[PATCH 0/5] virtio: Add vhost-user based RNG service

[PATCH 0/5] virtio: Add vhost-user based RNG service

[Mathieu Poirier]

Hi all,

This sets adds a vhost-user based random number generator (RNG),
similar to what has been done for i2c and virtiofsd.  In fact
the implementation for vhost-user-rng and vhost-user-rng-pci
follow what was done for vhost-user-i2c.

Applies cleanly to git://git.qemu.org/qemu.git master (52848929b70d).

Regards,
Mathieu

Mathieu Poirier (5):
  vhost-user-rng: Add vhost-user-rng implementation
  vhost-user-rng-pci: Add vhost-user-rng-pci implementation
  vhost-user-rng: backend: Add RNG vhost-user daemon implementation
  docs: Add documentation for vhost based RNG implementation
  MAINTAINERS: Add maintainer for vhost-user RNG implementation

 MAINTAINERS                              |   9 +
 docs/tools/vhost-user-rng.rst            |  74 +++++
 hw/virtio/Kconfig                        |   5 +
 hw/virtio/meson.build                    |   2 +
 hw/virtio/vhost-user-rng-pci.c           |  79 +++++
 hw/virtio/vhost-user-rng.c               | 294 +++++++++++++++++
 include/hw/virtio/vhost-user-rng.h       |  33 ++
 tools/meson.build                        |   8 +
 tools/vhost-user-rng/50-qemu-rng.json.in |   5 +
 tools/vhost-user-rng/main.c              | 403 +++++++++++++++++++++++
 tools/vhost-user-rng/meson.build         |  10 +
 11 files changed, 922 insertions(+)
 create mode 100644 docs/tools/vhost-user-rng.rst
 create mode 100644 hw/virtio/vhost-user-rng-pci.c
 create mode 100644 hw/virtio/vhost-user-rng.c
 create mode 100644 include/hw/virtio/vhost-user-rng.h
 create mode 100644 tools/vhost-user-rng/50-qemu-rng.json.in
 create mode 100644 tools/vhost-user-rng/main.c
 create mode 100644 tools/vhost-user-rng/meson.build

-- 
2.25.1

[PATCH 1/5] vhost-user-rng: Add vhost-user-rng implementation

[Mathieu Poirier]

Following in the footsteps of what whas done for vhost-user-i2c
and virtiofsd, introduce a random number generator (RNG) backend
that communicates with a vhost-user server to retrieve entropy.
That way another VMM could be using the same vhost-user daemon and
avoid having to write yet another RNG driver.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 hw/virtio/Kconfig                  |   5 +
 hw/virtio/meson.build              |   1 +
 hw/virtio/vhost-user-rng.c         | 294 +++++++++++++++++++++++++++++
 include/hw/virtio/vhost-user-rng.h |  33 ++++
 4 files changed, 333 insertions(+)
 create mode 100644 hw/virtio/vhost-user-rng.c
 create mode 100644 include/hw/virtio/vhost-user-rng.h

diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
index 0eda25c4e1bf..69066ab14e6d 100644
--- a/hw/virtio/Kconfig
+++ b/hw/virtio/Kconfig
@@ -58,3 +58,8 @@ config VIRTIO_MEM
     depends on LINUX
     depends on VIRTIO_MEM_SUPPORTED
     select MEM_DEVICE
+
+config VHOST_USER_RNG
+    bool
+    default y
+    depends on VIRTIO && VHOST_USER
diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index fbff9bc9d4de..e386791f2a05 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -25,6 +25,7 @@ virtio_ss.add(when: 'CONFIG_VHOST_USER_VSOCK', if_true: files('vhost-user-vsock.
 virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: files('virtio-rng.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: files('virtio-iommu.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-mem.c'))
+virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: files('vhost-user-rng.c'))
 
