[RFC,02/19] hw/block: add boilerplate for vhost-user-rpmb device

diff --git a/include/hw/virtio/vhost-user-rpmb.h b/include/hw/virtio/vhost-user-rpmb.h
new file mode 100644
index 000000000000..7e5988127dc2
--- /dev/null
+++ b/include/hw/virtio/vhost-user-rpmb.h
@@ -0,0 +1,46 @@ 
+/*
+ * vhost-user-rpmb virtio device
+ *
+ * Copyright (c) 2020 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef _VHOST_USER_RPMB_H_
+#define _VHOST_USER_RPMB_H_
+
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+#include "chardev/char-fe.h"
+
+#define TYPE_VHOST_USER_RPMB "vhost-user-rpmb-device"
+#define VHOST_USER_RPMB(obj) \
+        OBJECT_CHECK(VHostUserRPMB, (obj), TYPE_VHOST_USER_RPMB)
+
+/* This is defined in the VIRTIO spec */
+struct virtio_rpmb_config {
+    uint8_t capacity;
+    uint8_t max_wr_cnt;
+    uint8_t max_rd_cnt;
+};
+
+typedef struct {
+    CharBackend chardev;
+    struct virtio_rpmb_config config;
+} VHostUserRPMBConf;
+
+typedef struct {
+    /*< private >*/
+    VirtIODevice parent;
+    VHostUserRPMBConf conf;
+    struct vhost_virtqueue *vhost_vq;
+    struct vhost_dev vhost_dev;
+    VhostUserState vhost_user;
+    VirtQueue *req_vq;
+    bool connected;
+    /*< public >*/
+} VHostUserRPMB;
+
+
+#endif /* _VHOST_USER_RPMB_H_ */
diff --git a/hw/block/vhost-user-rpmb.c b/hw/block/vhost-user-rpmb.c
new file mode 100644
index 000000000000..de243e7a53a0
--- /dev/null
+++ b/hw/block/vhost-user-rpmb.c
@@ -0,0 +1,333 @@ 
+/*
+ * Vhost-user RPMB virtio device
+ *
+ * This is the boilerplate for instantiating a vhost-user device
+ * implementing a Replay Protected Memory Block (RPMB) device. This is
+ * a type of flash chip that is protected from replay attacks and used
+ * for tamper resistant storage. The actual back-end for this driver
+ * is the vhost-user-rpmb daemon. The code here just connects up the
+ * device in QEMU and allows it to be instantiated.
+ *
+ * Copyright (c) 2020 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/vhost-user-rpmb.h"
+#include "qemu/error-report.h"
+
+/* currently there is no RPMB driver in Linux */
+#define VIRTIO_ID_RPMB         28 /* virtio RPMB */
+
+static void vurpmb_get_config(VirtIODevice *vdev, uint8_t *config)
+{
+    /* this somehow needs to come from the vhost-user daemon */
+}
+
+static void vurpmb_start(VirtIODevice *vdev)
+{
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(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;
+    }
+
+    ret = vhost_dev_enable_notifiers(&rpmb->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error enabling host notifiers: %d", -ret);
+        return;
+    }
+
+    ret = k->set_guest_notifiers(qbus->parent, rpmb->vhost_dev.nvqs, true);
+    if (ret < 0) {
+        error_report("Error binding guest notifier: %d", -ret);
+        goto err_host_notifiers;
+    }
+
+    rpmb->vhost_dev.acked_features = vdev->guest_features;
+    ret = vhost_dev_start(&rpmb->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error starting vhost-user-rpmb: %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 < rpmb->vhost_dev.nvqs; i++) {
+        vhost_virtqueue_mask(&rpmb->vhost_dev, vdev, i, false);
+    }
+
+    return;
+
+err_guest_notifiers:
+    k->set_guest_notifiers(qbus->parent, rpmb->vhost_dev.nvqs, false);
+err_host_notifiers:
+    vhost_dev_disable_notifiers(&rpmb->vhost_dev, vdev);
+}
+
+static void vurpmb_stop(VirtIODevice *vdev)
+{
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(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(&rpmb->vhost_dev, vdev);
+
+    ret = k->set_guest_notifiers(qbus->parent, rpmb->vhost_dev.nvqs, false);
+    if (ret < 0) {
+        error_report("vhost guest notifier cleanup failed: %d", ret);
+        return;
+    }
+
+    vhost_dev_disable_notifiers(&rpmb->vhost_dev, vdev);
+}
+
+static void vurpmb_set_status(VirtIODevice *vdev, uint8_t status)
+{
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
+
+    if (!vdev->vm_running) {
+        should_start = false;
+    }
+
+    if (rpmb->vhost_dev.started == should_start) {
+        return;
+    }
+
+    if (should_start) {
+        vurpmb_start(vdev);
+    } else {
+        vurpmb_stop(vdev);
+    }
+}
+
+static uint64_t vurpmb_get_features(VirtIODevice *vdev,
+                                      uint64_t requested_features,
+                                      Error **errp)
+{
+    /* No feature bits used yet */
+    return requested_features;
+}
+
+static void vurpmb_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    /*
+     * Not normally called; it's the daemon that handles the queue;
+     * however virtio's cleanup path can call this.
