virtio-net support

This adds virtio-net support.  This is based on the virtio-net driver 
that exists in kvm-userspace.  This also adds a new qemu_sendv_packet 
which virtio-net requires.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6073 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 329 insertions, 0 deletions

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
new file mode 100644
index 0000000000..c1269937a3
--- /dev/null
+++ b/hw/virtio-net.c
@@ -0,0 +1,329 @@
+/*
+ * Virtio Network Device
+ *
+ * Copyright IBM, Corp. 2007
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "virtio.h"
+#include "net.h"
+#include "qemu-timer.h"
+#include "virtio-net.h"
+
+typedef struct VirtIONet
+{
+    VirtIODevice vdev;
+    uint8_t mac[6];
+    VirtQueue *rx_vq;
+    VirtQueue *tx_vq;
+    VLANClientState *vc;
+    QEMUTimer *tx_timer;
+    int tx_timer_active;
+    int mergeable_rx_bufs;
+} VirtIONet;
+
+/* TODO
+ * - we could suppress RX interrupt if we were so inclined.
+ */
+
+static VirtIONet *to_virtio_net(VirtIODevice *vdev)
+{
+    return (VirtIONet *)vdev;
+}
+
+static void virtio_net_update_config(VirtIODevice *vdev, uint8_t *config)
+{
+    VirtIONet *n = to_virtio_net(vdev);
+    struct virtio_net_config netcfg;
+
+    memcpy(netcfg.mac, n->mac, 6);
+    memcpy(config, &netcfg, sizeof(netcfg));
+}
+
+static uint32_t virtio_net_get_features(VirtIODevice *vdev)
+{
+    uint32_t features = (1 << VIRTIO_NET_F_MAC);
+
+    return features;
+}
+
+static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
+{
+    VirtIONet *n = to_virtio_net(vdev);
+
+    n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));
+}
+
+/* RX */
+
+static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
+static int do_virtio_net_can_receive(VirtIONet *n, int bufsize)
+{
+    if (!virtio_queue_ready(n->rx_vq) ||
+        !(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
+        return 0;
+
+    if (virtio_queue_empty(n->rx_vq) ||
+        (n->mergeable_rx_bufs &&
+         !virtqueue_avail_bytes(n->rx_vq, bufsize, 0))) {
+        virtio_queue_set_notification(n->rx_vq, 1);
+        return 0;
+    }
+
+    virtio_queue_set_notification(n->rx_vq, 0);
+    return 1;
+}
+
+static int virtio_net_can_receive(void *opaque)
+{
+    VirtIONet *n = opaque;
+
+    return do_virtio_net_can_receive(n, VIRTIO_NET_MAX_BUFSIZE);
+}
+
+static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)
+{
+    int offset, i;
+
+    offset = i = 0;
+    while (offset < count && i < iovcnt) {
+        int len = MIN(iov[i].iov_len, count - offset);
+        memcpy(iov[i].iov_base, buf + offset, len);
+        offset += len;
+        i++;
+    }
+
+    return offset;
+}
+
+static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
+                          const void *buf, int size, int hdr_len)
+{
+    struct virtio_net_hdr *hdr = iov[0].iov_base;
+    int offset = 0;
+
+    hdr->flags = 0;
+    hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+    /* We only ever receive a struct virtio_net_hdr from the tapfd,
+     * but we may be passing along a larger header to the guest.
+     */
+    iov[0].iov_base += hdr_len;
+    iov[0].iov_len  -= hdr_len;
+
+    return offset;
+}
+
+static void virtio_net_receive(void *opaque, const uint8_t *buf, int size)
+{
+    VirtIONet *n = opaque;
+    struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;
+    int hdr_len, offset, i;
+
+    if (!do_virtio_net_can_receive(n, size))
+        return;
+
+    /* hdr_len refers to the header we supply to the guest */
+    hdr_len = n->mergeable_rx_bufs ?
