Imported Upstream version 16.04
[deb_dpdk.git] / lib / librte_eal / linuxapp / eal / eal_interrupts.c
diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
new file mode 100644 (file)
index 0000000..06b26a9
--- /dev/null
@@ -0,0 +1,1224 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <sys/queue.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <sys/epoll.h>
+#include <sys/signalfd.h>
+#include <sys/ioctl.h>
+#include <sys/eventfd.h>
+#include <assert.h>
+
+#include <rte_common.h>
+#include <rte_interrupts.h>
+#include <rte_memory.h>
+#include <rte_memzone.h>
+#include <rte_launch.h>
+#include <rte_eal.h>
+#include <rte_per_lcore.h>
+#include <rte_lcore.h>
+#include <rte_atomic.h>
+#include <rte_branch_prediction.h>
+#include <rte_ring.h>
+#include <rte_debug.h>
+#include <rte_log.h>
+#include <rte_mempool.h>
+#include <rte_pci.h>
+#include <rte_malloc.h>
+#include <rte_errno.h>
+#include <rte_spinlock.h>
+
+#include "eal_private.h"
+#include "eal_vfio.h"
+#include "eal_thread.h"
+
+#define EAL_INTR_EPOLL_WAIT_FOREVER (-1)
+#define NB_OTHER_INTR               1
+
+static RTE_DEFINE_PER_LCORE(int, _epfd) = -1; /**< epoll fd per thread */
+
+/**
+ * union for pipe fds.
+ */
+union intr_pipefds{
+       struct {
+               int pipefd[2];
+       };
+       struct {
+               int readfd;
+               int writefd;
+       };
+};
+
+/**
+ * union buffer for reading on different devices
+ */
+union rte_intr_read_buffer {
+       int uio_intr_count;              /* for uio device */
+#ifdef VFIO_PRESENT
+       uint64_t vfio_intr_count;        /* for vfio device */
+#endif
+       uint64_t timerfd_num;            /* for timerfd */
+       char charbuf[16];                /* for others */
+};
+
+TAILQ_HEAD(rte_intr_cb_list, rte_intr_callback);
+TAILQ_HEAD(rte_intr_source_list, rte_intr_source);
+
+struct rte_intr_callback {
+       TAILQ_ENTRY(rte_intr_callback) next;
+       rte_intr_callback_fn cb_fn;  /**< callback address */
+       void *cb_arg;                /**< parameter for callback */
+};
+
+struct rte_intr_source {
+       TAILQ_ENTRY(rte_intr_source) next;
+       struct rte_intr_handle intr_handle; /**< interrupt handle */
+       struct rte_intr_cb_list callbacks;  /**< user callbacks */
+       uint32_t active;
+};
+
+/* global spinlock for interrupt data operation */
+static rte_spinlock_t intr_lock = RTE_SPINLOCK_INITIALIZER;
+
+/* union buffer for pipe read/write */
+static union intr_pipefds intr_pipe;
+
+/* interrupt sources list */
+static struct rte_intr_source_list intr_sources;
+
+/* interrupt handling thread */
+static pthread_t intr_thread;
+
+/* VFIO interrupts */
+#ifdef VFIO_PRESENT
+
+#define IRQ_SET_BUF_LEN  (sizeof(struct vfio_irq_set) + sizeof(int))
+/* irq set buffer length for queue interrupts and LSC interrupt */
+#define MSIX_IRQ_SET_BUF_LEN (sizeof(struct vfio_irq_set) + \
+                             sizeof(int) * (RTE_MAX_RXTX_INTR_VEC_ID + 1))
+
+/* enable legacy (INTx) interrupts */
+static int
+vfio_enable_intx(struct rte_intr_handle *intr_handle) {
+       struct vfio_irq_set *irq_set;
+       char irq_set_buf[IRQ_SET_BUF_LEN];
+       int len, ret;
+       int *fd_ptr;
+
+       len = sizeof(irq_set_buf);
+
+       /* enable INTx */
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       irq_set->count = 1;
+       irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
+       irq_set->start = 0;
+       fd_ptr = (int *) &irq_set->data;
+       *fd_ptr = intr_handle->fd;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Error enabling INTx interrupts for fd %d\n",
+                                               intr_handle->fd);
+               return -1;
+       }
+
+       /* unmask INTx after enabling */
+       memset(irq_set, 0, len);
+       len = sizeof(struct vfio_irq_set);
+       irq_set->argsz = len;
+       irq_set->count = 1;
+       irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK;
+       irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
+       irq_set->start = 0;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Error unmasking INTx interrupts for fd %d\n",
+                                               intr_handle->fd);
+               return -1;
+       }
+       return 0;
+}
+
+/* disable legacy (INTx) interrupts */
+static int
+vfio_disable_intx(struct rte_intr_handle *intr_handle) {
+       struct vfio_irq_set *irq_set;
+       char irq_set_buf[IRQ_SET_BUF_LEN];
+       int len, ret;
+
+       len = sizeof(struct vfio_irq_set);
