virtio: add vhost-user-vsock base device

This patch introduces a vhost-user device for vsock, using the
vhost-vsock-common parent class.

The vhost-user-vsock device can be used to implement the virtio-vsock
device emulation in user-space.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20200522122512.87413-3-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

configure

@@ -7196,6 +7196,9 @@ if test "$vhost_crypto" = "yes" ; then
 fi
 if test "$vhost_vsock" = "yes" ; then
   echo "CONFIG_VHOST_VSOCK=y" >> $config_host_mak
+  if test "$vhost_user" = "yes" ; then
+    echo "CONFIG_VHOST_USER_VSOCK=y" >> $config_host_mak
+  fi
 fi
 if test "$vhost_kernel" = "yes" ; then
   echo "CONFIG_VHOST_KERNEL=y" >> $config_host_mak

hw/virtio/Makefile.objs

@@ -18,6 +18,7 @@ common-obj-$(call land,$(CONFIG_VIRTIO_PMEM),$(CONFIG_VIRTIO_PCI)) += virtio-pme
 obj-$(call land,$(CONFIG_VHOST_USER_FS),$(CONFIG_VIRTIO_PCI)) += vhost-user-fs-pci.o
 obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-common.o vhost-vsock.o
+obj-$(CONFIG_VHOST_USER_VSOCK) += vhost-vsock-common.o vhost-user-vsock.o
 
 ifeq ($(CONFIG_VIRTIO_PCI),y)
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-pci.o

