vdpa/ifc: add interrupt handling for config space

Create a thread to poll and relay config space change interrupt.
Use VHOST_USER_SLAVE_CONFIG_CHANGE_MSG to inform QEMU.

Signed-off-by: Andy Pei <andy.pei@intel.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

diff --git a/drivers/vdpa/ifc/ifcvf_vdpa.c b/drivers/vdpa/ifc/ifcvf_vdpa.c
index 30850b0b348a62516e59505af85b652674ad194e..40a18b250754057f60d78ad7e86bd2b82c664c7e 100644 (file)
--- a/drivers/vdpa/ifc/ifcvf_vdpa.c
+++ b/drivers/vdpa/ifc/ifcvf_vdpa.c
@@ -53,7 +53,9 @@ struct ifcvf_internal {
        int vfio_group_fd;
        int vfio_dev_fd;
        pthread_t tid;  /* thread for notify relay */
+       pthread_t intr_tid; /* thread for config space change interrupt relay */
        int epfd;
+       int csc_epfd;
        int vid;
        struct rte_vdpa_device *vdev;
        uint16_t max_queues;
@@ -566,6 +568,114 @@ unset_notify_relay(struct ifcvf_internal *internal)
        return 0;
 }
 
+static void
+virtio_interrupt_handler(struct ifcvf_internal *internal)
+{
+       int vid = internal->vid;
+       int ret;
+
+       ret = rte_vhost_slave_config_change(vid, 1);
+       if (ret)
+               DRV_LOG(ERR, "failed to notify the guest about configuration space change.");
+}
+
+static void *
+intr_relay(void *arg)
+{
+       struct ifcvf_internal *internal = (struct ifcvf_internal *)arg;
+       struct epoll_event csc_event;
+       struct epoll_event ev;
+       uint64_t buf;
+       int nbytes;
+       int csc_epfd, csc_val = 0;
+
+       csc_epfd = epoll_create(1);
+       if (csc_epfd < 0) {
+               DRV_LOG(ERR, "failed to create epoll for config space change.");
+               return NULL;
+       }
+
+       ev.events = EPOLLIN | EPOLLPRI | EPOLLRDHUP | EPOLLHUP;
+       ev.data.fd = rte_intr_fd_get(internal->pdev->intr_handle);
+       if (epoll_ctl(csc_epfd, EPOLL_CTL_ADD,
+               rte_intr_fd_get(internal->pdev->intr_handle), &ev) < 0) {
+               DRV_LOG(ERR, "epoll add error: %s", strerror(errno));
+               goto out;
+       }
+
+       internal->csc_epfd = csc_epfd;
+
+       for (;;) {
+               csc_val = epoll_wait(csc_epfd, &csc_event, 1, -1);
+               if (csc_val < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       DRV_LOG(ERR, "epoll_wait return fail.");
+                       goto out;
+               } else if (csc_val == 0) {
+                       continue;
+               } else {
+                       /* csc_val > 0 */
+                       nbytes = read(csc_event.data.fd, &buf, 8);
+                       if (nbytes < 0) {
+                               if (errno == EINTR ||
+                                   errno == EWOULDBLOCK ||
+                                   errno == EAGAIN)
+                                       continue;
+                               DRV_LOG(ERR, "Error reading from file descriptor %d: %s\n",
+                                       csc_event.data.fd,
+                                       strerror(errno));
+                               goto out;
+                       } else if (nbytes == 0) {
+                               DRV_LOG(ERR, "Read nothing from file descriptor %d\n",
+                                       csc_event.data.fd);
+                               continue;
+                       } else {
+                               virtio_interrupt_handler(internal);
+                       }
+               }
+       }
+
+out:
+       if (csc_epfd >= 0)
+               close(csc_epfd);
+       internal->csc_epfd = -1;
+
+       return NULL;
+}
+
+static int
+setup_intr_relay(struct ifcvf_internal *internal)
+{
+       char name[THREAD_NAME_LEN];
+       int ret;
+
+       snprintf(name, sizeof(name), "ifc-intr-%d", internal->vid);
+       ret = rte_ctrl_thread_create(&internal->intr_tid, name, NULL,
+                                    intr_relay, (void *)internal);
+       if (ret) {
+               DRV_LOG(ERR, "failed to create notify relay pthread.");
+               return -1;
+       }
+       return 0;
+}
+
+static void
+unset_intr_relay(struct ifcvf_internal *internal)
+{
+       void *status;
+
+       if (internal->intr_tid) {
+               pthread_cancel(internal->intr_tid);
+               pthread_join(internal->intr_tid, &status);
+       }
+       internal->intr_tid = 0;
+
+       if (internal->csc_epfd >= 0)
+               close(internal->csc_epfd);
+       internal->csc_epfd = -1;
+}
+
 static int
 update_datapath(struct ifcvf_internal *internal)
 {
@@ -592,10 +702,16 @@ update_datapath(struct ifcvf_internal *internal)
                if (ret)
                        goto err;
 
+               ret = setup_intr_relay(internal);
+               if (ret)
+                       goto err;
+
                rte_atomic32_set(&internal->running, 1);
        } else if (rte_atomic32_read(&internal->running) &&
                   (!rte_atomic32_read(&internal->started) ||
                    !rte_atomic32_read(&internal->dev_attached))) {
+               unset_intr_relay(internal);
+
                ret = unset_notify_relay(internal);
                if (ret)
                        goto err;
@@ -812,7 +928,7 @@ vring_relay(void *arg)
                if (nfds < 0) {
                        if (errno == EINTR)
                                continue;
-                       DRV_LOG(ERR, "epoll_wait return fail\n");
+                       DRV_LOG(ERR, "epoll_wait return fail.");
                        return NULL;
                }
 
@@ -888,6 +1004,9 @@ ifcvf_sw_fallback_switchover(struct ifcvf_internal *internal)
        /* stop the direct IO data path */
        unset_notify_relay(internal);
        vdpa_ifcvf_stop(internal);
+
+       unset_intr_relay(internal);
+
        vdpa_disable_vfio_intr(internal);
 
        ret = rte_vhost_host_notifier_ctrl(vid, RTE_VHOST_QUEUE_ALL, false);