+
+       /* mask interrupts before disabling */
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       irq_set->count = 1;
+       irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK;
+       irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
+       irq_set->start = 0;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Error unmasking INTx interrupts for fd %d\n",
+                                               intr_handle->fd);
+               return -1;
+       }
+
+       /* disable INTx*/
+       memset(irq_set, 0, len);
+       irq_set->argsz = len;
+       irq_set->count = 0;
+       irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
+       irq_set->start = 0;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL,
+                       "Error disabling INTx interrupts for fd %d\n", intr_handle->fd);
+               return -1;
+       }
+       return 0;
+}
+
+/* enable MSI interrupts */
+static int
+vfio_enable_msi(struct rte_intr_handle *intr_handle) {
+       int len, ret;
+       char irq_set_buf[IRQ_SET_BUF_LEN];
+       struct vfio_irq_set *irq_set;
+       int *fd_ptr;
+
+       len = sizeof(irq_set_buf);
+
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       irq_set->count = 1;
+       irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_MSI_IRQ_INDEX;
+       irq_set->start = 0;
+       fd_ptr = (int *) &irq_set->data;
+       *fd_ptr = intr_handle->fd;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Error enabling MSI interrupts for fd %d\n",
+                                               intr_handle->fd);
+               return -1;
+       }
+       return 0;
+}
+
+/* disable MSI interrupts */
+static int
+vfio_disable_msi(struct rte_intr_handle *intr_handle) {
+       struct vfio_irq_set *irq_set;
+       char irq_set_buf[IRQ_SET_BUF_LEN];
+       int len, ret;
+
+       len = sizeof(struct vfio_irq_set);
+
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       irq_set->count = 0;
+       irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_MSI_IRQ_INDEX;
+       irq_set->start = 0;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret)
+               RTE_LOG(ERR, EAL,
+                       "Error disabling MSI interrupts for fd %d\n", intr_handle->fd);
+
+       return ret;
+}
+
+/* enable MSI-X interrupts */
+static int
+vfio_enable_msix(struct rte_intr_handle *intr_handle) {
+       int len, ret;
+       char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
+       struct vfio_irq_set *irq_set;
+       int *fd_ptr;
+
+       len = sizeof(irq_set_buf);
+
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       if (!intr_handle->max_intr)
+               intr_handle->max_intr = 1;
+       else if (intr_handle->max_intr > RTE_MAX_RXTX_INTR_VEC_ID)
+               intr_handle->max_intr = RTE_MAX_RXTX_INTR_VEC_ID + 1;
+
+       irq_set->count = intr_handle->max_intr;
+       irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
+       irq_set->start = 0;
+       fd_ptr = (int *) &irq_set->data;
+       /* INTR vector offset 0 reserve for non-efds mapping */
+       fd_ptr[RTE_INTR_VEC_ZERO_OFFSET] = intr_handle->fd;
+       memcpy(&fd_ptr[RTE_INTR_VEC_RXTX_OFFSET], intr_handle->efds,
+               sizeof(*intr_handle->efds) * intr_handle->nb_efd);
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Error enabling MSI-X interrupts for fd %d\n",
+                                               intr_handle->fd);
+               return -1;
+       }
+
+       return 0;
+}
+
+/* disable MSI-X interrupts */
+static int
+vfio_disable_msix(struct rte_intr_handle *intr_handle) {
+       struct vfio_irq_set *irq_set;
+       char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
+       int len, ret;
+
+       len = sizeof(struct vfio_irq_set);
+
+       irq_set = (struct vfio_irq_set *) irq_set_buf;
+       irq_set->argsz = len;
+       irq_set->count = 0;
+       irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
+       irq_set->start = 0;
+
+       ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+       if (ret)
+               RTE_LOG(ERR, EAL,
+                       "Error disabling MSI-X interrupts for fd %d\n", intr_handle->fd);
+
+       return ret;
+}
+#endif
+
+static int
+uio_intx_intr_disable(struct rte_intr_handle *intr_handle)
+{
+       unsigned char command_high;
+
+       /* use UIO config file descriptor for uio_pci_generic */
+       if (pread(intr_handle->uio_cfg_fd, &command_high, 1, 5) != 1) {
