vhost-vsock: add vhost-vsock-common abstraction

This patch prepares the introduction of vhost-user-vsock, moving
the common code usable for both vhost-vsock and vhost-user-vsock
devices, in the new vhost-vsock-common parent class.

While moving the code, fixed checkpatch warnings about block comments.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20200522122512.87413-2-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 258 insertions, 0 deletions

diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-common.c
new file mode 100644
index 0000000000..5b2ebf3496
--- /dev/null
+++ b/hw/virtio/vhost-vsock-common.c
@@ -0,0 +1,258 @@
+/*
+ * Parent class for vhost-vsock devices
+ *
+ * Copyright 2015-2020 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "standard-headers/linux/virtio_vsock.h"
+#include "qapi/error.h"
+#include "hw/virtio/virtio-access.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/vhost-vsock.h"
+#include "qemu/iov.h"
+#include "monitor/monitor.h"
+
+int vhost_vsock_common_start(VirtIODevice *vdev)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    int ret;
+    int i;
+
+    if (!k->set_guest_notifiers) {
+        error_report("binding does not support guest notifiers");
+        return -ENOSYS;
+    }
+
+    ret = vhost_dev_enable_notifiers(&vvc->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error enabling host notifiers: %d", -ret);
+        return ret;
+    }
+
+    ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, true);
+    if (ret < 0) {
+        error_report("Error binding guest notifier: %d", -ret);
+        goto err_host_notifiers;
+    }
+
+    vvc->vhost_dev.acked_features = vdev->guest_features;
+    ret = vhost_dev_start(&vvc->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error starting vhost: %d", -ret);
+        goto err_guest_notifiers;
+    }
+
+    /*
+     * guest_notifier_mask/pending not used yet, so just unmask
+     * everything here.  virtio-pci will do the right thing by
+     * enabling/disabling irqfd.
+     */
+    for (i = 0; i < vvc->vhost_dev.nvqs; i++) {
+        vhost_virtqueue_mask(&vvc->vhost_dev, vdev, i, false);
+    }
+
+    return 0;
+
+err_guest_notifiers:
+    k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false);
+err_host_notifiers:
+    vhost_dev_disable_notifiers(&vvc->vhost_dev, vdev);
+    return ret;
+}
+
+void vhost_vsock_common_stop(VirtIODevice *vdev)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    int ret;
+
+    if (!k->set_guest_notifiers) {
+        return;
+    }
+
+    vhost_dev_stop(&vvc->vhost_dev, vdev);
+
+    ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false);
+    if (ret < 0) {
+        error_report("vhost guest notifier cleanup failed: %d", ret);
+        return;
+    }
+
+    vhost_dev_disable_notifiers(&vvc->vhost_dev, vdev);
+}
+
+
+static void vhost_vsock_common_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    /* Do nothing */
+}
+
+static void vhost_vsock_common_guest_notifier_mask(VirtIODevice *vdev, int idx,
+                                            bool mask)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    vhost_virtqueue_mask(&vvc->vhost_dev, vdev, idx, mask);
+}
+
+static bool vhost_vsock_common_guest_notifier_pending(VirtIODevice *vdev,
+                                               int idx)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    return vhost_virtqueue_pending(&vvc->vhost_dev, idx);
+}
+
+static void vhost_vsock_common_send_transport_reset(VHostVSockCommon *vvc)
+{
+    VirtQueueElement *elem;
+    VirtQueue *vq = vvc->event_vq;
+    struct virtio_vsock_event event = {
+        .id = cpu_to_le32(VIRTIO_VSOCK_EVENT_TRANSPORT_RESET),
+    };
+
+    elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
+    if (!elem) {
+        error_report("vhost-vsock missed transport reset event");
