Quelle  xe_guc_relay.c   Sprache: C

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2023 Intel Corporation
 */

#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/fault-inject.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_gt_sriov_pf_service.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_NOWAIT);
 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);
}
ALLOW_ERROR_INJECTION(xe_guc_relay_init, ERRNO); /* See xe_pci_probe() */

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)
{
 struct xe_gt *gt = relay_to_gt(relay);
 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]);

 if (IS_SRIOV_PF(relay_to_xe(relay)))
  ret = xe_gt_sriov_pf_service_process_request(gt, origin, msg, len, response, size);
 else
  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)
{
 bool is_empty;

 spin_lock(&relay->lock);
 is_empty = list_empty(&relay->incoming_actions);
 spin_unlock(&relay->lock);

 return !is_empty;

}

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