static struct relay_transaction *relay_dequeue_transaction(struct xe_guc_relay *relay)
+{
+	struct relay_transaction *txn;
+
+	spin_lock(&relay->lock);
+	txn = list_first_entry_or_null(&relay->incoming_actions, struct relay_transaction, link);
+	if (txn)
+		list_del_init(&txn->link);
+	spin_unlock(&relay->lock);
+
+	return txn;
+}
+
+static void relay_process_incoming_action(struct xe_guc_relay *relay)
+{
+	struct relay_transaction *txn;
+	bool again = false;
+	u32 type;
+	int ret;
+
+	txn = relay_dequeue_transaction(relay);
+	if (!txn)
+		return;
+
+	type = FIELD_GET(GUC_HXG_MSG_0_TYPE, txn->request_buf[txn->offset]);
+
+	ret = relay_action_handler(relay, txn->remote,
+				   txn->request_buf + txn->offset, txn->request_len,
+				   txn->response_buf + txn->offset,
+				   ARRAY_SIZE(txn->response_buf) - txn->offset);
+
+	if (ret == -EINPROGRESS) {
+		again = true;
+		ret = guc_hxg_msg_encode_busy(txn->response_buf + txn->offset, 0);
+	}
+
+	if (ret > 0) {
+		txn->response_len = ret;
+		ret = relay_send_transaction(relay, txn);
+	}
+
+	if (ret < 0) {
+		u32 error = to_relay_error(ret);
+
+		relay_notice(relay, "Failed to handle %s.%u from %u (%pe) %*ph\n",
+			     guc_hxg_type_to_string(type), txn->rid, txn->remote,
+			     ERR_PTR(ret), 4 * txn->request_len, txn->request_buf + txn->offset);
+
+		txn->response_len = prepare_error_reply(txn->response_buf + txn->offset,
+							txn->remote ?
+							sanitize_relay_error(error) : error,
+							txn->remote ?
+							sanitize_relay_error_hint(-ret) : -ret);
+		ret = relay_send_transaction(relay, txn);
+		again = false;
+	}
+
+	if (again) {
+		spin_lock(&relay->lock);
+		list_add(&txn->link, &relay->incoming_actions);
+		spin_unlock(&relay->lock);
+		return;
+	}
+
+	if (unlikely(ret < 0))
+		relay_notice(relay, "Failed to process action.%u (%pe) %*ph\n",
+			     txn->rid, ERR_PTR(ret), 4 * txn->request_len,
+			     txn->request_buf + txn->offset);
+
+	relay_release_transaction(relay, txn);
+}
+
+static bool relay_needs_worker(struct xe_guc_relay *relay)
+{
+	return !list_empty(&relay->incoming_actions);
+}
+
+static void relay_kick_worker(struct xe_guc_relay *relay)
+{
+	KUNIT_STATIC_STUB_REDIRECT(relay_kick_worker, relay);
+	queue_work(relay_to_xe(relay)->sriov.wq, &relay->worker);
+}
+
+static void relays_worker_fn(struct work_struct *w)
+{
+	struct xe_guc_relay *relay = container_of(w, struct xe_guc_relay, worker);
+
+	relay_process_incoming_action(relay);
+
+	if (relay_needs_worker(relay))
+		relay_kick_worker(relay);
+}
+
+static int relay_queue_action_msg(struct xe_guc_relay *relay, u32 origin, u32 rid,
+				  const u32 *msg, u32 len)
+{
+	struct relay_transaction *txn;
+
+	txn = relay_new_incoming_transaction(relay, origin, rid, msg, len);
+	if (IS_ERR(txn))
+		return PTR_ERR(txn);
+
+	spin_lock(&relay->lock);
+	list_add_tail(&txn->link, &relay->incoming_actions);
+	spin_unlock(&relay->lock);
+
+	relay_kick_worker(relay);
+	return 0;
+}
+
+static int relay_process_msg(struct xe_guc_relay *relay, u32 origin, u32 rid,
+			     const u32 *msg, u32 len)
+{
+	u32 type;
+	int err;
+
+	if (unlikely(len < GUC_HXG_MSG_MIN_LEN))
+		return -EPROTO;
+
+	if (FIELD_GET(GUC_HXG_MSG_0_ORIGIN, msg[0]) != GUC_HXG_ORIGIN_HOST)
+		return -EPROTO;
+
+	type = FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]);
+	relay_debug(relay, "received %s.%u from %u = %*ph\n",
+		    guc_hxg_type_to_string(type), rid, origin, 4 * len, msg);
+
+	switch (type) {
+	case GUC_HXG_TYPE_REQUEST:
+	case GUC_HXG_TYPE_FAST_REQUEST:
+	case GUC_HXG_TYPE_EVENT:
+		err = relay_queue_action_msg(relay, origin, rid, msg, len);
+		break;
+	case GUC_HXG_TYPE_RESPONSE_SUCCESS:
+		err = relay_handle_reply(relay, origin, rid, 0, msg, len);
+		break;
+	case GUC_HXG_TYPE_NO_RESPONSE_BUSY:
+		err = relay_handle_reply(relay, origin, rid, -EBUSY, NULL, 0);
+		break;
+	case GUC_HXG_TYPE_NO_RESPONSE_RETRY:
+		err = relay_handle_reply(relay, origin, rid, -EAGAIN, NULL, 0);
+		break;
+	case GUC_HXG_TYPE_RESPONSE_FAILURE:
+		err = relay_handle_failure(relay, origin, rid, msg, len);
+		break;
+	default:
+		err = -EBADRQC;
+	}
+
+	if (unlikely(err))
+		relay_notice(relay, "Failed to process %s.%u from %u (%pe) %*ph\n",
+			     guc_hxg_type_to_string(type), rid, origin,
+			     ERR_PTR(err), 4 * len, msg);
+
+	return err;
+}
+
+/**
+ * xe_guc_relay_process_guc2vf - Handle relay notification message from the GuC.
