--- /dev/null
+/*
+ * (c) Copyright 2010 Stefan Hajnoczi <stefanha@gmail.com>
+ *
+ * based on the Etherboot virtio-net driver
+ *
+ * (c) Copyright 2008 Bull S.A.S.
+ *
+ * Author: Laurent Vivier <Laurent.Vivier@bull.net>
+ *
+ * some parts from Linux Virtio PCI driver
+ *
+ * Copyright IBM Corp. 2007
+ * Authors: Anthony Liguori <aliguori@us.ibm.com>
+ *
+ * some parts from Linux Virtio Ring
+ *
+ * Copyright Rusty Russell IBM Corporation 2007
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <errno.h>
+#include <stdlib.h>
+#include <ipxe/list.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/pci.h>
+#include <ipxe/if_ether.h>
+#include <ipxe/ethernet.h>
+#include <ipxe/virtio-ring.h>
+#include <ipxe/virtio-pci.h>
+#include "virtio-net.h"
+
+/*
+ * Virtio network device driver
+ *
+ * Specification:
+ * http://ozlabs.org/~rusty/virtio-spec/
+ *
+ * The virtio network device is supported by Linux virtualization software
+ * including QEMU/KVM and lguest. This driver supports the virtio over PCI
+ * transport; virtual machines have one virtio-net PCI adapter per NIC.
+ *
+ * Virtio-net is different from hardware NICs because virtio devices
+ * communicate with the hypervisor via virtqueues, not traditional descriptor
+ * rings. Virtqueues are unordered queues, they support add_buf() and
+ * get_buf() operations. To transmit a packet, the driver has to add the
+ * packet buffer onto the virtqueue. To receive a packet, the driver must
+ * first add an empty buffer to the virtqueue and then get the filled packet
+ * buffer on completion.
+ *
+ * Virtqueues are an abstraction that is commonly implemented using the vring
+ * descriptor ring layout. The vring is the actual shared memory structure
+ * that allows the virtual machine to communicate buffers with the hypervisor.
+ * Because the vring layout is optimized for flexibility and performance rather
+ * than space, it is heavy-weight and allocated like traditional descriptor
+ * rings in the open() function of the driver and not in probe().
+ *
+ * There is no true interrupt enable/disable. Virtqueues have callback
+ * enable/disable flags but these are only hints. The hypervisor may still
+ * raise an interrupt. Nevertheless, this driver disables callbacks in the
+ * hopes of avoiding interrupts.
+ */
+
+/* Driver types are declared here so virtio-net.h can be easily synced with its
+ * Linux source.
+ */
+
+/* Virtqueue indices */
+enum {
+ RX_INDEX = 0,
+ TX_INDEX,
+ QUEUE_NB
+};
+
+enum {
+ /** Max number of pending rx packets */
+ NUM_RX_BUF = 8,
+
+ /** Max Ethernet frame length, including FCS and VLAN tag */
+ RX_BUF_SIZE = 1522,
+};
+
+struct virtnet_nic {
+ /** Base pio register address */
+ unsigned long ioaddr;
+
+ /** RX/TX virtqueues */
+ struct vring_virtqueue *virtqueue;
+
+ /** RX packets handed to the NIC waiting to be filled in */
+ struct list_head rx_iobufs;
+
+ /** Pending rx packet count */
+ unsigned int rx_num_iobufs;
+
+ /** Virtio net packet header, we only need one */
+ struct virtio_net_hdr empty_header;
+};
+
+/** Add an iobuf to a virtqueue
+ *
+ * @v netdev Network device
+ * @v vq_idx Virtqueue index (RX_INDEX or TX_INDEX)
+ * @v iobuf I/O buffer
+ *
+ * The virtqueue is kicked after the iobuf has been added.
+ */
+static void virtnet_enqueue_iob ( struct net_device *netdev,
+ int vq_idx, struct io_buffer *iobuf ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ struct vring_virtqueue *vq = &virtnet->virtqueue[vq_idx];
+ unsigned int out = ( vq_idx == TX_INDEX ) ? 2 : 0;
+ unsigned int in = ( vq_idx == TX_INDEX ) ? 0 : 2;
+ struct vring_list list[] = {
+ {
+ /* Share a single zeroed virtio net header between all
+ * rx and tx packets. This works because this driver
+ * does not use any advanced features so none of the
+ * header fields get used.