 virtio_pci_ss = ss.source_set()
 virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-pci.c'))
diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c
new file mode 100644
index 000000000000..78447e8d3791
--- /dev/null
+++ b/hw/virtio/vhost-user-rng.c
@@ -0,0 +1,294 @@
+/*
+ * Vhost-user RNG virtio device
+ *
+ * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * Implementation seriously tailored on vhost-user-i2c.c
+ *
+ * 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-rng.h"
+#include "qemu/error-report.h"
+#include "standard-headers/linux/virtio_ids.h"
+
+static void vu_rng_start(VirtIODevice *vdev)
+{
+    VHostUserRNG *rng = VHOST_USER_RNG(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(&rng->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error enabling host notifiers: %d", -ret);
+        return;
+    }
+
+    ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, true);
+    if (ret < 0) {
+        error_report("Error binding guest notifier: %d", -ret);
+        goto err_host_notifiers;
+    }
+
+    rng->vhost_dev.acked_features = vdev->guest_features;
+    ret = vhost_dev_start(&rng->vhost_dev, vdev);
+    if (ret < 0) {
+        error_report("Error starting vhost-user-rng: %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 < rng->vhost_dev.nvqs; i++) {
+        vhost_virtqueue_mask(&rng->vhost_dev, vdev, i, false);
+    }
+
+    return;
+
+err_guest_notifiers:
+    k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
+err_host_notifiers:
+    vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
+}
+
+static void vu_rng_stop(VirtIODevice *vdev)
+{
+    VHostUserRNG *rng = VHOST_USER_RNG(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(&rng->vhost_dev, vdev);
+
+    ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
+    if (ret < 0) {
+        error_report("vhost guest notifier cleanup failed: %d", ret);
+        return;
+    }
+
+    vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
+}
+
+static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status)
+{
+    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
+    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
+
+    if (!vdev->vm_running) {
+        should_start = false;
+    }
+
+    if (rng->vhost_dev.started == should_start) {
+        return;
+    }
+
+    if (should_start) {
+        vu_rng_start(vdev);
+    } else {
+        vu_rng_stop(vdev);
+    }
+}
+
+static uint64_t vu_rng_get_features(VirtIODevice *vdev,
+                                    uint64_t requested_features, Error **errp)
+{
+    /* No feature bits used yet */
+    return requested_features;
+}
+
+static void vu_rng_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 vu_rng_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
+{
+    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
+
+    vhost_virtqueue_mask(&rng->vhost_dev, vdev, idx, mask);
+}
+
+static bool vu_rng_guest_notifier_pending(VirtIODevice *vdev, int idx)
+{
+    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
+
+    return vhost_virtqueue_pending(&rng->vhost_dev, idx);
+}
+
+static void vu_rng_connect(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
+
+    if (rng->connected) {
+        return;
+    }
+
+    rng->connected = true;
+
+    /* restore vhost state */
+    if (virtio_device_started(vdev, vdev->status)) {
+        vu_rng_start(vdev);
+    }
+}
+
+static void vu_rng_disconnect(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRNG *rng = VHOST_USER_RNG(vdev);
+
+    if (!rng->connected) {
+        return;
+    }
+
+    rng->connected = false;
+
+    if (rng->vhost_dev.started) {
+        vu_rng_stop(vdev);
+    }
+}
+
+static void vu_rng_event(void *opaque, QEMUChrEvent event)
+{
+    DeviceState *dev = opaque;
+
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        vu_rng_connect(dev);
+        break;
