[PATCH 24.11] net/netvsc: support multi-process VF device removal

[Long Li]

[ upstream commit f741298f702772570ff20df000050483488092d0 ]

When a VF device is hot-removed by the primary process, secondary
processes must be notified to release their references to the VF port.
Without this, secondary processes retain stale port references leading
to crashes or undefined behavior when accessing the removed device.

This patch adds multi-process communication infrastructure to coordinate
VF removal across all processes:

- Shared memory (netvsc_shared_data) to track secondary process count
- Multi-process message handlers (NETVSC_MP_REQ_VF_REMOVE) to notify
  secondaries when primary removes a VF device
- Secondary handler calls rte_eth_dev_release_port() to cleanly release
  the VF port in its own process space
- Primary waits for all secondaries to acknowledge removal before
  proceeding

The implementation uses rte_mp_request_sync() to ensure all secondary
processes respond within NETVSC_MP_REQ_TIMEOUT_SEC (5 seconds) before
the primary completes the VF removal sequence.

Fixes: 7fc4c0997b04 ("net/netvsc: fix hot adding multiple VF PCI devices")
Cc: stable at dpdk.org

Signed-off-by: Long Li <longli at microsoft.com>
---
 drivers/net/netvsc/hn_ethdev.c | 307 +++++++++++++++++++++++++++++++--
 drivers/net/netvsc/hn_nvs.h    |   6 +
 drivers/net/netvsc/hn_vf.c     |   4 +
 3 files changed, 306 insertions(+), 11 deletions(-)

diff --git a/drivers/net/netvsc/hn_ethdev.c b/drivers/net/netvsc/hn_ethdev.c
index bfce541f2a..da6368457c 100644
--- a/drivers/net/netvsc/hn_ethdev.c
+++ b/drivers/net/netvsc/hn_ethdev.c
@@ -41,6 +41,31 @@
 #include "hn_nvs.h"
 #include "ndis.h"
 
+/* Spinlock for netvsc_shared_data */
+static rte_spinlock_t netvsc_shared_data_lock = RTE_SPINLOCK_INITIALIZER;
+
+static struct netvsc_shared_data {
+	RTE_ATOMIC(uint32_t) secondary_cnt;
+} *netvsc_shared_data;
+
+static const struct rte_memzone *netvsc_shared_mz;
+#define MZ_NETVSC_SHARED_DATA "netvsc_shared_data"
+
+static struct netvsc_local_data {
+	bool init_done;
+	unsigned int primary_cnt;
+	unsigned int secondary_cnt;
+} netvsc_local_data;
+
+#define NETVSC_MP_NAME "net_netvsc_mp"
+#define NETVSC_MP_REQ_TIMEOUT_SEC 5
+
+struct netvsc_mp_param {
+	enum netvsc_mp_req_type type;
+	int vf_port;
+	int result;
+};
+
 #define HN_TX_OFFLOAD_CAPS (RTE_ETH_TX_OFFLOAD_IPV4_CKSUM | \
 			    RTE_ETH_TX_OFFLOAD_TCP_CKSUM  | \
 			    RTE_ETH_TX_OFFLOAD_UDP_CKSUM  | \
@@ -1464,6 +1489,217 @@ eth_hn_dev_uninit(struct rte_eth_dev *eth_dev)
 	return ret_stop;
 }
 