+               RTE_LOG(ERR, EAL,
+                       "Error reading interrupts status for fd %d\n",
+                       intr_handle->uio_cfg_fd);
+               return -1;
+       }
+       /* disable interrupts */
+       command_high |= 0x4;
+       if (pwrite(intr_handle->uio_cfg_fd, &command_high, 1, 5) != 1) {
+               RTE_LOG(ERR, EAL,
+                       "Error disabling interrupts for fd %d\n",
+                       intr_handle->uio_cfg_fd);
+               return -1;
+       }
+
+       return 0;
+}
+
+static int
+uio_intx_intr_enable(struct rte_intr_handle *intr_handle)
+{
+       unsigned char command_high;
+
+       /* use UIO config file descriptor for uio_pci_generic */
+       if (pread(intr_handle->uio_cfg_fd, &command_high, 1, 5) != 1) {
+               RTE_LOG(ERR, EAL,
+                       "Error reading interrupts status for fd %d\n",
+                       intr_handle->uio_cfg_fd);
+               return -1;
+       }
+       /* enable interrupts */
+       command_high &= ~0x4;
+       if (pwrite(intr_handle->uio_cfg_fd, &command_high, 1, 5) != 1) {
+               RTE_LOG(ERR, EAL,
+                       "Error enabling interrupts for fd %d\n",
+                       intr_handle->uio_cfg_fd);
+               return -1;
+       }
+
+       return 0;
+}
+
+static int
+uio_intr_disable(struct rte_intr_handle *intr_handle)
+{
+       const int value = 0;
+
+       if (write(intr_handle->fd, &value, sizeof(value)) < 0) {
+               RTE_LOG(ERR, EAL,
+                       "Error disabling interrupts for fd %d (%s)\n",
+                       intr_handle->fd, strerror(errno));
+               return -1;
+       }
+       return 0;
+}
+
+static int
+uio_intr_enable(struct rte_intr_handle *intr_handle)
+{
+       const int value = 1;
+
+       if (write(intr_handle->fd, &value, sizeof(value)) < 0) {
+               RTE_LOG(ERR, EAL,
+                       "Error enabling interrupts for fd %d (%s)\n",
+                       intr_handle->fd, strerror(errno));
+               return -1;
+       }
+       return 0;
+}
+
+int
+rte_intr_callback_register(struct rte_intr_handle *intr_handle,
+                       rte_intr_callback_fn cb, void *cb_arg)
+{
+       int ret, wake_thread;
+       struct rte_intr_source *src;
+       struct rte_intr_callback *callback;
+
+       wake_thread = 0;
+
+       /* first do parameter checking */
+       if (intr_handle == NULL || intr_handle->fd < 0 || cb == NULL) {
+               RTE_LOG(ERR, EAL,
+                       "Registering with invalid input parameter\n");
+               return -EINVAL;
+       }
+
+       /* allocate a new interrupt callback entity */
+       callback = rte_zmalloc("interrupt callback list",
+                               sizeof(*callback), 0);
+       if (callback == NULL) {
+               RTE_LOG(ERR, EAL, "Can not allocate memory\n");
+               return -ENOMEM;
+       }
+       callback->cb_fn = cb;
+       callback->cb_arg = cb_arg;
+
+       rte_spinlock_lock(&intr_lock);
+
+       /* check if there is at least one callback registered for the fd */
+       TAILQ_FOREACH(src, &intr_sources, next) {
+               if (src->intr_handle.fd == intr_handle->fd) {
+                       /* we had no interrupts for this */
+                       if TAILQ_EMPTY(&src->callbacks)
+                               wake_thread = 1;
+
+                       TAILQ_INSERT_TAIL(&(src->callbacks), callback, next);
+                       ret = 0;
+                       break;
+               }
+       }
+
+       /* no existing callbacks for this - add new source */
+       if (src == NULL) {
+               if ((src = rte_zmalloc("interrupt source list",
+                               sizeof(*src), 0)) == NULL) {
+                       RTE_LOG(ERR, EAL, "Can not allocate memory\n");
+                       rte_free(callback);
+                       ret = -ENOMEM;
+               } else {
+                       src->intr_handle = *intr_handle;
+                       TAILQ_INIT(&src->callbacks);
+                       TAILQ_INSERT_TAIL(&(src->callbacks), callback, next);
+                       TAILQ_INSERT_TAIL(&intr_sources, src, next);
+                       wake_thread = 1;
+                       ret = 0;
+               }
+       }
+
+       rte_spinlock_unlock(&intr_lock);
+
+       /**
+        * check if need to notify the pipe fd waited by epoll_wait to
+        * rebuild the wait list.