+    case CHR_EVENT_CLOSED:
+        vu_rng_disconnect(dev);
+        break;
+    case CHR_EVENT_BREAK:
+    case CHR_EVENT_MUX_IN:
+    case CHR_EVENT_MUX_OUT:
+        /* Ignore */
+        break;
+    }
+}
+
+static void vu_rng_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRNG *rng = VHOST_USER_RNG(dev);
+    int ret;
+
+    if (!rng->chardev.chr) {
+        error_setg(errp, "missing chardev");
+        return;
+    }
+
+    if (!vhost_user_init(&rng->vhost_user, &rng->chardev, errp)) {
+        return;
+    }
+
+    virtio_init(vdev, "vhost-user-rng", VIRTIO_ID_RNG, 0);
+
+    rng->req_vq = virtio_add_queue(vdev, 4, vu_rng_handle_output);
+    if (!rng->req_vq) {
+        error_setg_errno(errp, -1, "virtio_add_queue() failed");
+        goto virtio_add_queue_failed;
+    }
+
+    rng->vhost_dev.nvqs = 1;
+    rng->vhost_dev.vqs = g_new0(struct vhost_virtqueue, rng->vhost_dev.nvqs);
+    if (!rng->vhost_dev.vqs) {
+        error_setg_errno(errp, -1, "memory allocation failed");
+        goto vhost_dev_init_failed;
+    }
+
+    ret = vhost_dev_init(&rng->vhost_dev, &rng->vhost_user,
+                         VHOST_BACKEND_TYPE_USER, 0);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "vhost_dev_init() failed");
+        goto vhost_dev_init_failed;
+    }
+
+    qemu_chr_fe_set_handlers(&rng->chardev, NULL, NULL, vu_rng_event, NULL,
+                             dev, NULL, true);
+
+    return;
+
+vhost_dev_init_failed:
+    virtio_delete_queue(rng->req_vq);
+virtio_add_queue_failed:
+    virtio_cleanup(vdev);
+    vhost_user_cleanup(&rng->vhost_user);
+}
+
+static void vu_rng_device_unrealize(DeviceState *dev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VHostUserRNG *rng = VHOST_USER_RNG(dev);
+
+    vu_rng_set_status(vdev, 0);
+
+    vhost_dev_cleanup(&rng->vhost_dev);
+    g_free(rng->vhost_dev.vqs);
+    rng->vhost_dev.vqs = NULL;
+    virtio_delete_queue(rng->req_vq);
+    virtio_cleanup(vdev);
+    vhost_user_cleanup(&rng->vhost_user);
+}
+
+static const VMStateDescription vu_rng_vmstate = {
+    .name = "vhost-user-rng",
+    .unmigratable = 1,
+};
+
+static Property vu_rng_properties[] = {
+    DEFINE_PROP_CHR("chardev", VHostUserRNG, chardev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vu_rng_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    device_class_set_props(dc, vu_rng_properties);
+    dc->vmsd = &vu_rng_vmstate;
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+
+    vdc->realize = vu_rng_device_realize;
+    vdc->unrealize = vu_rng_device_unrealize;
+    vdc->get_features = vu_rng_get_features;
+    vdc->set_status = vu_rng_set_status;
+    vdc->guest_notifier_mask = vu_rng_guest_notifier_mask;
+    vdc->guest_notifier_pending = vu_rng_guest_notifier_pending;
+}
+
+static const TypeInfo vu_rng_info = {
+    .name = TYPE_VHOST_USER_RNG,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VHostUserRNG),
+    .class_init = vu_rng_class_init,
+};
+
+static void vu_rng_register_types(void)
+{
+    type_register_static(&vu_rng_info);
+}
+
+type_init(vu_rng_register_types)
diff --git a/include/hw/virtio/vhost-user-rng.h b/include/hw/virtio/vhost-user-rng.h
new file mode 100644
index 000000000000..071539996d1d
--- /dev/null
+++ b/include/hw/virtio/vhost-user-rng.h
@@ -0,0 +1,33 @@
+/*
+ * Vhost-user RNG virtio device
+ *
+ * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef _QEMU_VHOST_USER_RNG_H
+#define _QEMU_VHOST_USER_RNG_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_RNG "vhost-user-rng"
+OBJECT_DECLARE_SIMPLE_TYPE(VHostUserRNG, VHOST_USER_RNG)
+
+struct VHostUserRNG {
+    /*< private >*/
+    VirtIODevice parent;
+    CharBackend chardev;
+    struct vhost_virtqueue *vhost_vq;
+    struct vhost_dev vhost_dev;
+    VhostUserState vhost_user;
+    VirtQueue *req_vq;
+    bool connected;
+
+    /*< public >*/
+};
+
+#endif /* _QEMU_VHOST_USER_RNG_H */
-- 
2.25.1