hw/virtio/vhost-user-vsock.c

@@ -0,0 +1,181 @@
+/*
+ * Vhost-user vsock virtio device
+ *
+ * Copyright 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 "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/vhost-user-vsock.h"
+
+static const int user_feature_bits[] = {
+    VIRTIO_F_VERSION_1,
+    VIRTIO_RING_F_INDIRECT_DESC,
+    VIRTIO_RING_F_EVENT_IDX,
+    VIRTIO_F_NOTIFY_ON_EMPTY,
+    VHOST_INVALID_FEATURE_BIT
+};
+
+static void vuv_get_config(VirtIODevice *vdev, uint8_t *config)
+{
+    VHostUserVSock *vsock = VHOST_USER_VSOCK(vdev);
+
+    memcpy(config, &vsock->vsockcfg, sizeof(struct virtio_vsock_config));
+}
+
+static int vuv_handle_config_change(struct vhost_dev *dev)
+{
+    VHostUserVSock *vsock = VHOST_USER_VSOCK(dev->vdev);
+    int ret = vhost_dev_get_config(dev, (uint8_t *)&vsock->vsockcfg,
+                                   sizeof(struct virtio_vsock_config));
+    if (ret < 0) {
+        error_report("get config space failed");
+        return -1;
+    }
+
+    virtio_notify_config(dev->vdev);
+
+    return 0;
+}
+
+const VhostDevConfigOps vsock_ops = {
+    .vhost_dev_config_notifier = vuv_handle_config_change,
+};
+
+static void vuv_set_status(VirtIODevice *vdev, uint8_t status)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
+
+    if (!vdev->vm_running) {
+        should_start = false;
+    }
+
+    if (vvc->vhost_dev.started == should_start) {
+        return;
+    }
+
+    if (should_start) {
+        int ret = vhost_vsock_common_start(vdev);
+        if (ret < 0) {
+            return;
+        }
+    } else {
+        vhost_vsock_common_stop(vdev);
+    }
+}
+
+static uint64_t vuv_get_features(VirtIODevice *vdev,
+                                 uint64_t features,
+                                 Error **errp)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    return vhost_get_features(&vvc->vhost_dev, user_feature_bits, features);
+}
+
+static const VMStateDescription vuv_vmstate = {
+    .name = "vhost-user-vsock",
+    .unmigratable = 1,
+};
+
+static void vuv_device_realize(DeviceState *dev, Error **errp)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(dev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserVSock *vsock = VHOST_USER_VSOCK(dev);
+    int ret;
+
+    if (!vsock->conf.chardev.chr) {
+        error_setg(errp, "missing chardev");
+        return;
+    }
+
+    if (!vhost_user_init(&vsock->vhost_user, &vsock->conf.chardev, errp)) {
+        return;
+    }
+
+    vhost_vsock_common_realize(vdev, "vhost-user-vsock");
+
+    vhost_dev_set_config_notifier(&vvc->vhost_dev, &vsock_ops);
+
+    ret = vhost_dev_init(&vvc->vhost_dev, &vsock->vhost_user,
+                         VHOST_BACKEND_TYPE_USER, 0);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "vhost_dev_init failed");
+        goto err_virtio;
+    }
+
+    ret = vhost_dev_get_config(&vvc->vhost_dev, (uint8_t *)&vsock->vsockcfg,
+                               sizeof(struct virtio_vsock_config));
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "get config space failed");
+        goto err_vhost_dev;
+    }
+
+    return;
+
+err_vhost_dev:
+    vhost_dev_cleanup(&vvc->vhost_dev);
+err_virtio:
+    vhost_vsock_common_unrealize(vdev);
+    vhost_user_cleanup(&vsock->vhost_user);
+    return;
+}
+
+static void vuv_device_unrealize(DeviceState *dev)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(dev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserVSock *vsock = VHOST_USER_VSOCK(dev);
+
+    /* This will stop vhost backend if appropriate. */
+    vuv_set_status(vdev, 0);
+
+    vhost_dev_cleanup(&vvc->vhost_dev);
+
+    vhost_vsock_common_unrealize(vdev);
+
+    vhost_user_cleanup(&vsock->vhost_user);
+
+}
+
+static Property vuv_properties[] = {
+    DEFINE_PROP_CHR("chardev", VHostUserVSock, conf.chardev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vuv_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    device_class_set_props(dc, vuv_properties);
+    dc->vmsd = &vuv_vmstate;
+    vdc->realize = vuv_device_realize;
+    vdc->unrealize = vuv_device_unrealize;
+    vdc->get_features = vuv_get_features;
+    vdc->get_config = vuv_get_config;
+    vdc->set_status = vuv_set_status;
+}
+
+static const TypeInfo vuv_info = {
+    .name = TYPE_VHOST_USER_VSOCK,
+    .parent = TYPE_VHOST_VSOCK_COMMON,
+    .instance_size = sizeof(VHostUserVSock),
+    .class_init = vuv_class_init,
+};
+
+static void vuv_register_types(void)
+{
+    type_register_static(&vuv_info);
+}
+
+type_init(vuv_register_types)

include/hw/virtio/vhost-user-vsock.h

@@ -0,0 +1,36 @@
+/*
+ * Vhost-user vsock virtio device
+ *
+ * Copyright 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.
+ */
+
+#ifndef _QEMU_VHOST_USER_VSOCK_H
+#define _QEMU_VHOST_USER_VSOCK_H
+
+#include "hw/virtio/vhost-vsock-common.h"
+#include "hw/virtio/vhost-user.h"
+#include "standard-headers/linux/virtio_vsock.h"
+
+#define TYPE_VHOST_USER_VSOCK "vhost-user-vsock-device"
+#define VHOST_USER_VSOCK(obj) \
+        OBJECT_CHECK(VHostUserVSock, (obj), TYPE_VHOST_USER_VSOCK)
+
+typedef struct {
+    CharBackend chardev;
+} VHostUserVSockConf;
+
+typedef struct {
+    /*< private >*/
+    VHostVSockCommon parent;
+    VhostUserState vhost_user;
+    VHostUserVSockConf conf;
+    struct virtio_vsock_config vsockcfg;
+
+    /*< public >*/
+} VHostUserVSock;
+
+#endif /* _QEMU_VHOST_USER_VSOCK_H */