+static struct rte_pci_driver mlx5_driver;
+
+/*
+ * Reserved UAR address space for TXQ UAR(hw doorbell) mapping, process
+ * local resource used by both primary and secondary to avoid duplicate
+ * reservation.
+ * The space has to be available on both primary and secondary process,
+ * TXQ UAR maps to this area using fixed mmap w/o double check.
+ */
+static void *uar_base;
+
+static int
+find_lower_va_bound(const struct rte_memseg_list *msl __rte_unused,
+ const struct rte_memseg *ms, void *arg)
+{
+ void **addr = arg;
+
+ if (*addr == NULL)
+ *addr = ms->addr;
+ else
+ *addr = RTE_MIN(*addr, ms->addr);
+
+ return 0;
+}
+
+/**
+ * Reserve UAR address space for primary process.
+ *
+ * @param[in] dev
+ * Pointer to Ethernet device.
+ *
+ * @return
+ * 0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_uar_init_primary(struct rte_eth_dev *dev)
+{
+ struct priv *priv = dev->data->dev_private;
+ void *addr = (void *)0;
+
+ if (uar_base) { /* UAR address space mapped. */
+ priv->uar_base = uar_base;
+ return 0;
+ }
+ /* find out lower bound of hugepage segments */
+ rte_memseg_walk(find_lower_va_bound, &addr);
+
+ /* keep distance to hugepages to minimize potential conflicts. */
+ addr = RTE_PTR_SUB(addr, MLX5_UAR_OFFSET + MLX5_UAR_SIZE);
+ /* anonymous mmap, no real memory consumption. */
+ addr = mmap(addr, MLX5_UAR_SIZE,
+ PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (addr == MAP_FAILED) {
+ DRV_LOG(ERR,
+ "port %u failed to reserve UAR address space, please"
+ " adjust MLX5_UAR_SIZE or try --base-virtaddr",
+ dev->data->port_id);
+ rte_errno = ENOMEM;
+ return -rte_errno;
+ }
+ /* Accept either same addr or a new addr returned from mmap if target
+ * range occupied.
+ */
+ DRV_LOG(INFO, "port %u reserved UAR address space: %p",
+ dev->data->port_id, addr);
+ priv->uar_base = addr; /* for primary and secondary UAR re-mmap. */
+ uar_base = addr; /* process local, don't reserve again. */
+ return 0;
+}
+
+/**
+ * Reserve UAR address space for secondary process, align with
+ * primary process.
+ *
+ * @param[in] dev
+ * Pointer to Ethernet device.
+ *
+ * @return
+ * 0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_uar_init_secondary(struct rte_eth_dev *dev)
+{
+ struct priv *priv = dev->data->dev_private;
+ void *addr;
+
+ assert(priv->uar_base);
+ if (uar_base) { /* already reserved. */
+ assert(uar_base == priv->uar_base);
+ return 0;
+ }
+ /* anonymous mmap, no real memory consumption. */
+ addr = mmap(priv->uar_base, MLX5_UAR_SIZE,
+ PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (addr == MAP_FAILED) {
+ DRV_LOG(ERR, "port %u UAR mmap failed: %p size: %llu",
+ dev->data->port_id, priv->uar_base, MLX5_UAR_SIZE);
+ rte_errno = ENXIO;
+ return -rte_errno;
+ }
+ if (priv->uar_base != addr) {
+ DRV_LOG(ERR,
+ "port %u UAR address %p size %llu occupied, please"
+ " adjust MLX5_UAR_OFFSET or try EAL parameter"
+ " --base-virtaddr",
+ dev->data->port_id, priv->uar_base, MLX5_UAR_SIZE);
+ rte_errno = ENXIO;
+ return -rte_errno;
+ }
+ uar_base = addr; /* process local, don't reserve again */
+ DRV_LOG(INFO, "port %u reserved UAR address space: %p",
+ dev->data->port_id, addr);
+ return 0;
+}