[PATCH 2/5] vhost-user-rng-pci: Add vhost-user-rng-pci implementation

[Mathieu Poirier]

This patch provides a PCI bus interface to the vhost-user-rng backed.
The implentation is similar to what was done for vhost-user-i2c-pci and
vhost-user-fs-pci.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 hw/virtio/meson.build          |  1 +
 hw/virtio/vhost-user-rng-pci.c | 79 ++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 hw/virtio/vhost-user-rng-pci.c

diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index e386791f2a05..1430b370e64d 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -26,6 +26,7 @@ virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: files('virtio-rng.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: files('virtio-iommu.c'))
 virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-mem.c'))
 virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: files('vhost-user-rng.c'))
+virtio_ss.add(when: ['CONFIG_VHOST_USER_RNG', 'CONFIG_VIRTIO_PCI'], if_true: files('vhost-user-rng-pci.c'))
 
 virtio_pci_ss = ss.source_set()
 virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-pci.c'))
diff --git a/hw/virtio/vhost-user-rng-pci.c b/hw/virtio/vhost-user-rng-pci.c
new file mode 100644
index 000000000000..ffff2de39fd4
--- /dev/null
+++ b/hw/virtio/vhost-user-rng-pci.c
@@ -0,0 +1,79 @@
+/*
+ * Vhost-user RNG virtio device PCI glue
+ *
+ * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/vhost-user-rng.h"
+#include "virtio-pci.h"
+
+struct VHostUserRNGPCI {
+    VirtIOPCIProxy parent_obj;
+    VHostUserRNG vdev;
+};
+
+typedef struct VHostUserRNGPCI VHostUserRNGPCI;
+
+#define TYPE_VHOST_USER_RNG_PCI "vhost-user-rng-pci-base"
+
+DECLARE_INSTANCE_CHECKER(VHostUserRNGPCI, VHOST_USER_RNG_PCI,
+                         TYPE_VHOST_USER_RNG_PCI)
+
+static Property vhost_user_rng_pci_properties[] = {
+    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
+                       DEV_NVECTORS_UNSPECIFIED),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vhost_user_rng_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
+{
+    VHostUserRNGPCI *dev = VHOST_USER_RNG_PCI(vpci_dev);
+    DeviceState *vdev = DEVICE(&dev->vdev);
+
+    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
+        vpci_dev->nvectors = 1;
+    }
+
+    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
+}
+
+static void vhost_user_rng_pci_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
+    PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
+    k->realize = vhost_user_rng_pci_realize;
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+    device_class_set_props(dc, vhost_user_rng_pci_properties);
+    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
+    pcidev_k->device_id = 0; /* Set by virtio-pci based on virtio id */
+    pcidev_k->revision = 0x00;
+    pcidev_k->class_id = PCI_CLASS_COMMUNICATION_OTHER;
+}
+
+static void vhost_user_rng_pci_instance_init(Object *obj)
+{
+    VHostUserRNGPCI *dev = VHOST_USER_RNG_PCI(obj);
+
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VHOST_USER_RNG);
+}
+
+static const VirtioPCIDeviceTypeInfo vhost_user_rng_pci_info = {
+    .base_name = TYPE_VHOST_USER_RNG_PCI,
+    .non_transitional_name = "vhost-user-rng-pci",
+    .instance_size = sizeof(VHostUserRNGPCI),
+    .instance_init = vhost_user_rng_pci_instance_init,
+    .class_init = vhost_user_rng_pci_class_init,
+};
+
+static void vhost_user_rng_pci_register(void)
+{
+    virtio_pci_types_register(&vhost_user_rng_pci_info);
+}
+
+type_init(vhost_user_rng_pci_register);
-- 
2.25.1

[PATCH 3/5] vhost-user-rng: backend: Add RNG vhost-user daemon implementation

[Mathieu Poirier]

This patch provides the vhost-user backend implementation to work
in tandem with the vhost-user-rng implementation of the QEMU VMM.

