Archipelago » qemu

/*

 * vhost-net support

 *

 * Copyright Red Hat, Inc. 2010

 *

 * Authors:

 *  Michael S. Tsirkin <mst@redhat.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 */

#include "net.h"

#include "net/tap.h"

#include "virtio-net.h"

#include "vhost_net.h"

#include "config.h"

#ifdef CONFIG_VHOST_NET

#include <linux/vhost.h>

#include <sys/socket.h>

#include <linux/kvm.h>

#include <fcntl.h>

#include <sys/ioctl.h>

#include <linux/virtio_ring.h>

#include <netpacket/packet.h>

#include <net/ethernet.h>

#include <net/if.h>

#include <netinet/in.h>

#include <stdio.h>

#include "vhost.h"

struct vhost_net {

    struct vhost_dev dev;

    struct vhost_virtqueue vqs[2];

    int backend;

    VLANClientState *vc;

};

unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)

{

    /* Clear features not supported by host kernel. */

    if (!(net->dev.features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY))) {

        features &= ~(1 << VIRTIO_F_NOTIFY_ON_EMPTY);

    }

    if (!(net->dev.features & (1 << VIRTIO_RING_F_INDIRECT_DESC))) {

        features &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);

    }

    if (!(net->dev.features & (1 << VIRTIO_NET_F_MRG_RXBUF))) {

        features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);

    }

    return features;

}

void vhost_net_ack_features(struct vhost_net *net, unsigned features)

{

    net->dev.acked_features = net->dev.backend_features;

    if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {

        net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);

    }

    if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {

        net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);

    }

    if (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {

        net->dev.acked_features |= (1 << VIRTIO_NET_F_MRG_RXBUF);

    }

}

static int vhost_net_get_fd(VLANClientState *backend)

{

    switch (backend->info->type) {

    case NET_CLIENT_TYPE_TAP:

        return tap_get_fd(backend);

    default:

        fprintf(stderr, "vhost-net requires tap backend\n");

        return -EBADFD;

    }

}

struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)

{

    int r;

    struct vhost_net *net = qemu_malloc(sizeof *net);

    if (!backend) {

        fprintf(stderr, "vhost-net requires backend to be setup\n");

        goto fail;

    }

    r = vhost_net_get_fd(backend);

    if (r < 0) {

        goto fail;

    }

    net->vc = backend;

    net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :

        (1 << VHOST_NET_F_VIRTIO_NET_HDR);

    net->backend = r;

    r = vhost_dev_init(&net->dev, devfd);

    if (r < 0) {

        goto fail;

    }

    if (!tap_has_vnet_hdr_len(backend,

                              sizeof(struct virtio_net_hdr_mrg_rxbuf))) {

        net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);

    }

    if (~net->dev.features & net->dev.backend_features) {

        fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",

                (uint64_t)(~net->dev.features & net->dev.backend_features));

        vhost_dev_cleanup(&net->dev);

        goto fail;

    }

    /* Set sane init value. Override when guest acks. */

    vhost_net_ack_features(net, 0);

    return net;

fail:

    qemu_free(net);

    return NULL;

}

int vhost_net_start(struct vhost_net *net,

                    VirtIODevice *dev)

{

    struct vhost_vring_file file = { };

    int r;

    if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {

        tap_set_vnet_hdr_len(net->vc,

                             sizeof(struct virtio_net_hdr_mrg_rxbuf));

    }

    net->dev.nvqs = 2;

    net->dev.vqs = net->vqs;

    r = vhost_dev_start(&net->dev, dev);

    if (r < 0) {

        return r;

    }

    net->vc->info->poll(net->vc, false);

    qemu_set_fd_handler(net->backend, NULL, NULL, NULL);

    file.fd = net->backend;

    for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {

        r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);

        if (r < 0) {

            r = -errno;

            goto fail;

        }

    }

    return 0;

fail:

    file.fd = -1;

    while (file.index-- > 0) {

        int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);

        assert(r >= 0);

    }

    net->vc->info->poll(net->vc, true);

    vhost_dev_stop(&net->dev, dev);

    if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {

        tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));

    }

    return r;

}

void vhost_net_stop(struct vhost_net *net,

                    VirtIODevice *dev)

{

    struct vhost_vring_file file = { .fd = -1 };

    for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {

        int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);

        assert(r >= 0);

    }

    net->vc->info->poll(net->vc, true);

    vhost_dev_stop(&net->dev, dev);

    if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {

        tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));

    }

}

void vhost_net_cleanup(struct vhost_net *net)

{

    vhost_dev_cleanup(&net->dev);

    if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {

        tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));

    }

    qemu_free(net);

}

#else

struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)

{

        return NULL;

}

int vhost_net_start(struct vhost_net *net,

                    VirtIODevice *dev)

{

        return -ENOSYS;

}

void vhost_net_stop(struct vhost_net *net,

                    VirtIODevice *dev)

{

}

void vhost_net_cleanup(struct vhost_net *net)

{

}

unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)

{

        return features;

}

void vhost_net_ack_features(struct vhost_net *net, unsigned features)

{

}

#endif