+        */
+       if (wake_thread)
+               if (write(intr_pipe.writefd, "1", 1) < 0)
+                       return -EPIPE;
+
+       return ret;
+}
+
+int
+rte_intr_callback_unregister(struct rte_intr_handle *intr_handle,
+                       rte_intr_callback_fn cb_fn, void *cb_arg)
+{
+       int ret;
+       struct rte_intr_source *src;
+       struct rte_intr_callback *cb, *next;
+
+       /* do parameter checking first */
+       if (intr_handle == NULL || intr_handle->fd < 0) {
+               RTE_LOG(ERR, EAL,
+               "Unregistering with invalid input parameter\n");
+               return -EINVAL;
+       }
+
+       rte_spinlock_lock(&intr_lock);
+
+       /* check if the insterrupt source for the fd is existent */
+       TAILQ_FOREACH(src, &intr_sources, next)
+               if (src->intr_handle.fd == intr_handle->fd)
+                       break;
+
+       /* No interrupt source registered for the fd */
+       if (src == NULL) {
+               ret = -ENOENT;
+
+       /* interrupt source has some active callbacks right now. */
+       } else if (src->active != 0) {
+               ret = -EAGAIN;
+
+       /* ok to remove. */
+       } else {
+               ret = 0;
+
+               /*walk through the callbacks and remove all that match. */
+               for (cb = TAILQ_FIRST(&src->callbacks); cb != NULL; cb = next) {
+
+                       next = TAILQ_NEXT(cb, next);
+
+                       if (cb->cb_fn == cb_fn && (cb_arg == (void *)-1 ||
+                                       cb->cb_arg == cb_arg)) {
+                               TAILQ_REMOVE(&src->callbacks, cb, next);
+                               rte_free(cb);
+                               ret++;
+                       }
+               }
+
+               /* all callbacks for that source are removed. */
+               if (TAILQ_EMPTY(&src->callbacks)) {
+                       TAILQ_REMOVE(&intr_sources, src, next);
+                       rte_free(src);
+               }
+       }
+
+       rte_spinlock_unlock(&intr_lock);
+
+       /* notify the pipe fd waited by epoll_wait to rebuild the wait list */
+       if (ret >= 0 && write(intr_pipe.writefd, "1", 1) < 0) {
+               ret = -EPIPE;
+       }
+
+       return ret;
+}
+
+int
+rte_intr_enable(struct rte_intr_handle *intr_handle)
+{
+       if (!intr_handle || intr_handle->fd < 0 || intr_handle->uio_cfg_fd < 0)
+               return -1;
+
+       switch (intr_handle->type){
+       /* write to the uio fd to enable the interrupt */
+       case RTE_INTR_HANDLE_UIO:
+               if (uio_intr_enable(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_UIO_INTX:
+               if (uio_intx_intr_enable(intr_handle))
+                       return -1;
+               break;
+       /* not used at this moment */
+       case RTE_INTR_HANDLE_ALARM:
+               return -1;
+#ifdef VFIO_PRESENT
+       case RTE_INTR_HANDLE_VFIO_MSIX:
+               if (vfio_enable_msix(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_VFIO_MSI:
+               if (vfio_enable_msi(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_VFIO_LEGACY:
+               if (vfio_enable_intx(intr_handle))
+                       return -1;
+               break;
+#endif
+       /* unknown handle type */
+       default:
+               RTE_LOG(ERR, EAL,
+                       "Unknown handle type of fd %d\n",
+                                       intr_handle->fd);
+               return -1;
+       }
+
+       return 0;
+}
+
+int
+rte_intr_disable(struct rte_intr_handle *intr_handle)
+{
+       if (!intr_handle || intr_handle->fd < 0 || intr_handle->uio_cfg_fd < 0)
+               return -1;
+
+       switch (intr_handle->type){
+       /* write to the uio fd to disable the interrupt */
+       case RTE_INTR_HANDLE_UIO:
+               if (uio_intr_disable(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_UIO_INTX:
+               if (uio_intx_intr_disable(intr_handle))
+                       return -1;
+               break;
+       /* not used at this moment */
+       case RTE_INTR_HANDLE_ALARM:
+               return -1;
+#ifdef VFIO_PRESENT
+       case RTE_INTR_HANDLE_VFIO_MSIX:
+               if (vfio_disable_msix(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_VFIO_MSI:
+               if (vfio_disable_msi(intr_handle))
+                       return -1;
+               break;
+       case RTE_INTR_HANDLE_VFIO_LEGACY:
+               if (vfio_disable_intx(intr_handle))
+                       return -1;
+               break;
+#endif
+       /* unknown handle type */
+       default:
+               RTE_LOG(ERR, EAL,
+                       "Unknown handle type of fd %d\n",
+                                       intr_handle->fd);
+               return -1;
+       }
+
+       return 0;
+}
+
+static int
+eal_intr_process_interrupts(struct epoll_event *events, int nfds)
+{
+       int n, bytes_read;
+       struct rte_intr_source *src;
+       struct rte_intr_callback *cb;
+       union rte_intr_read_buffer buf;
+       struct rte_intr_callback active_cb;
+
+       for (n = 0; n < nfds; n++) {
+
+               /**
+                * if the pipe fd is ready to read, return out to
+                * rebuild the wait list.
