Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 438 insertions, 0 deletions

diff --git a/net/vhost-user.c b/net/vhost-user.c
new file mode 100644
index 000000000..b1a0247b5
--- /dev/null
+++ b/net/vhost-user.c
@@ -0,0 +1,438 @@
+/*
+ * vhost-user.c
+ *
+ * Copyright (c) 2013 Virtual Open Systems Sarl.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "clients.h"
+#include "net/vhost_net.h"
+#include "net/vhost-user.h"
+#include "hw/virtio/vhost-user.h"
+#include "chardev/char-fe.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-net.h"
+#include "qemu/config-file.h"
+#include "qemu/error-report.h"
+#include "qemu/option.h"
+#include "trace.h"
+
+typedef struct NetVhostUserState {
+    NetClientState nc;
+    CharBackend chr; /* only queue index 0 */
+    VhostUserState *vhost_user;
+    VHostNetState *vhost_net;
+    guint watch;
+    uint64_t acked_features;
+    bool started;
+} NetVhostUserState;
+
+VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
+{
+    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+    return s->vhost_net;
+}
+
+uint64_t vhost_user_get_acked_features(NetClientState *nc)
+{
+    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+    return s->acked_features;
+}
+
+static void vhost_user_stop(int queues, NetClientState *ncs[])
+{
+    NetVhostUserState *s;
+    int i;
+
+    for (i = 0; i < queues; i++) {
+        assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+
+        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
+
+        if (s->vhost_net) {
+            /* save acked features */
+            uint64_t features = vhost_net_get_acked_features(s->vhost_net);
+            if (features) {
+                s->acked_features = features;
+            }
+            vhost_net_cleanup(s->vhost_net);
+        }
+    }
+}
+
+static int vhost_user_start(int queues, NetClientState *ncs[],
+                            VhostUserState *be)
+{
+    VhostNetOptions options;
+    struct vhost_net *net = NULL;
+    NetVhostUserState *s;
+    int max_queues;
+    int i;
+
+    options.backend_type = VHOST_BACKEND_TYPE_USER;
+
+    for (i = 0; i < queues; i++) {
+        assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+
+        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
+
+        options.net_backend = ncs[i];
+        options.opaque      = be;
+        options.busyloop_timeout = 0;
+        options.nvqs = 2;
+        net = vhost_net_init(&options);
+        if (!net) {
+            error_report("failed to init vhost_net for queue %d", i);
+            goto err;
+        }
+
+        if (i == 0) {
+            max_queues = vhost_net_get_max_queues(net);
+            if (queues > max_queues) {
+                error_report("you are asking more queues than supported: %d",
+                             max_queues);
+                goto err;
+            }
+        }
+
+        if (s->vhost_net) {
+            vhost_net_cleanup(s->vhost_net);
+            g_free(s->vhost_net);
+        }
+        s->vhost_net = net;
+    }
+
+    return 0;
+
+err:
+    if (net) {
+        vhost_net_cleanup(net);
+        g_free(net);
+    }
+    vhost_user_stop(i, ncs);
+    return -1;
+}
+
+static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
+                                  size_t size)
+{
+    /* In case of RARP (message size is 60) notify backup to send a fake RARP.
+       This fake RARP will be sent by backend only for guest
+       without GUEST_ANNOUNCE capability.
