[Qemu-devel] Re: [PATCH 2/3] virtio network device

[Dor Laor <dor.laor@gmail.com>]

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Anthony Liguori wrote:

Index: qemu/hw/virtio-net.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ qemu/hw/virtio-net.c	2007-12-04 14:17:37.000000000 -0600

+
+static void virtio_net_receive(void *opaque, const uint8_t *buf, int size)
+{
+    VirtIONet *n = opaque;
+    VirtQueueElement elem;
+    struct virtio_net_hdr *hdr;
+    int offset, i;
+
+    /* FIXME: the drivers really need to set their status better */
+    if (n->rx_vq->vring.avail == NULL) {
+	n->can_receive = 0;
+	return;
+    }
+
+    if (virtqueue_pop(n->rx_vq, &elem) == 0) {
+	/* wait until the guest adds some rx bufs */
+	n->can_receive = 0;
+	return;
+    }
+
+    hdr = (void *)elem.in_sg[0].iov_base;
+    hdr->flags = 0;
+    hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+    /* copy in packet.  ugh */
+    offset = 0;
+    i = 1;
+    while (offset < size && i < elem.in_num) {
+	int len = MIN(elem.in_sg[i].iov_len, size - offset);
+	memcpy(elem.in_sg[i].iov_base, buf + offset, len);



Actually according to qemu's standard, one should use cpu_physical_memory_write/
cpu_physical_memory_read functions.
This is true also for reading the ring values.




+	offset += len;
+	i++;
+    }
+
+    /* signal other side */
+    virtqueue_push(n->rx_vq, &elem, sizeof(*hdr) + offset);
+    virtio_notify(&n->vdev, n->rx_vq);
+}
+
+/* TX */
+static void virtio_net_handle_tx(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIONet *n = to_virtio_net(vdev);
+    VirtQueueElement elem;
+
+    while (virtqueue_pop(vq, &elem)) {
+	int i;
+	size_t len = 0;
+
+	/* ignore the header for now */
+	for (i = 1; i < elem.out_num; i++) {
+	    qemu_send_packet(n->vc, elem.out_sg[i].iov_base,
+			     elem.out_sg[i].iov_len);
+	    len += elem.out_sg[i].iov_len;
+	}
+
+	virtqueue_push(vq, &elem, sizeof(struct virtio_net_hdr) + len);
+	virtio_notify(&n->vdev, vq);
+    }


The virtio_notify should be left out of the while loop to minimize 
irq injection.


+}
+
+void *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
+{
+    VirtIONet *n;
+
+    n = (VirtIONet *)virtio_init_pci(bus, "virtio-net", 6900, 0x1000,
+				     0, VIRTIO_ID_NET,
+				     0x02, 0x00, 0x00,
+				     6, sizeof(VirtIONet));
+
+    n->vdev.update_config = virtio_net_update_config;
+    n->vdev.get_features = virtio_net_get_features;
+    n->rx_vq = virtio_add_queue(&n->vdev, 512, virtio_net_handle_rx);
+    n->tx_vq = virtio_add_queue(&n->vdev, 128, virtio_net_handle_tx);
+    n->can_receive = 0;
+    memcpy(n->mac, nd->macaddr, 6);
+    n->vc = qemu_new_vlan_client(nd->vlan, virtio_net_receive,
+				 virtio_net_can_receive, n);
+
+    return &n->vdev;
+}
Index: qemu/hw/pc.h
===================================================================
--- qemu.orig/hw/pc.h	2007-12-04 14:15:20.000000000 -0600
+++ qemu/hw/pc.h	2007-12-04 14:43:57.000000000 -0600
@@ -142,4 +142,9 @@
 
 void isa_ne2000_init(int base, qemu_irq irq, NICInfo *nd);
 
+/* virtio-net.c */
+
+void *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn);
+
+
 #endif


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