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.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include "net/net.h"

#include "net/tap.h"

#include "virtio-net.h"

#include "vhost_net.h"

#include "qemu/error-report.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;

    NetClientState *nc;

};

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_RING_F_EVENT_IDX))) {

        features &= ~(1 << VIRTIO_RING_F_EVENT_IDX);

    }

    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_RING_F_EVENT_IDX)) {

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

    }

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

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

    }

}

static int vhost_net_get_fd(NetClientState *backend)

{

    switch (backend->info->type) {

    case NET_CLIENT_OPTIONS_KIND_TAP:

        return tap_get_fd(backend);

    default:

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

        return -EBADFD;

    }

}

struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,

                                 bool force)

{

    int r;

    struct vhost_net *net = g_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->nc = backend;

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

        (1 << VHOST_NET_F_VIRTIO_NET_HDR);

    net->backend = r;

    net->dev.nvqs = 2;

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

    r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net", force);

    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:

    g_free(net);

    return NULL;

}

bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)

{

    return vhost_dev_query(&net->dev, dev);

}

static int vhost_net_start_one(struct vhost_net *net,

                               VirtIODevice *dev,

                               int vq_index)

{

    struct vhost_vring_file file = { };

    int r;

    if (net->dev.started) {

        return 0;

    }

    net->dev.nvqs = 2;

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

    net->dev.vq_index = vq_index;

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

    if (r < 0) {

        goto fail_notifiers;

    }

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

    if (r < 0) {

        goto fail_start;

    }

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

    vhost_dev_stop(&net->dev, dev);

fail_start:

    vhost_dev_disable_notifiers(&net->dev, dev);

fail_notifiers:

    return r;

}

static void vhost_net_stop_one(struct vhost_net *net,

                               VirtIODevice *dev)

{

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

    if (!net->dev.started) {

        return;

    }

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

    vhost_dev_stop(&net->dev, dev);

    vhost_dev_disable_notifiers(&net->dev, dev);

}

int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,

                    int total_queues)

{

    int r, i = 0;

    if (!dev->binding->set_guest_notifiers) {

        error_report("binding does not support guest notifiers");

        r = -ENOSYS;

        goto err;

    }

    for (i = 0; i < total_queues; i++) {

        r = vhost_net_start_one(tap_get_vhost_net(ncs[i].peer), dev, i * 2);

        if (r < 0) {

            goto err;

        }

    }

    r = dev->binding->set_guest_notifiers(dev->binding_opaque,

                                          total_queues * 2,

                                          true);

    if (r < 0) {

        error_report("Error binding guest notifier: %d", -r);

        goto err;

    }

    return 0;

err:

    while (--i >= 0) {

        vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);

    }

    return r;

}

void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,

                    int total_queues)

{

    int i, r;

    r = dev->binding->set_guest_notifiers(dev->binding_opaque,

                                          total_queues * 2,

                                          false);

    if (r < 0) {

        fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);

        fflush(stderr);

    }

    assert(r >= 0);

    for (i = 0; i < total_queues; i++) {

        vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);

    }

}

void vhost_net_cleanup(struct vhost_net *net)

{

    vhost_dev_cleanup(&net->dev);

    g_free(net);

}

bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)

{

    return vhost_virtqueue_pending(&net->dev, idx);

}

void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,

                              int idx, bool mask)

{

    vhost_virtqueue_mask(&net->dev, dev, idx, mask);

}

#else

struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,

                                 bool force)

{

    error_report("vhost-net support is not compiled in");

    return NULL;

}

bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)

{

    return false;

}

int vhost_net_start(VirtIODevice *dev,

                    NetClientState *ncs,

                    int total_queues)

{

    return -ENOSYS;

}

void vhost_net_stop(VirtIODevice *dev,

                    NetClientState *ncs,

                    int total_queues)

{

}

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)

{

}

bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)

{

    return -ENOSYS;

}

void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,

                              int idx, bool mask)

{

}

#endif