+                */
+               if (events[n].data.fd == intr_pipe.readfd){
+                       int r = read(intr_pipe.readfd, buf.charbuf,
+                                       sizeof(buf.charbuf));
+                       RTE_SET_USED(r);
+                       return -1;
+               }
+               rte_spinlock_lock(&intr_lock);
+               TAILQ_FOREACH(src, &intr_sources, next)
+                       if (src->intr_handle.fd ==
+                                       events[n].data.fd)
+                               break;
+               if (src == NULL){
+                       rte_spinlock_unlock(&intr_lock);
+                       continue;
+               }
+
+               /* mark this interrupt source as active and release the lock. */
+               src->active = 1;
+               rte_spinlock_unlock(&intr_lock);
+
+               /* set the length to be read dor different handle type */
+               switch (src->intr_handle.type) {
+               case RTE_INTR_HANDLE_UIO:
+               case RTE_INTR_HANDLE_UIO_INTX:
+                       bytes_read = sizeof(buf.uio_intr_count);
+                       break;
+               case RTE_INTR_HANDLE_ALARM:
+                       bytes_read = sizeof(buf.timerfd_num);
+                       break;
+#ifdef VFIO_PRESENT
+               case RTE_INTR_HANDLE_VFIO_MSIX:
+               case RTE_INTR_HANDLE_VFIO_MSI:
+               case RTE_INTR_HANDLE_VFIO_LEGACY:
+                       bytes_read = sizeof(buf.vfio_intr_count);
+                       break;
+#endif
+               case RTE_INTR_HANDLE_EXT:
+               default:
+                       bytes_read = 1;
+                       break;
+               }
+
+               if (src->intr_handle.type != RTE_INTR_HANDLE_EXT) {
+                       /**
+                        * read out to clear the ready-to-be-read flag
+                        * for epoll_wait.
+                        */
+                       bytes_read = read(events[n].data.fd, &buf, bytes_read);
+                       if (bytes_read < 0) {
+                               if (errno == EINTR || errno == EWOULDBLOCK)
+                                       continue;
+
+                               RTE_LOG(ERR, EAL, "Error reading from file "
+                                       "descriptor %d: %s\n",
+                                       events[n].data.fd,
+                                       strerror(errno));
+                       } else if (bytes_read == 0)
+                               RTE_LOG(ERR, EAL, "Read nothing from file "
+                                       "descriptor %d\n", events[n].data.fd);
+               }
+
+               /* grab a lock, again to call callbacks and update status. */
+               rte_spinlock_lock(&intr_lock);
+
+               if (bytes_read > 0) {
+
+                       /* Finally, call all callbacks. */
+                       TAILQ_FOREACH(cb, &src->callbacks, next) {
+
+                               /* make a copy and unlock. */
+                               active_cb = *cb;
+                               rte_spinlock_unlock(&intr_lock);
+
+                               /* call the actual callback */
+                               active_cb.cb_fn(&src->intr_handle,
+                                       active_cb.cb_arg);
+
+                               /*get the lock back. */
+                               rte_spinlock_lock(&intr_lock);
+                       }
+               }
+
+               /* we done with that interrupt source, release it. */
+               src->active = 0;
+               rte_spinlock_unlock(&intr_lock);
+       }
+
+       return 0;
+}
+
+/**
+ * It handles all the interrupts.
+ *
+ * @param pfd
+ *  epoll file descriptor.
+ * @param totalfds
+ *  The number of file descriptors added in epoll.
+ *
+ * @return
+ *  void
+ */
+static void
+eal_intr_handle_interrupts(int pfd, unsigned totalfds)
+{
+       struct epoll_event events[totalfds];
+       int nfds = 0;
+
+       for(;;) {
+               nfds = epoll_wait(pfd, events, totalfds,
+                       EAL_INTR_EPOLL_WAIT_FOREVER);
+               /* epoll_wait fail */
+               if (nfds < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       RTE_LOG(ERR, EAL,
+                               "epoll_wait returns with fail\n");
+                       return;
+               }
+               /* epoll_wait timeout, will never happens here */
+               else if (nfds == 0)
+                       continue;
+               /* epoll_wait has at least one fd ready to read */
+               if (eal_intr_process_interrupts(events, nfds) < 0)
+                       return;
+       }
+}
+
+/**
+ * It builds/rebuilds up the epoll file descriptor with all the
+ * file descriptors being waited on. Then handles the interrupts.
+ *
+ * @param arg
+ *  pointer. (unused)
+ *
+ * @return
+ *  never return;
+ */
+static __attribute__((noreturn)) void *
+eal_intr_thread_main(__rte_unused void *arg)
+{
+       struct epoll_event ev;
+
+       /* host thread, never break out */
+       for (;;) {
+               /* build up the epoll fd with all descriptors we are to
+                * wait on then pass it to the handle_interrupts function
+                */
+               static struct epoll_event pipe_event = {
+                       .events = EPOLLIN | EPOLLPRI,
+               };
+               struct rte_intr_source *src;
+               unsigned numfds = 0;
+
+               /* create epoll fd */
+               int pfd = epoll_create(1);
+               if (pfd < 0)
+                       rte_panic("Cannot create epoll instance\n");
+
+               pipe_event.data.fd = intr_pipe.readfd;
+               /**
+                * add pipe fd into wait list, this pipe is used to
+                * rebuild the wait list.