+static int
+netvsc_mp_primary_handle(const struct rte_mp_msg *mp_msg __rte_unused,
+			  const void *peer __rte_unused)
+{
+	/* Stub function required for multi-process message handling registration */
+	return 0;
+}
+
+static void
+mp_init_msg(struct rte_mp_msg *msg, enum netvsc_mp_req_type type, int vf_port)
+{
+	struct netvsc_mp_param *param;
+
+	strlcpy(msg->name, NETVSC_MP_NAME, sizeof(msg->name));
+	msg->len_param = sizeof(*param);
+
+	param = (struct netvsc_mp_param *)msg->param;
+	param->type = type;
+	param->vf_port = vf_port;
+}
+
+static int netvsc_secondary_handle_device_remove(int vf_port)
+{
+	if (!rte_eth_dev_is_valid_port(vf_port)) {
+		/* VF not probed in this secondary — nothing to release */
+		PMD_DRV_LOG(DEBUG, "VF port %u not present in secondary, skipping",
+			    vf_port);
+		return 0;
+	}
+
+	PMD_DRV_LOG(DEBUG, "Secondary releasing VF port %d", vf_port);
+	return rte_eth_dev_release_port(&rte_eth_devices[vf_port]);
+}
+
+static int
+netvsc_mp_secondary_handle(const struct rte_mp_msg *mp_msg, const void *peer)
+{
+	struct rte_mp_msg mp_res = { 0 };
+	struct netvsc_mp_param *res = (struct netvsc_mp_param *)mp_res.param;
+	const struct netvsc_mp_param *param =
+		(const struct netvsc_mp_param *)mp_msg->param;
+	int ret = 0;
+
+	mp_init_msg(&mp_res, param->type, param->vf_port);
+
+	switch (param->type) {
+	case NETVSC_MP_REQ_VF_REMOVE:
+		res->result = netvsc_secondary_handle_device_remove(param->vf_port);
+		ret = rte_mp_reply(&mp_res, peer);
+		break;
+
+	default:
+		PMD_DRV_LOG(ERR, "Unknown primary MP type %u", param->type);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int netvsc_mp_init_primary(void)
+{
+	int ret;
+	ret = rte_mp_action_register(NETVSC_MP_NAME, netvsc_mp_primary_handle);
+	if (ret && rte_errno != ENOTSUP) {
+		PMD_DRV_LOG(ERR, "Failed to register primary handler %d %d",
+			ret, rte_errno);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void netvsc_mp_uninit_primary(void)
+{
+	rte_mp_action_unregister(NETVSC_MP_NAME);
+}
+
+static int netvsc_mp_init_secondary(void)
+{
+	return rte_mp_action_register(NETVSC_MP_NAME, netvsc_mp_secondary_handle);
+}
+
+static void netvsc_mp_uninit_secondary(void)
+{
+	rte_mp_action_unregister(NETVSC_MP_NAME);
+}
+
+int netvsc_mp_req_vf(struct hn_data *hv, enum netvsc_mp_req_type type,
+		     int vf_port)
+{
+	struct rte_mp_msg mp_req = { 0 };
+	struct rte_mp_msg *mp_res;
+	struct rte_mp_reply mp_rep = { 0 };
+	struct netvsc_mp_param *res;
+	struct timespec ts = {.tv_sec = NETVSC_MP_REQ_TIMEOUT_SEC, .tv_nsec = 0};
+	int i, ret;
+
+	/* if secondary count is 0, return */
+	if (rte_atomic_load_explicit(&netvsc_shared_data->secondary_cnt,
+			rte_memory_order_acquire) == 0)
+		return 0;
+