+     */
+    if (size == 60) {
+        NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
+        int r;
+        static int display_rarp_failure = 1;
+        char mac_addr[6];
+
+        /* extract guest mac address from the RARP message */
+        memcpy(mac_addr, &buf[6], 6);
+
+        r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
+
+        if ((r != 0) && (display_rarp_failure)) {
+            fprintf(stderr,
+                    "Vhost user backend fails to broadcast fake RARP\n");
+            fflush(stderr);
+            display_rarp_failure = 0;
+        }
+    }
+
+    return size;
+}
+
+static void net_vhost_user_cleanup(NetClientState *nc)
+{
+    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
+
+    if (s->vhost_net) {
+        vhost_net_cleanup(s->vhost_net);
+        g_free(s->vhost_net);
+        s->vhost_net = NULL;
+    }
+    if (nc->queue_index == 0) {
+        if (s->watch) {
+            g_source_remove(s->watch);
+            s->watch = 0;
+        }
+        qemu_chr_fe_deinit(&s->chr, true);
+        if (s->vhost_user) {
+            vhost_user_cleanup(s->vhost_user);
+            g_free(s->vhost_user);
+            s->vhost_user = NULL;
+        }
+    }
+
+    qemu_purge_queued_packets(nc);
+}
+
+static int vhost_user_set_vnet_endianness(NetClientState *nc,
+                                          bool enable)
+{
+    /* Nothing to do.  If the server supports
+     * VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, it will get the
+     * vnet header endianness from there.  If it doesn't, negotiation
+     * fails.
+     */
+    return 0;
+}
+
+static bool vhost_user_has_vnet_hdr(NetClientState *nc)
+{
+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+
+    return true;
+}
+
+static bool vhost_user_has_ufo(NetClientState *nc)
+{
+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
+
+    return true;
+}
+
+static bool vhost_user_check_peer_type(NetClientState *nc, ObjectClass *oc,
+                                       Error **errp)
+{
+    const char *driver = object_class_get_name(oc);
+
+    if (!g_str_has_prefix(driver, "virtio-net-")) {
+        error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
+        return false;
+    }
+
+    return true;
+}
+
+static NetClientInfo net_vhost_user_info = {
+        .type = NET_CLIENT_DRIVER_VHOST_USER,
+        .size = sizeof(NetVhostUserState),
+        .receive = vhost_user_receive,
+        .cleanup = net_vhost_user_cleanup,
+        .has_vnet_hdr = vhost_user_has_vnet_hdr,
+        .has_ufo = vhost_user_has_ufo,
+        .set_vnet_be = vhost_user_set_vnet_endianness,
+        .set_vnet_le = vhost_user_set_vnet_endianness,
+        .check_peer_type = vhost_user_check_peer_type,
+};
+
+static gboolean net_vhost_user_watch(void *do_not_use, GIOCondition cond,
+                                     void *opaque)
+{
+    NetVhostUserState *s = opaque;
+
+    qemu_chr_fe_disconnect(&s->chr);
+
+    return TRUE;
+}
+
+static void net_vhost_user_event(void *opaque, QEMUChrEvent event);
+
+static void chr_closed_bh(void *opaque)
+{
+    const char *name = opaque;
+    NetClientState *ncs[MAX_QUEUE_NUM];
+    NetVhostUserState *s;
+    Error *err = NULL;
+    int queues, i;
+
+    queues = qemu_find_net_clients_except(name, ncs,
+                                          NET_CLIENT_DRIVER_NIC,
+                                          MAX_QUEUE_NUM);
+    assert(queues < MAX_QUEUE_NUM);
+
+    s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
+
+    for (i = queues -1; i >= 0; i--) {
+        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
+
+        if (s->vhost_net) {
+            s->acked_features = vhost_net_get_acked_features(s->vhost_net);
+        }
+    }
+
+    qmp_set_link(name, false, &err);
+
+    qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
+                             NULL, opaque, NULL, true);
+
+    if (err) {
+        error_report_err(err);
+    }
+}
+
+static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
+{
+    const char *name = opaque;
+    NetClientState *ncs[MAX_QUEUE_NUM];
+    NetVhostUserState *s;
+    Chardev *chr;
+    Error *err = NULL;
+    int queues;
+
+    queues = qemu_find_net_clients_except(name, ncs,
+                                          NET_CLIENT_DRIVER_NIC,
+                                          MAX_QUEUE_NUM);
+    assert(queues < MAX_QUEUE_NUM);
+
+    s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
+    chr = qemu_chr_fe_get_driver(&s->chr);
+    trace_vhost_user_event(chr->label, event);
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
+            qemu_chr_fe_disconnect(&s->chr);
+            return;
+        }
+        s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
+                                         net_vhost_user_watch, s);
+        qmp_set_link(name, true, &err);
+        s->started = true;
+        break;
+    case CHR_EVENT_CLOSED:
+        /* a close event may happen during a read/write, but vhost
+         * code assumes the vhost_dev remains setup, so delay the
+         * stop & clear to idle.