+                */
+               if (epoll_ctl(pfd, EPOLL_CTL_ADD, intr_pipe.readfd,
+                                               &pipe_event) < 0) {
+                       rte_panic("Error adding fd to %d epoll_ctl, %s\n",
+                                       intr_pipe.readfd, strerror(errno));
+               }
+               numfds++;
+
+               rte_spinlock_lock(&intr_lock);
+
+               TAILQ_FOREACH(src, &intr_sources, next) {
+                       if (src->callbacks.tqh_first == NULL)
+                               continue; /* skip those with no callbacks */
+                       ev.events = EPOLLIN | EPOLLPRI;
+                       ev.data.fd = src->intr_handle.fd;
+
+                       /**
+                        * add all the uio device file descriptor
+                        * into wait list.
+                        */
+                       if (epoll_ctl(pfd, EPOLL_CTL_ADD,
+                                       src->intr_handle.fd, &ev) < 0){
+                               rte_panic("Error adding fd %d epoll_ctl, %s\n",
+                                       src->intr_handle.fd, strerror(errno));
+                       }
+                       else
+                               numfds++;
+               }
+               rte_spinlock_unlock(&intr_lock);
+               /* serve the interrupt */
+               eal_intr_handle_interrupts(pfd, numfds);
+
+               /**
+                * when we return, we need to rebuild the
+                * list of fds to monitor.
+                */
+               close(pfd);
+       }
+}
+
+int
+rte_eal_intr_init(void)
+{
+       int ret = 0, ret_1 = 0;
+       char thread_name[RTE_MAX_THREAD_NAME_LEN];
+
+       /* init the global interrupt source head */
+       TAILQ_INIT(&intr_sources);
+
+       /**
+        * create a pipe which will be waited by epoll and notified to
+        * rebuild the wait list of epoll.
+        */
+       if (pipe(intr_pipe.pipefd) < 0)
+               return -1;
+
+       /* create the host thread to wait/handle the interrupt */
+       ret = pthread_create(&intr_thread, NULL,
+                       eal_intr_thread_main, NULL);
+       if (ret != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to create thread for interrupt handling\n");
+       } else {
+               /* Set thread_name for aid in debugging. */
+               snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN,
+                       "eal-intr-thread");
+               ret_1 = rte_thread_setname(intr_thread, thread_name);
+               if (ret_1 != 0)
+                       RTE_LOG(ERR, EAL,
+                       "Failed to set thread name for interrupt handling\n");
+       }
+
+       return -ret;
+}
+
+static void
+eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
+{
+       union rte_intr_read_buffer buf;
+       int bytes_read = 1;
+       int nbytes;
+
+       switch (intr_handle->type) {
+       case RTE_INTR_HANDLE_UIO:
+       case RTE_INTR_HANDLE_UIO_INTX:
+               bytes_read = sizeof(buf.uio_intr_count);
+               break;
+#ifdef VFIO_PRESENT
+       case RTE_INTR_HANDLE_VFIO_MSIX:
+       case RTE_INTR_HANDLE_VFIO_MSI:
+       case RTE_INTR_HANDLE_VFIO_LEGACY:
+               bytes_read = sizeof(buf.vfio_intr_count);
+               break;
+#endif
+       default:
+               bytes_read = 1;
+               RTE_LOG(INFO, EAL, "unexpected intr type\n");
+               break;
+       }
+
+       /**
+        * read out to clear the ready-to-be-read flag
+        * for epoll_wait.