+	mp_init_msg(&mp_req, type, vf_port);
+
+	ret = rte_mp_request_sync(&mp_req, &mp_rep, &ts);
+	if (ret) {
+		if (rte_errno != ENOTSUP)
+			PMD_DRV_LOG(ERR, "port %u failed to request VF remove",
+				    hv->port_id);
+		else
+			ret = 0;
+		goto exit;
+	}
+
+	if (mp_rep.nb_sent != mp_rep.nb_received) {
+		PMD_DRV_LOG(ERR, "port %u not all secondaries responded type %d",
+			    hv->port_id, type);
+		ret = -1;
+		goto exit;
+	}
+	for (i = 0; i < mp_rep.nb_received; i++) {
+		mp_res = &mp_rep.msgs[i];
+		res = (struct netvsc_mp_param *)mp_res->param;
+		if (res->result) {
+			PMD_DRV_LOG(ERR, "port %u request failed on secondary %d",
+				    hv->port_id, i);
+			ret = -1;
+			goto exit;
+		}
+	}
+
+exit:
+	free(mp_rep.msgs);
+	return ret;
+}
+
+static int netvsc_init_once(void)
+{
+	int ret = 0;
+	const struct rte_memzone *secondary_mz;
+
+	if (netvsc_local_data.init_done)
+		return 0;
+
+	switch (rte_eal_process_type()) {
+	case RTE_PROC_PRIMARY:
+		netvsc_shared_mz = rte_memzone_reserve(MZ_NETVSC_SHARED_DATA,
+				sizeof(*netvsc_shared_data), SOCKET_ID_ANY, 0);
+		if (!netvsc_shared_mz) {
+			PMD_DRV_LOG(ERR, "Cannot allocate netvsc shared data");
+			return -rte_errno;
+		}
+		netvsc_shared_data = netvsc_shared_mz->addr;
+		rte_atomic_store_explicit(&netvsc_shared_data->secondary_cnt,
+				0, rte_memory_order_release);
+
+		ret = netvsc_mp_init_primary();
+		if (ret) {
+			rte_memzone_free(netvsc_shared_mz);
+			netvsc_shared_mz = NULL;
+			netvsc_shared_data = NULL;
+			break;
+		}
+
+		PMD_DRV_LOG(DEBUG, "MP INIT PRIMARY");
+		netvsc_local_data.init_done = true;
+		break;
+
+	case RTE_PROC_SECONDARY:
+		secondary_mz = rte_memzone_lookup(MZ_NETVSC_SHARED_DATA);
+		if (!secondary_mz) {
+			PMD_DRV_LOG(ERR, "Cannot attach netvsc shared data");
+			return -rte_errno;
+		}
+		netvsc_shared_data = secondary_mz->addr;
+		ret = netvsc_mp_init_secondary();
+		if (ret) {
+			netvsc_shared_data = NULL;
+			break;
+		}
+
+		PMD_DRV_LOG(DEBUG, "MP INIT SECONDARY");
+		netvsc_local_data.init_done = true;
+		break;
+
+	default:
+		/* Impossible */
+		ret = -EPROTO;
+		break;
+	}
+
+	return ret;
+}
+
+static void netvsc_uninit_once(void)
+{
+	if (netvsc_local_data.primary_cnt ||
+	    netvsc_local_data.secondary_cnt)
+		return;
+
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+		netvsc_mp_uninit_primary();
+		rte_memzone_free(netvsc_shared_mz);
+		netvsc_shared_mz = NULL;
+		netvsc_shared_data = NULL;
+	} else {
+		netvsc_mp_uninit_secondary();
+	}
+	netvsc_local_data.init_done = false;
+}
+
 static int eth_hn_probe(struct rte_vmbus_driver *drv __rte_unused,
 			struct rte_vmbus_device *dev)
 {
@@ -1472,23 +1708,57 @@ static int eth_hn_probe(struct rte_vmbus_driver *drv __rte_unused,
 