+         * FIXME: better handle failure in vhost code, remove bh
+         */
+        if (s->watch) {
+            AioContext *ctx = qemu_get_current_aio_context();
+
+            g_source_remove(s->watch);
+            s->watch = 0;
+            qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
+                                     NULL, NULL, false);
+
+            aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
+        }
+        break;
+    case CHR_EVENT_BREAK:
+    case CHR_EVENT_MUX_IN:
+    case CHR_EVENT_MUX_OUT:
+        /* Ignore */
+        break;
+    }
+
+    if (err) {
+        error_report_err(err);
+    }
+}
+
+static int net_vhost_user_init(NetClientState *peer, const char *device,
+                               const char *name, Chardev *chr,
+                               int queues)
+{
+    Error *err = NULL;
+    NetClientState *nc, *nc0 = NULL;
+    NetVhostUserState *s = NULL;
+    VhostUserState *user;
+    int i;
+
+    assert(name);
+    assert(queues > 0);
+
+    user = g_new0(struct VhostUserState, 1);
+    for (i = 0; i < queues; i++) {
+        nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
+        snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
+                 i, chr->label);
+        nc->queue_index = i;
+        if (!nc0) {
+            nc0 = nc;
+            s = DO_UPCAST(NetVhostUserState, nc, nc);
+            if (!qemu_chr_fe_init(&s->chr, chr, &err) ||
+                !vhost_user_init(user, &s->chr, &err)) {
+                error_report_err(err);
+                goto err;
+            }
+        }
+        s = DO_UPCAST(NetVhostUserState, nc, nc);
+        s->vhost_user = user;
+    }
+
+    s = DO_UPCAST(NetVhostUserState, nc, nc0);
+    do {
+        if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
+            error_report_err(err);
+            goto err;
+        }
+        qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
+                                 net_vhost_user_event, NULL, nc0->name, NULL,
+                                 true);
+    } while (!s->started);
+
+    assert(s->vhost_net);
+
+    return 0;
+
+err:
+    if (user) {
+        vhost_user_cleanup(user);
+        g_free(user);
+        if (s) {
+            s->vhost_user = NULL;
+        }
+    }
+    if (nc0) {
+        qemu_del_net_client(nc0);
+    }
+
+    return -1;
+}
+
+static Chardev *net_vhost_claim_chardev(
+    const NetdevVhostUserOptions *opts, Error **errp)
+{
+    Chardev *chr = qemu_chr_find(opts->chardev);
+
+    if (chr == NULL) {
+        error_setg(errp, "chardev \"%s\" not found", opts->chardev);
+        return NULL;
+    }
+
+    if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
+        error_setg(errp, "chardev \"%s\" is not reconnectable",
+                   opts->chardev);
+        return NULL;
+    }
+    if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
+        error_setg(errp, "chardev \"%s\" does not support FD passing",
+                   opts->chardev);
+        return NULL;
+    }
+
+    return chr;
+}
+
+int net_init_vhost_user(const Netdev *netdev, const char *name,
+                        NetClientState *peer, Error **errp)
+{
+    int queues;
+    const NetdevVhostUserOptions *vhost_user_opts;
+    Chardev *chr;
+
+    assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
+    vhost_user_opts = &netdev->u.vhost_user;
+
+    chr = net_vhost_claim_chardev(vhost_user_opts, errp);
+    if (!chr) {
+        return -1;
+    }
+
+    queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
+    if (queues < 1 || queues > MAX_QUEUE_NUM) {
+        error_setg(errp,
+                   "vhost-user number of queues must be in range [1, %d]",
+                   MAX_QUEUE_NUM);
+        return -1;
+    }
+
+    return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
+}