+        */
+       do {
+               nbytes = read(fd, &buf, bytes_read);
+               if (nbytes < 0) {
+                       if (errno == EINTR || errno == EWOULDBLOCK ||
+                           errno == EAGAIN)
+                               continue;
+                       RTE_LOG(ERR, EAL,
+                               "Error reading from fd %d: %s\n",
+                               fd, strerror(errno));
+               } else if (nbytes == 0)
+                       RTE_LOG(ERR, EAL, "Read nothing from fd %d\n", fd);
+               return;
+       } while (1);
+}
+
+static int
+eal_epoll_process_event(struct epoll_event *evs, unsigned int n,
+                       struct rte_epoll_event *events)
+{
+       unsigned int i, count = 0;
+       struct rte_epoll_event *rev;
+
+       for (i = 0; i < n; i++) {
+               rev = evs[i].data.ptr;
+               if (!rev || !rte_atomic32_cmpset(&rev->status, RTE_EPOLL_VALID,
+                                                RTE_EPOLL_EXEC))
+                       continue;
+
+               events[count].status        = RTE_EPOLL_VALID;
+               events[count].fd            = rev->fd;
+               events[count].epfd          = rev->epfd;
+               events[count].epdata.event  = rev->epdata.event;
+               events[count].epdata.data   = rev->epdata.data;
+               if (rev->epdata.cb_fun)
+                       rev->epdata.cb_fun(rev->fd,
+                                          rev->epdata.cb_arg);
+
+               rte_compiler_barrier();
+               rev->status = RTE_EPOLL_VALID;
+               count++;
+       }
+       return count;
+}
+
+static inline int
+eal_init_tls_epfd(void)
+{
+       int pfd = epoll_create(255);
+
+       if (pfd < 0) {
+               RTE_LOG(ERR, EAL,
+                       "Cannot create epoll instance\n");
+               return -1;
+       }
+       return pfd;
+}
+
+int
+rte_intr_tls_epfd(void)
+{
+       if (RTE_PER_LCORE(_epfd) == -1)
+               RTE_PER_LCORE(_epfd) = eal_init_tls_epfd();
+
+       return RTE_PER_LCORE(_epfd);
+}
+
+int
+rte_epoll_wait(int epfd, struct rte_epoll_event *events,
+              int maxevents, int timeout)
+{
+       struct epoll_event evs[maxevents];
+       int rc;
+
+       if (!events) {
+               RTE_LOG(ERR, EAL, "rte_epoll_event can't be NULL\n");
+               return -1;
+       }
+
+       /* using per thread epoll fd */
+       if (epfd == RTE_EPOLL_PER_THREAD)
+               epfd = rte_intr_tls_epfd();
+
+       while (1) {
+               rc = epoll_wait(epfd, evs, maxevents, timeout);
+               if (likely(rc > 0)) {
+                       /* epoll_wait has at least one fd ready to read */
+                       rc = eal_epoll_process_event(evs, rc, events);
+                       break;
+               } else if (rc < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       /* epoll_wait fail */
+                       RTE_LOG(ERR, EAL, "epoll_wait returns with fail %s\n",
+                               strerror(errno));
+                       rc = -1;
+                       break;
+               } else {
+                       /* rc == 0, epoll_wait timed out */
+                       break;
+               }
+       }
+
+       return rc;
+}
+
+static inline void
+eal_epoll_data_safe_free(struct rte_epoll_event *ev)
+{
+       while (!rte_atomic32_cmpset(&ev->status, RTE_EPOLL_VALID,
+                                   RTE_EPOLL_INVALID))
+               while (ev->status != RTE_EPOLL_VALID)
+                       rte_pause();
+       memset(&ev->epdata, 0, sizeof(ev->epdata));
+       ev->fd = -1;
+       ev->epfd = -1;
+}
+
+int
+rte_epoll_ctl(int epfd, int op, int fd,
+             struct rte_epoll_event *event)
+{
+       struct epoll_event ev;
+
+       if (!event) {
+               RTE_LOG(ERR, EAL, "rte_epoll_event can't be NULL\n");
+               return -1;
+       }
+
+       /* using per thread epoll fd */
+       if (epfd == RTE_EPOLL_PER_THREAD)
+               epfd = rte_intr_tls_epfd();
+
+       if (op == EPOLL_CTL_ADD) {
+               event->status = RTE_EPOLL_VALID;
+               event->fd = fd;  /* ignore fd in event */
+               event->epfd = epfd;
+               ev.data.ptr = (void *)event;
+       }
+
+       ev.events = event->epdata.event;
+       if (epoll_ctl(epfd, op, fd, &ev) < 0) {
+               RTE_LOG(ERR, EAL, "Error op %d fd %d epoll_ctl, %s\n",
+                       op, fd, strerror(errno));
+               if (op == EPOLL_CTL_ADD)
+                       /* rollback status when CTL_ADD fail */
+                       event->status = RTE_EPOLL_INVALID;
+               return -1;
+       }
+
+       if (op == EPOLL_CTL_DEL && event->status != RTE_EPOLL_INVALID)
+               eal_epoll_data_safe_free(event);
+
+       return 0;
+}
+
+int
+rte_intr_rx_ctl(struct rte_intr_handle *intr_handle, int epfd,
+               int op, unsigned int vec, void *data)
+{
+       struct rte_epoll_event *rev;
+       struct rte_epoll_data *epdata;
+       int epfd_op;
+       unsigned int efd_idx;
+       int rc = 0;
+
+       efd_idx = (vec >= RTE_INTR_VEC_RXTX_OFFSET) ?