+        return;
+    }
+
+    if (elem->out_num) {
+        error_report("invalid vhost-vsock event virtqueue element with "
+                     "out buffers");
+        goto out;
+    }
+
+    if (iov_from_buf(elem->in_sg, elem->in_num, 0,
+                     &event, sizeof(event)) != sizeof(event)) {
+        error_report("vhost-vsock event virtqueue element is too short");
+        goto out;
+    }
+
+    virtqueue_push(vq, elem, sizeof(event));
+    virtio_notify(VIRTIO_DEVICE(vvc), vq);
+
+out:
+    g_free(elem);
+}
+
+static void vhost_vsock_common_post_load_timer_cleanup(VHostVSockCommon *vvc)
+{
+    if (!vvc->post_load_timer) {
+        return;
+    }
+
+    timer_del(vvc->post_load_timer);
+    timer_free(vvc->post_load_timer);
+    vvc->post_load_timer = NULL;
+}
+
+static void vhost_vsock_common_post_load_timer_cb(void *opaque)
+{
+    VHostVSockCommon *vvc = opaque;
+
+    vhost_vsock_common_post_load_timer_cleanup(vvc);
+    vhost_vsock_common_send_transport_reset(vvc);
+}
+
+int vhost_vsock_common_pre_save(void *opaque)
+{
+    VHostVSockCommon *vvc = opaque;
+
+    /*
+     * At this point, backend must be stopped, otherwise
+     * it might keep writing to memory.
+     */
+    assert(!vvc->vhost_dev.started);
+
+    return 0;
+}
+
+int vhost_vsock_common_post_load(void *opaque, int version_id)
+{
+    VHostVSockCommon *vvc = opaque;
+    VirtIODevice *vdev = VIRTIO_DEVICE(vvc);
+
+    if (virtio_queue_get_addr(vdev, 2)) {
+        /*
+         * Defer transport reset event to a vm clock timer so that virtqueue
+         * changes happen after migration has completed.
+         */
+        assert(!vvc->post_load_timer);
+        vvc->post_load_timer =
+            timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                         vhost_vsock_common_post_load_timer_cb,
+                         vvc);
+        timer_mod(vvc->post_load_timer, 1);
+    }
+    return 0;
+}
+
+void vhost_vsock_common_realize(VirtIODevice *vdev, const char *name)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    virtio_init(vdev, name, VIRTIO_ID_VSOCK,
+                sizeof(struct virtio_vsock_config));
+
+    /* Receive and transmit queues belong to vhost */
+    vvc->recv_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
+                                      vhost_vsock_common_handle_output);
+    vvc->trans_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
+                                       vhost_vsock_common_handle_output);
+
+    /* The event queue belongs to QEMU */
+    vvc->event_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
+                                       vhost_vsock_common_handle_output);
+
+    vvc->vhost_dev.nvqs = ARRAY_SIZE(vvc->vhost_vqs);
+    vvc->vhost_dev.vqs = vvc->vhost_vqs;
+
+    vvc->post_load_timer = NULL;
+}
+
+void vhost_vsock_common_unrealize(VirtIODevice *vdev)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    vhost_vsock_common_post_load_timer_cleanup(vvc);
+
+    virtio_delete_queue(vvc->recv_vq);
+    virtio_delete_queue(vvc->trans_vq);
+    virtio_delete_queue(vvc->event_vq);
+    virtio_cleanup(vdev);
+}
+
+static void vhost_vsock_common_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    vdc->guest_notifier_mask = vhost_vsock_common_guest_notifier_mask;
+    vdc->guest_notifier_pending = vhost_vsock_common_guest_notifier_pending;
+}
+
+static const TypeInfo vhost_vsock_common_info = {
+    .name = TYPE_VHOST_VSOCK_COMMON,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VHostVSockCommon),
+    .class_init = vhost_vsock_common_class_init,
+    .abstract = true,
+};
+
+static void vhost_vsock_common_register_types(void)
+{
+    type_register_static(&vhost_vsock_common_info);
+}
+
+type_init(vhost_vsock_common_register_types)