+     */
+}
+
+static void vurpmb_guest_notifier_mask(VirtIODevice *vdev, int idx,
+                                            bool mask)
+{
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+    vhost_virtqueue_mask(&rpmb->vhost_dev, vdev, idx, mask);
+}
+
+static bool vurpmb_guest_notifier_pending(VirtIODevice *vdev, int idx)
+{
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+    return vhost_virtqueue_pending(&rpmb->vhost_dev, idx);
+}
+
+/*
+ * Chardev connect/disconnect events
+ */
+
+static int vurpmb_handle_config_change(struct vhost_dev *dev)
+{
+    int ret;
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(dev->vdev);
+
+    ret = vhost_dev_get_config(dev, (uint8_t *)&rpmb->conf.config,
+                               sizeof(struct virtio_rpmb_config));
+    if (ret < 0) {
+        error_report("get config space failed");
+        return -1;
+    }
+
+    return 0;
+}
+
+const VhostDevConfigOps rpmb_ops = {
+    .vhost_dev_config_notifier = vurpmb_handle_config_change,
+};
+
+static int vurpmb_connect(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+
+    if (rpmb->connected) {
+        return 0;
+    }
+    rpmb->connected = true;
+
+    /* restore vhost state */
+    if (virtio_device_started(vdev, vdev->status)) {
+        vurpmb_start(vdev);
+    }
+
+    return 0;
+}
+
+static void vurpmb_disconnect(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+
+    if (!rpmb->connected) {
+        return;
+    }
+    rpmb->connected = false;
+
+    if (rpmb->vhost_dev.started) {
+        vurpmb_stop(vdev);
+    }
+
+    vhost_dev_cleanup(&rpmb->vhost_dev);
+}
+
+static void vurpmb_event(void *opaque, QEMUChrEvent event)
+{
+    DeviceState *dev = opaque;
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(vdev);
+
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        if (vurpmb_connect(dev) < 0) {
+            qemu_chr_fe_disconnect(&rpmb->conf.chardev);
+            return;
+        }
+        break;
+    case CHR_EVENT_CLOSED:
+        vurpmb_disconnect(dev);
+        break;
+    case CHR_EVENT_BREAK:
+    case CHR_EVENT_MUX_IN:
+    case CHR_EVENT_MUX_OUT:
+        /* Ignore */
+        break;
+    }
+}
+
+static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserRPMB *rpmb)
+{
+    vhost_user_cleanup(&rpmb->vhost_user);
+    virtio_delete_queue(rpmb->req_vq);
+    virtio_cleanup(vdev);
+    g_free(rpmb->vhost_dev.vqs);
+    rpmb->vhost_dev.vqs = NULL;
+}
+
+
+static void vurpmb_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(dev);
+    int ret;
+
+    if (!rpmb->conf.chardev.chr) {
+        error_setg(errp, "missing chardev");
+        return;
+    }
+
+    if (!vhost_user_init(&rpmb->vhost_user, &rpmb->conf.chardev, errp)) {
+        return;
+    }
+
+    virtio_init(vdev, "vhost-user-rpmb", VIRTIO_ID_RPMB,
+                sizeof(struct virtio_rpmb_config));
+
+    /* One request queue, 4 elements in case we don't do indirect */
+    rpmb->req_vq = virtio_add_queue(vdev, 4, vurpmb_handle_output);
+    rpmb->vhost_dev.nvqs = 1;
+    rpmb->vhost_dev.vqs = g_new0(struct vhost_virtqueue, rpmb->vhost_dev.nvqs);
+    ret = vhost_dev_init(&rpmb->vhost_dev, &rpmb->vhost_user,
+                         VHOST_BACKEND_TYPE_USER, 0);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "vhost_dev_init failed");
+        do_vhost_user_cleanup(vdev, rpmb);
+    }
+
+    /*
+     * At this point the next event we will get is a connection from
+     * the daemon on the control socket.
