* Virtio supports Link State interrupt.
+* Virtio supports Rx interrupt (so far, only support 1:1 mapping for queue/interrupt).
+
* Virtio supports software vlan stripping and inserting.
* Virtio supports using port IO to get PCI resource when uio/igb_uio module is not available.
``testpmd``::
testpmd -c 0x7 -n 4 -- -i --txqflags=0xF01 --rxq=1 --txq=1 --nb-cores=1
+
+
+Interrupt mode
+--------------
+
+.. _virtio_interrupt_mode:
+
+There are three kinds of interrupts from a virtio device over PCI bus: config
+interrupt, Rx interrupts, and Tx interrupts. Config interrupt is used for
+notification of device configuration changes, especially link status (lsc).
+Interrupt mode is translated into Rx interrupts in the context of DPDK.
+
+Prerequisites for Rx interrupts
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To support Rx interrupts,
+#. Check if guest kernel supports VFIO-NOIOMMU:
+
+ Linux started to support VFIO-NOIOMMU since 4.8.0. Make sure the guest
+ kernel is compiled with:
+
+ .. code-block:: console
+
+ CONFIG_VFIO_NOIOMMU=y
+
+#. Properly set msix vectors when starting VM:
+
+ Enable multi-queue when starting VM, and specify msix vectors in qemu
+ cmdline. (N+1) is the minimum, and (2N+2) is mostly recommended.
+
+ .. code-block:: console
+
+ $(QEMU) ... -device virtio-net-pci,mq=on,vectors=2N+2 ...
+
+#. In VM, insert vfio module in NOIOMMU mode:
+
+ .. code-block:: console
+
+ modprobe vfio enable_unsafe_noiommu_mode=1
+ modprobe vfio-pci
+
+#. In VM, bind the virtio device with vfio-pci:
+
+ .. code-block:: console
+
+ python tools/dpdk-devbind.py -b vfio-pci 00:03.0
+
+Example
+~~~~~~~
+
+Here we use l3fwd-power as an example to show how to get started.
+
+ Example:
+
+ .. code-block:: console
+
+ $ l3fwd-power -c 0x3 -- -p 1 -P --config="(0,0,1)" \
+ --no-numa --parse-ptype
it might enter into kernel space to wake up those kthreads if
necessary).
+* **Added virtio Rx interrupt suppprt.**
+
+ This feature enables Rx interrupt mode for virtio pci net devices as
+ binded to VFIO (noiommu mode) and drived by virtio PMD.
+
+ With this feature, virtio PMD can switch between polling mode and
+ interrupt mode, to achieve best performance, and at the same time save
+ power. It can work on both legacy and modern virtio devices. At this mode,
+ each rxq is mapped with an exluded MSIx interrupt.
+
+ See the :ref:`Virtio Interrupt Mode <virtio_interrupt_mode>` documentation
+ for more information.
+
Resolved Issues
---------------
eth_dev->rx_pkt_burst = &virtio_recv_pkts;
}
+/* Only support 1:1 queue/interrupt mapping so far.
+ * TODO: support n:1 queue/interrupt mapping when there are limited number of
+ * interrupt vectors (<N+1).
+ */
+static int
+virtio_queues_bind_intr(struct rte_eth_dev *dev)
+{
+ uint32_t i;
+ struct virtio_hw *hw = dev->data->dev_private;
+
+ PMD_INIT_LOG(INFO, "queue/interrupt binding\n");
+ for (i = 0; i < dev->data->nb_rx_queues; ++i) {
+ dev->intr_handle->intr_vec[i] = i + 1;
+ if (VTPCI_OPS(hw)->set_queue_irq(hw, hw->vqs[i * 2], i + 1) ==
+ VIRTIO_MSI_NO_VECTOR) {
+ PMD_DRV_LOG(ERR, "failed to set queue vector");
+ return -EBUSY;
+ }
+ }
+
+ return 0;
+}
+
+static int
+virtio_configure_intr(struct rte_eth_dev *dev)
+{
+ struct virtio_hw *hw = dev->data->dev_private;
+
+ if (!rte_intr_cap_multiple(dev->intr_handle)) {
+ PMD_INIT_LOG(ERR, "Multiple intr vector not supported");
+ return -ENOTSUP;
+ }
+
+ if (rte_intr_efd_enable(dev->intr_handle, dev->data->nb_rx_queues)) {
+ PMD_INIT_LOG(ERR, "Fail to create eventfd");
+ return -1;
+ }
+
+ if (!dev->intr_handle->intr_vec) {
+ dev->intr_handle->intr_vec =
+ rte_zmalloc("intr_vec",
+ hw->max_queue_pairs * sizeof(int), 0);
+ if (!dev->intr_handle->intr_vec) {
+ PMD_INIT_LOG(ERR, "Failed to allocate %u rxq vectors",
+ hw->max_queue_pairs);
+ return -ENOMEM;
+ }
+ }
+
+ /* Re-register callback to update max_intr */
+ rte_intr_callback_unregister(dev->intr_handle,
+ virtio_interrupt_handler,
+ dev);
+ rte_intr_callback_register(dev->intr_handle,
+ virtio_interrupt_handler,
+ dev);
+
+ /* DO NOT try to remove this! This function will enable msix, or QEMU
+ * will encounter SIGSEGV when DRIVER_OK is sent.
+ * And for legacy devices, this should be done before queue/vec binding
+ * to change the config size from 20 to 24, or VIRTIO_MSI_QUEUE_VECTOR
+ * (22) will be ignored.
+ */
+ if (rte_intr_enable(dev->intr_handle) < 0) {
+ PMD_DRV_LOG(ERR, "interrupt enable failed");
+ return -1;
+ }
+
+ if (virtio_queues_bind_intr(dev) < 0) {
+ PMD_INIT_LOG(ERR, "Failed to bind queue/interrupt");
+ return -1;
+ }
+
+ return 0;
+}
+
/* reset device and renegotiate features if needed */
static int
virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features)
ret = virtio_alloc_queues(eth_dev);
if (ret < 0)
return ret;
+
+ if (eth_dev->data->dev_conf.intr_conf.rxq) {
+ if (virtio_configure_intr(eth_dev) < 0) {
+ PMD_INIT_LOG(ERR, "failed to configure interrupt");
+ return -1;
+ }
+ }
+
vtpci_reinit_complete(hw);
if (pci_dev)
git.droids-corp.org / dpdk.git / commitdiff