+ */
+ .addr = ( char* ) &virtnet->empty_header,
+ .length = sizeof ( virtnet->empty_header ),
+ },
+ {
+ .addr = ( char* ) iobuf->data,
+ .length = iob_len ( iobuf ),
+ },
+ };
+
+ DBGC ( virtnet, "VIRTIO-NET %p enqueuing iobuf %p on vq %d\n",
+ virtnet, iobuf, vq_idx );
+
+ vring_add_buf ( vq, list, out, in, iobuf, 0 );
+ vring_kick ( virtnet->ioaddr, vq, 1 );
+}
+
+/** Try to keep rx virtqueue filled with iobufs
+ *
+ * @v netdev Network device
+ */
+static void virtnet_refill_rx_virtqueue ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+
+ while ( virtnet->rx_num_iobufs < NUM_RX_BUF ) {
+ struct io_buffer *iobuf;
+
+ /* Try to allocate a buffer, stop for now if out of memory */
+ iobuf = alloc_iob ( RX_BUF_SIZE );
+ if ( ! iobuf )
+ break;
+
+ /* Keep track of iobuf so close() can free it */
+ list_add ( &iobuf->list, &virtnet->rx_iobufs );
+
+ /* Mark packet length until we know the actual size */
+ iob_put ( iobuf, RX_BUF_SIZE );
+
+ virtnet_enqueue_iob ( netdev, RX_INDEX, iobuf );
+ virtnet->rx_num_iobufs++;
+ }
+}
+
+/** Open network device
+ *
+ * @v netdev Network device
+ * @ret rc Return status code
+ */
+static int virtnet_open ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ unsigned long ioaddr = virtnet->ioaddr;
+ u32 features;
+ int i;
+
+ /* Reset for sanity */
+ vp_reset ( ioaddr );
+
+ /* Allocate virtqueues */
+ virtnet->virtqueue = zalloc ( QUEUE_NB *
+ sizeof ( *virtnet->virtqueue ) );
+ if ( ! virtnet->virtqueue )
+ return -ENOMEM;
+
+ /* Initialize rx/tx virtqueues */
+ for ( i = 0; i < QUEUE_NB; i++ ) {
+ if ( vp_find_vq ( ioaddr, i, &virtnet->virtqueue[i] ) == -1 ) {
+ DBGC ( virtnet, "VIRTIO-NET %p cannot register queue %d\n",
+ virtnet, i );
+ free ( virtnet->virtqueue );
+ virtnet->virtqueue = NULL;
+ return -ENOENT;
+ }
+ }
+
+ /* Initialize rx packets */
+ INIT_LIST_HEAD ( &virtnet->rx_iobufs );
+ virtnet->rx_num_iobufs = 0;
+ virtnet_refill_rx_virtqueue ( netdev );
+
+ /* Disable interrupts before starting */
+ netdev_irq ( netdev, 0 );
+
+ /* Driver is ready */
+ features = vp_get_features ( ioaddr );
+ vp_set_features ( ioaddr, features & ( 1 << VIRTIO_NET_F_MAC ) );
+ vp_set_status ( ioaddr, VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK );
+ return 0;
+}
+
+/** Close network device
+ *
+ * @v netdev Network device
+ */
+static void virtnet_close ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ struct io_buffer *iobuf;
+ struct io_buffer *next_iobuf;
+
+ vp_reset ( virtnet->ioaddr );
+
+ /* Virtqueues can be freed now that NIC is reset */
+ free ( virtnet->virtqueue );
+ virtnet->virtqueue = NULL;
+
+ /* Free rx iobufs */
+ list_for_each_entry_safe ( iobuf, next_iobuf, &virtnet->rx_iobufs, list ) {
+ free_iob ( iobuf );
+ }
+ INIT_LIST_HEAD ( &virtnet->rx_iobufs );
+ virtnet->rx_num_iobufs = 0;
+}
+
+/** Transmit packet
+ *
+ * @v netdev Network device
+ * @v iobuf I/O buffer
+ * @ret rc Return status code
+ */
+static int virtnet_transmit ( struct net_device *netdev,
+ struct io_buffer *iobuf ) {
+ virtnet_enqueue_iob ( netdev, TX_INDEX, iobuf );
+ return 0;
+}
+
+/** Complete packet transmission
+ *
+ * @v netdev Network device
+ */
+static void virtnet_process_tx_packets ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ struct vring_virtqueue *tx_vq = &virtnet->virtqueue[TX_INDEX];
+
+ while ( vring_more_used ( tx_vq ) ) {
+ struct io_buffer *iobuf = vring_get_buf ( tx_vq, NULL );
+
+ DBGC ( virtnet, "VIRTIO-NET %p tx complete iobuf %p\n",
+ virtnet, iobuf );
+
+ netdev_tx_complete ( netdev, iobuf );
+ }
+}
+
+/** Complete packet reception
+ *
+ * @v netdev Network device
+ */
+static void virtnet_process_rx_packets ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ struct vring_virtqueue *rx_vq = &virtnet->virtqueue[RX_INDEX];
+
+ while ( vring_more_used ( rx_vq ) ) {
+ unsigned int len;
+ struct io_buffer *iobuf = vring_get_buf ( rx_vq, &len );
+
+ /* Release ownership of iobuf */
+ list_del ( &iobuf->list );
+ virtnet->rx_num_iobufs--;
+
+ /* Update iobuf length */
+ iob_unput ( iobuf, RX_BUF_SIZE );
+ iob_put ( iobuf, len - sizeof ( struct virtio_net_hdr ) );
+
+ DBGC ( virtnet, "VIRTIO-NET %p rx complete iobuf %p len %zd\n",
+ virtnet, iobuf, iob_len ( iobuf ) );
+
+ /* Pass completed packet to the network stack */
+ netdev_rx ( netdev, iobuf );
+ }
+
+ virtnet_refill_rx_virtqueue ( netdev );
+}
+
+/** Poll for completed and received packets
+ *
+ * @v netdev Network device
+ */
+static void virtnet_poll ( struct net_device *netdev ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+
+ /* Acknowledge interrupt. This is necessary for UNDI operation and
+ * interrupts that are raised despite VRING_AVAIL_F_NO_INTERRUPT being
+ * set (that flag is just a hint and the hypervisor not not have to
+ * honor it).