+        sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct virtio_net_hdr);
+
+    offset = i = 0;
+
+    while (offset < size) {
+        VirtQueueElement elem;
+        int len, total;
+        struct iovec sg[VIRTQUEUE_MAX_SIZE];
+
+        len = total = 0;
+
+        if ((i != 0 && !n->mergeable_rx_bufs) ||
+            virtqueue_pop(n->rx_vq, &elem) == 0) {
+            if (i == 0)
+                return;
+            fprintf(stderr, "virtio-net truncating packet\n");
+            exit(1);
+        }
+
+        if (elem.in_num < 1) {
+            fprintf(stderr, "virtio-net receive queue contains no in buffers\n");
+            exit(1);
+        }
+
+        if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != hdr_len) {
+            fprintf(stderr, "virtio-net header not in first element\n");
+            exit(1);
+        }
+
+        memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);
+
+        if (i == 0) {
+            if (n->mergeable_rx_bufs)
+                mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;
+
+            offset += receive_header(n, sg, elem.in_num,
+                                     buf + offset, size - offset, hdr_len);
+            total += hdr_len;
+        }
+
+        /* copy in packet.  ugh */
+        len = iov_fill(sg, elem.in_num,
+                       buf + offset, size - offset);
+        total += len;
+
+        /* signal other side */
+        virtqueue_fill(n->rx_vq, &elem, total, i++);
+
+        offset += len;
+    }
+
+    if (mhdr)
+        mhdr->num_buffers = i;
+
+    virtqueue_flush(n->rx_vq, i);
+    virtio_notify(&n->vdev, n->rx_vq);
+}
+
+/* TX */
+static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
+{
+    VirtQueueElement elem;
+    int has_vnet_hdr = 0;
+
+    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
+        return;
+
+    while (virtqueue_pop(vq, &elem)) {
+        ssize_t len = 0;
+        unsigned int out_num = elem.out_num;
+        struct iovec *out_sg = &elem.out_sg[0];
+        unsigned hdr_len;
+
+        /* hdr_len refers to the header received from the guest */
+        hdr_len = n->mergeable_rx_bufs ?
+            sizeof(struct virtio_net_hdr_mrg_rxbuf) :
+            sizeof(struct virtio_net_hdr);
+
+        if (out_num < 1 || out_sg->iov_len != hdr_len) {
+            fprintf(stderr, "virtio-net header not in first element\n");
+            exit(1);
+        }
+
+        /* ignore the header if GSO is not supported */
+        if (!has_vnet_hdr) {
+            out_num--;
+            out_sg++;
+            len += hdr_len;
+        } else if (n->mergeable_rx_bufs) {
+            /* tapfd expects a struct virtio_net_hdr */
+            hdr_len -= sizeof(struct virtio_net_hdr);
+            out_sg->iov_len -= hdr_len;
+            len += hdr_len;
+        }
+
+        len += qemu_sendv_packet(n->vc, out_sg, out_num);
+
+        virtqueue_push(vq, &elem, len);
+        virtio_notify(&n->vdev, vq);
+    }
+}
+
+static void virtio_net_handle_tx(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIONet *n = to_virtio_net(vdev);
+
+    if (n->tx_timer_active) {
+        virtio_queue_set_notification(vq, 1);
+        qemu_del_timer(n->tx_timer);
+        n->tx_timer_active = 0;
+        virtio_net_flush_tx(n, vq);
+    } else {
+        qemu_mod_timer(n->tx_timer,
+                       qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
+        n->tx_timer_active = 1;
+        virtio_queue_set_notification(vq, 0);
+    }
+}
+
+static void virtio_net_tx_timer(void *opaque)
+{
+    VirtIONet *n = opaque;
+
+    n->tx_timer_active = 0;
+
+    /* Just in case the driver is not ready on more */
+    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
+        return;
+
+    virtio_queue_set_notification(n->tx_vq, 1);
+    virtio_net_flush_tx(n, n->tx_vq);
+}
+
+static void virtio_net_save(QEMUFile *f, void *opaque)
+{
+    VirtIONet *n = opaque;
+
+    virtio_save(&n->vdev, f);
+
+    qemu_put_buffer(f, n->mac, 6);
+    qemu_put_be32(f, n->tx_timer_active);
+}
+
+static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIONet *n = opaque;
+
+    if (version_id != 1)
+        return -EINVAL;
+
+    virtio_load(&n->vdev, f);
+
+    qemu_get_buffer(f, n->mac, 6);
+    n->tx_timer_active = qemu_get_be32(f);
+
+    if (n->tx_timer_active) {
+        qemu_mod_timer(n->tx_timer,
+                       qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
+    }
+
+    return 0;
+}
+
+PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
+{
+    VirtIONet *n;
+    static int virtio_net_id;
+
+    n = (VirtIONet *)virtio_init_pci(bus, "virtio-net", 6900, 0x1000,
+                                     0, VIRTIO_ID_NET,
+                                     0x02, 0x00, 0x00,
+                                     6, sizeof(VirtIONet));
+    if (!n)
+        return NULL;
+
+    n->vdev.get_config = virtio_net_update_config;
+    n->vdev.get_features = virtio_net_get_features;
+    n->vdev.set_features = virtio_net_set_features;
+    n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
+    n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);
+    memcpy(n->mac, nd->macaddr, 6);
+    n->vc = qemu_new_vlan_client(nd->vlan, virtio_net_receive,
+                                 virtio_net_can_receive, n);
+
+    n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);
+    n->tx_timer_active = 0;
+    n->mergeable_rx_bufs = 0;
+
+    register_savevm("virtio-net", virtio_net_id++, 1,
+                    virtio_net_save, virtio_net_load, n);
+
+    return (PCIDevice *)n;
+}