+     */
+
+    qemu_chr_fe_set_handlers(&rpmb->conf.chardev,  NULL, NULL, vurpmb_event,
+                             NULL, (void *)dev, NULL, true);
+
+    return;
+}
+
+static void vurpmb_device_unrealize(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRPMB *rpmb = VHOST_USER_RPMB(dev);
+
+    /* This will stop vhost backend if appropriate. */
+    vurpmb_set_status(vdev, 0);
+
+    do_vhost_user_cleanup(vdev, rpmb);
+}
+
+static const VMStateDescription vurpmb_vmstate = {
+    .name = "vhost-user-rpmb",
+    .unmigratable = 1,
+};
+
+static Property vurpmb_properties[] = {
+    DEFINE_PROP_CHR("chardev", VHostUserRPMB, conf.chardev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vurpmb_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    device_class_set_props(dc, vurpmb_properties);
+    dc->vmsd = &vurpmb_vmstate;
+    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
+    vdc->realize = vurpmb_device_realize;
+    vdc->unrealize = vurpmb_device_unrealize;
+    vdc->get_features = vurpmb_get_features;
+    vdc->get_config = vurpmb_get_config;
+    vdc->set_status = vurpmb_set_status;
+    vdc->guest_notifier_mask = vurpmb_guest_notifier_mask;
+    vdc->guest_notifier_pending = vurpmb_guest_notifier_pending;
+}
+
+static const TypeInfo vurpmb_info = {
+    .name = TYPE_VHOST_USER_RPMB,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VHostUserRPMB),
+    .class_init = vurpmb_class_init,
+};
+
+static void vurpmb_register_types(void)
+{
+    type_register_static(&vurpmb_info);
+}
+
+type_init(vurpmb_register_types)
diff --git a/hw/block/Kconfig b/hw/block/Kconfig
index 2d17f481adc6..12e21870847a 100644
--- a/hw/block/Kconfig
+++ b/hw/block/Kconfig
@@ -38,5 +38,10 @@  config VHOST_USER_BLK
     default y if VIRTIO_PCI
     depends on VIRTIO && VHOST_USER && LINUX
 
+config VHOST_USER_RPMB
+    bool
+    default y
+    depends on VIRTIO && VHOST_USER
+
 config SWIM
     bool
diff --git a/hw/block/meson.build b/hw/block/meson.build
index 78cad8f7cba1..114222f18424 100644
--- a/hw/block/meson.build
+++ b/hw/block/meson.build
@@ -17,5 +17,6 @@  softmmu_ss.add(when: 'CONFIG_NVME_PCI', if_true: files('nvme.c'))
 
 specific_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-blk.c'))
 specific_ss.add(when: 'CONFIG_VHOST_USER_BLK', if_true: files('vhost-user-blk.c'))
+specific_ss.add(when: 'CONFIG_VHOST_USER_RPMB', if_true: files('vhost-user-rpmb.c'))
 
 subdir('dataplane')