+ * @relay: the &xe_guc_relay which will handle the message
+ * @msg: message to be handled
+ * @len: length of the message (in dwords)
+ *
+ * This function will handle relay messages received from the GuC.
+ *
+ * This function is can only be used if driver is running in SR-IOV mode.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_guc_relay_process_guc2vf(struct xe_guc_relay *relay, const u32 *msg, u32 len)
+{
+	u32 rid;
+
+	relay_assert(relay, len >= GUC_HXG_MSG_MIN_LEN);
+	relay_assert(relay, FIELD_GET(GUC_HXG_MSG_0_ORIGIN, msg[0]) == GUC_HXG_ORIGIN_GUC);
+	relay_assert(relay, FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]) == GUC_HXG_TYPE_EVENT);
+	relay_assert(relay, FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, msg[0]) ==
+		     XE_GUC_ACTION_GUC2VF_RELAY_FROM_PF);
+
+	if (unlikely(!IS_SRIOV_VF(relay_to_xe(relay)) && !kunit_get_current_test()))
+		return -EPERM;
+
+	if (unlikely(!relay_is_ready(relay)))
+		return -ENODEV;
+
+	if (unlikely(len < GUC2VF_RELAY_FROM_PF_EVENT_MSG_MIN_LEN))
+		return -EPROTO;
+
+	if (unlikely(len > GUC2VF_RELAY_FROM_PF_EVENT_MSG_MAX_LEN))
+		return -EMSGSIZE;
+
+	if (unlikely(FIELD_GET(GUC_HXG_EVENT_MSG_0_DATA0, msg[0])))
+		return -EPFNOSUPPORT;
+
+	rid = FIELD_GET(GUC2VF_RELAY_FROM_PF_EVENT_MSG_1_RELAY_ID, msg[1]);
+
+	return relay_process_msg(relay, PFID, rid,
+				 msg + GUC2VF_RELAY_FROM_PF_EVENT_MSG_MIN_LEN,
+				 len - GUC2VF_RELAY_FROM_PF_EVENT_MSG_MIN_LEN);
+}
+
+#ifdef CONFIG_PCI_IOV
+/**
+ * xe_guc_relay_process_guc2pf - Handle relay notification message from the GuC.
+ * @relay: the &xe_guc_relay which will handle the message
+ * @msg: message to be handled
+ * @len: length of the message (in dwords)
+ *
+ * This function will handle relay messages received from the GuC.
+ *
+ * This function can only be used if driver is running in SR-IOV PF mode.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_guc_relay_process_guc2pf(struct xe_guc_relay *relay, const u32 *msg, u32 len)
+{
+	u32 origin, rid;
+	int err;
+
+	relay_assert(relay, len >= GUC_HXG_EVENT_MSG_MIN_LEN);
+	relay_assert(relay, FIELD_GET(GUC_HXG_MSG_0_ORIGIN, msg[0]) == GUC_HXG_ORIGIN_GUC);
+	relay_assert(relay, FIELD_GET(GUC_HXG_MSG_0_TYPE, msg[0]) == GUC_HXG_TYPE_EVENT);
+	relay_assert(relay, FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, msg[0]) ==
+		     XE_GUC_ACTION_GUC2PF_RELAY_FROM_VF);
+
+	if (unlikely(!IS_SRIOV_PF(relay_to_xe(relay)) && !kunit_get_current_test()))
+		return -EPERM;
+
+	if (unlikely(!relay_is_ready(relay)))
+		return -ENODEV;
+
+	if (unlikely(len < GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN))
+		return -EPROTO;
+
+	if (unlikely(len > GUC2PF_RELAY_FROM_VF_EVENT_MSG_MAX_LEN))
+		return -EMSGSIZE;
+
+	if (unlikely(FIELD_GET(GUC_HXG_EVENT_MSG_0_DATA0, msg[0])))
+		return -EPFNOSUPPORT;
+
+	origin = FIELD_GET(GUC2PF_RELAY_FROM_VF_EVENT_MSG_1_VFID, msg[1]);
+	rid = FIELD_GET(GUC2PF_RELAY_FROM_VF_EVENT_MSG_2_RELAY_ID, msg[2]);
+
+	if (unlikely(origin > relay_get_totalvfs(relay)))
+		return -ENOENT;
+
+	err = relay_process_msg(relay, origin, rid,
+				msg + GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN,
+				len - GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN);
+
+	return err;
+}
+#endif
+
+#if IS_BUILTIN(CONFIG_DRM_XE_KUNIT_TEST)
+#include "tests/xe_guc_relay_test.c"
+#endif