+               (vec - RTE_INTR_VEC_RXTX_OFFSET) : vec;
+
+       if (!intr_handle || intr_handle->nb_efd == 0 ||
+           efd_idx >= intr_handle->nb_efd) {
+               RTE_LOG(ERR, EAL, "Wrong intr vector number.\n");
+               return -EPERM;
+       }
+
+       switch (op) {
+       case RTE_INTR_EVENT_ADD:
+               epfd_op = EPOLL_CTL_ADD;
+               rev = &intr_handle->elist[efd_idx];
+               if (rev->status != RTE_EPOLL_INVALID) {
+                       RTE_LOG(INFO, EAL, "Event already been added.\n");
+                       return -EEXIST;
+               }
+
+               /* attach to intr vector fd */
+               epdata = &rev->epdata;
+               epdata->event  = EPOLLIN | EPOLLPRI | EPOLLET;
+               epdata->data   = data;
+               epdata->cb_fun = (rte_intr_event_cb_t)eal_intr_proc_rxtx_intr;
+               epdata->cb_arg = (void *)intr_handle;
+               rc = rte_epoll_ctl(epfd, epfd_op,
+                                  intr_handle->efds[efd_idx], rev);
+               if (!rc)
+                       RTE_LOG(DEBUG, EAL,
+                               "efd %d associated with vec %d added on epfd %d"
+                               "\n", rev->fd, vec, epfd);
+               else
+                       rc = -EPERM;
+               break;
+       case RTE_INTR_EVENT_DEL:
+               epfd_op = EPOLL_CTL_DEL;
+               rev = &intr_handle->elist[efd_idx];
+               if (rev->status == RTE_EPOLL_INVALID) {
+                       RTE_LOG(INFO, EAL, "Event does not exist.\n");
+                       return -EPERM;
+               }
+
+               rc = rte_epoll_ctl(rev->epfd, epfd_op, rev->fd, rev);
+               if (rc)
+                       rc = -EPERM;
+               break;
+       default:
+               RTE_LOG(ERR, EAL, "event op type mismatch\n");
+               rc = -EPERM;
+       }
+
+       return rc;
+}
+
+int
+rte_intr_efd_enable(struct rte_intr_handle *intr_handle, uint32_t nb_efd)
+{
+       uint32_t i;
+       int fd;
+       uint32_t n = RTE_MIN(nb_efd, (uint32_t)RTE_MAX_RXTX_INTR_VEC_ID);
+
+       assert(nb_efd != 0);
+
+       if (intr_handle->type == RTE_INTR_HANDLE_VFIO_MSIX) {
+               for (i = 0; i < n; i++) {
+                       fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+                       if (fd < 0) {
+                               RTE_LOG(ERR, EAL,
+                                       "can't setup eventfd, error %i (%s)\n",
+                                       errno, strerror(errno));
+                               return -1;
+                       }
+                       intr_handle->efds[i] = fd;
+               }
+               intr_handle->nb_efd   = n;
+               intr_handle->max_intr = NB_OTHER_INTR + n;
+       } else {
+               intr_handle->efds[0]  = intr_handle->fd;
+               intr_handle->nb_efd   = RTE_MIN(nb_efd, 1U);
+               intr_handle->max_intr = NB_OTHER_INTR;
+       }
+
+       return 0;
+}
+
+void
+rte_intr_efd_disable(struct rte_intr_handle *intr_handle)
+{
+       uint32_t i;
+       struct rte_epoll_event *rev;
+
+       for (i = 0; i < intr_handle->nb_efd; i++) {
+               rev = &intr_handle->elist[i];
+               if (rev->status == RTE_EPOLL_INVALID)
+                       continue;
+               if (rte_epoll_ctl(rev->epfd, EPOLL_CTL_DEL, rev->fd, rev)) {
+                       /* force free if the entry valid */
+                       eal_epoll_data_safe_free(rev);
+                       rev->status = RTE_EPOLL_INVALID;
+               }
+       }
+
+       if (intr_handle->max_intr > intr_handle->nb_efd) {
+               for (i = 0; i < intr_handle->nb_efd; i++)
+                       close(intr_handle->efds[i]);
+       }
+       intr_handle->nb_efd = 0;
+       intr_handle->max_intr = 0;
+}
+
+int
+rte_intr_dp_is_en(struct rte_intr_handle *intr_handle)
+{
+       return !(!intr_handle->nb_efd);
+}
+
+int
+rte_intr_allow_others(struct rte_intr_handle *intr_handle)
+{
+       if (!rte_intr_dp_is_en(intr_handle))
+               return 1;
+       else
+               return !!(intr_handle->max_intr - intr_handle->nb_efd);
+}
+
+int
+rte_intr_cap_multiple(struct rte_intr_handle *intr_handle)
+{
+       if (intr_handle->type == RTE_INTR_HANDLE_VFIO_MSIX)
+               return 1;
+
+       return 0;
+}