 	PMD_INIT_FUNC_TRACE();
 
+	rte_spinlock_lock(&netvsc_shared_data_lock);
+	ret = netvsc_init_once();
+	if (!ret) {
+		if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+			netvsc_local_data.primary_cnt++;
+		} else {
+			rte_atomic_fetch_add_explicit(&netvsc_shared_data->secondary_cnt,
+						      1, rte_memory_order_release);
+			netvsc_local_data.secondary_cnt++;
+		}
+	}
+	rte_spinlock_unlock(&netvsc_shared_data_lock);
+	if (ret)
+		return ret;
+
 	ret = rte_dev_event_monitor_start();
 	if (ret) {
 		PMD_DRV_LOG(ERR, "Failed to start device event monitoring");
-		return ret;
+		goto init_once_failed;
 	}
 
 	eth_dev = eth_dev_vmbus_allocate(dev, sizeof(struct hn_data));
-	if (!eth_dev)
-		return -ENOMEM;
+	if (!eth_dev) {
+		ret = -ENOMEM;
+		goto vmbus_alloc_failed;
+	}
 
 	ret = eth_hn_dev_init(eth_dev);
-	if (ret) {
-		eth_dev_vmbus_release(eth_dev);
-		rte_dev_event_monitor_stop();
+	if (ret)
+		goto dev_init_failed;
+
+	rte_eth_dev_probing_finish(eth_dev);
+	return ret;
+
+dev_init_failed:
+	eth_dev_vmbus_release(eth_dev);
+
+vmbus_alloc_failed:
+	rte_dev_event_monitor_stop();
+
+init_once_failed:
+	rte_spinlock_lock(&netvsc_shared_data_lock);
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+		netvsc_local_data.primary_cnt--;
 	} else {
-		rte_eth_dev_probing_finish(eth_dev);
+		rte_atomic_fetch_sub_explicit(&netvsc_shared_data->secondary_cnt,
+					      1, rte_memory_order_release);
+		netvsc_local_data.secondary_cnt--;
 	}
+	netvsc_uninit_once();
+	rte_spinlock_unlock(&netvsc_shared_data_lock);
 
 	return ret;
 }
@@ -1501,16 +1771,31 @@ static int eth_hn_remove(struct rte_vmbus_device *dev)
 	PMD_INIT_FUNC_TRACE();
 
 	eth_dev = rte_eth_dev_allocated(dev->device.name);
-	if (!eth_dev)
-		return 0; /* port already released */
+	if (!eth_dev) {
+		ret = 0; /* port already released */
+		goto uninit;
+	}
 
 	ret = eth_hn_dev_uninit(eth_dev);
 	if (ret)
-		return ret;
+		goto uninit;
 
 	eth_dev_vmbus_release(eth_dev);
 	rte_dev_event_monitor_stop();
-	return 0;
+
+uninit:
+	rte_spinlock_lock(&netvsc_shared_data_lock);
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+		netvsc_local_data.primary_cnt--;
+	} else {
+		rte_atomic_fetch_sub_explicit(&netvsc_shared_data->secondary_cnt,
+				1, rte_memory_order_release);
+		netvsc_local_data.secondary_cnt--;
+	}
+	netvsc_uninit_once();
+	rte_spinlock_unlock(&netvsc_shared_data_lock);
+
+	return ret;
 }
 
 /* Network device GUID */
diff --git a/drivers/net/netvsc/hn_nvs.h b/drivers/net/netvsc/hn_nvs.h
index 3766d2ee34..ce96eaf202 100644
--- a/drivers/net/netvsc/hn_nvs.h
+++ b/drivers/net/netvsc/hn_nvs.h
@@ -236,3 +236,9 @@ hn_nvs_send_sglist(struct vmbus_channel *chan,
 	return rte_vmbus_chan_send_sglist(chan, sg, sglen, nvs_msg, nvs_msglen,
 					  (uint64_t)sndc, need_sig);
 }
+
+enum netvsc_mp_req_type {
+	NETVSC_MP_REQ_VF_REMOVE = 1,
+};
+int netvsc_mp_req_vf(struct hn_data *hv, enum netvsc_mp_req_type type,
+		     int vf_port);
diff --git a/drivers/net/netvsc/hn_vf.c b/drivers/net/netvsc/hn_vf.c
index 2cd125f760..e9e52fbcfc 100644
--- a/drivers/net/netvsc/hn_vf.c
+++ b/drivers/net/netvsc/hn_vf.c
@@ -159,6 +159,10 @@ static void hn_remove_delayed(void *args)
 		PMD_DRV_LOG(ERR, "rte_eth_dev_close failed port_id=%u ret=%d",
 			    port_id, ret);
 
+	ret = netvsc_mp_req_vf(hv, NETVSC_MP_REQ_VF_REMOVE, port_id);
+	if (ret)
+		PMD_DRV_LOG(ERR, "failed to request secondary VF remove");
+
 	/* Remove the rte device when all its eth devices are removed */
 	all_eth_removed = true;
 	RTE_ETH_FOREACH_DEV_OF(port_id, dev) {
-- 
2.43.0