+ */
+ vp_get_isr ( virtnet->ioaddr );
+
+ virtnet_process_tx_packets ( netdev );
+ virtnet_process_rx_packets ( netdev );
+}
+
+/** Enable or disable interrupts
+ *
+ * @v netdev Network device
+ * @v enable Interrupts should be enabled
+ */
+static void virtnet_irq ( struct net_device *netdev, int enable ) {
+ struct virtnet_nic *virtnet = netdev->priv;
+ int i;
+
+ for ( i = 0; i < QUEUE_NB; i++ ) {
+ if ( enable )
+ vring_enable_cb ( &virtnet->virtqueue[i] );
+ else
+ vring_disable_cb ( &virtnet->virtqueue[i] );
+ }
+}
+
+/** virtio-net device operations */
+static struct net_device_operations virtnet_operations = {
+ .open = virtnet_open,
+ .close = virtnet_close,
+ .transmit = virtnet_transmit,
+ .poll = virtnet_poll,
+ .irq = virtnet_irq,
+};
+
+/**
+ * Probe PCI device
+ *
+ * @v pci PCI device
+ * @v id PCI ID
+ * @ret rc Return status code
+ */
+static int virtnet_probe ( struct pci_device *pci ) {
+ unsigned long ioaddr = pci->ioaddr;
+ struct net_device *netdev;
+ struct virtnet_nic *virtnet;
+ u32 features;
+ int rc;
+
+ /* Allocate and hook up net device */
+ netdev = alloc_etherdev ( sizeof ( *virtnet ) );
+ if ( ! netdev )
+ return -ENOMEM;
+ netdev_init ( netdev, &virtnet_operations );
+ virtnet = netdev->priv;
+ virtnet->ioaddr = ioaddr;
+ pci_set_drvdata ( pci, netdev );
+ netdev->dev = &pci->dev;
+
+ DBGC ( virtnet, "VIRTIO-NET %p busaddr=%s ioaddr=%#lx irq=%d\n",
+ virtnet, pci->dev.name, ioaddr, pci->irq );
+
+ /* Enable PCI bus master and reset NIC */
+ adjust_pci_device ( pci );
+ vp_reset ( ioaddr );
+
+ /* Load MAC address */
+ features = vp_get_features ( ioaddr );
+ if ( features & ( 1 << VIRTIO_NET_F_MAC ) ) {
+ vp_get ( ioaddr, offsetof ( struct virtio_net_config, mac ),
+ netdev->hw_addr, ETH_ALEN );
+ DBGC ( virtnet, "VIRTIO-NET %p mac=%s\n", virtnet,
+ eth_ntoa ( netdev->hw_addr ) );
+ }
+
+ /* Register network device */
+ if ( ( rc = register_netdev ( netdev ) ) != 0 )
+ goto err_register_netdev;
+
+ /* Mark link as up, control virtqueue is not used */
+ netdev_link_up ( netdev );
+
+ return 0;
+
+ unregister_netdev ( netdev );
+ err_register_netdev:
+ vp_reset ( ioaddr );
+ netdev_nullify ( netdev );
+ netdev_put ( netdev );
+ return rc;
+}
+
+/**
+ * Remove device
+ *
+ * @v pci PCI device
+ */
+static void virtnet_remove ( struct pci_device *pci ) {
+ struct net_device *netdev = pci_get_drvdata ( pci );
+
+ unregister_netdev ( netdev );
+ netdev_nullify ( netdev );
+ netdev_put ( netdev );
+}
+
+static struct pci_device_id virtnet_nics[] = {
+PCI_ROM(0x1af4, 0x1000, "virtio-net", "Virtio Network Interface", 0),
+};
+
+struct pci_driver virtnet_driver __pci_driver = {
+ .ids = virtnet_nics,
+ .id_count = ( sizeof ( virtnet_nics ) / sizeof ( virtnet_nics[0] ) ),
+ .probe = virtnet_probe,
+ .remove = virtnet_remove,
+};
Code Review / kvmfornfv.git / blobdiff