It uses the vhost-user API so that other VMM can re-use the interface
without having to write the driver again.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 tools/meson.build                        |   8 +
 tools/vhost-user-rng/50-qemu-rng.json.in |   5 +
 tools/vhost-user-rng/main.c              | 403 +++++++++++++++++++++++
 tools/vhost-user-rng/meson.build         |  10 +
 4 files changed, 426 insertions(+)
 create mode 100644 tools/vhost-user-rng/50-qemu-rng.json.in
 create mode 100644 tools/vhost-user-rng/main.c
 create mode 100644 tools/vhost-user-rng/meson.build

diff --git a/tools/meson.build b/tools/meson.build
index 3e5a0abfa29f..66b0a11fbb45 100644
--- a/tools/meson.build
+++ b/tools/meson.build
@@ -24,3 +24,11 @@ endif
 if have_virtiofsd
   subdir('virtiofsd')
 endif
+
+have_virtiorng = (have_system and
+    have_tools and
+    'CONFIG_LINUX' in config_host)
+
+if have_virtiorng
+  subdir('vhost-user-rng')
+endif
diff --git a/tools/vhost-user-rng/50-qemu-rng.json.in b/tools/vhost-user-rng/50-qemu-rng.json.in
new file mode 100644
index 000000000000..9186c3c6fe1d
--- /dev/null
+++ b/tools/vhost-user-rng/50-qemu-rng.json.in
@@ -0,0 +1,5 @@
+{
+  "description": "QEMU vhost-user-rng",
+  "type": "bridge",
+  "binary": "@libexecdir@/vhost-user-rng"
+}
diff --git a/tools/vhost-user-rng/main.c b/tools/vhost-user-rng/main.c
new file mode 100644
index 000000000000..ba7380b12659
--- /dev/null
+++ b/tools/vhost-user-rng/main.c
@@ -0,0 +1,403 @@
+/*
+ * VIRTIO RNG Emulation via vhost-user
+ *
+ * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#define G_LOG_DOMAIN "vhost-user-rng"
+#define G_LOG_USE_STRUCTURED 1
+
+#include <glib.h>
+#include <gio/gio.h>
+#include <gio/gunixsocketaddress.h>
+#include <glib-unix.h>
+#include <glib/gstdio.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <time.h>
+#include <unistd.h>
+#include <endian.h>
+#include <assert.h>
+
+#include "qemu/cutils.h"
+#include "subprojects/libvhost-user/libvhost-user-glib.h"
+#include "subprojects/libvhost-user/libvhost-user.h"
+
+#ifndef container_of
+#define container_of(ptr, type, member) ({                      \
+        const typeof(((type *) 0)->member) * __mptr = (ptr);     \
+        (type *) ((char *) __mptr - offsetof(type, member)); })
+#endif
+
+typedef struct {
+    VugDev dev;
+    struct itimerspec ts;
+    timer_t rate_limit_timer;
+    pthread_mutex_t rng_mutex;
+    pthread_cond_t rng_cond;
+    int64_t quota_remaining;
+    bool activate_timer;
+    GMainLoop *loop;
+} VuRNG;
+
+static gboolean print_cap, verbose;
+static gchar *source_path, *socket_path;
+static gint source_fd, socket_fd = -1;
+
+/* Defaults tailored on virtio-rng.c */
+static uint32_t period_ms = 1 << 16;
+static uint64_t max_bytes = INT64_MAX;
+
+static void check_rate_limit(union sigval sv)
+{
+    VuRNG *rng = sv.sival_ptr;
+    bool wakeup = false;
+
+    pthread_mutex_lock(&rng->rng_mutex);
+    /*
+     * The timer has expired and the guest has used all available
+     * antropy, which means function vu_rng_handle_request() is waiting
+     * on us.  As such wake it up once we're done here.
+     */
+    if (rng->quota_remaining == 0) {
+        wakeup = true;
+    }
+
+    /*
+     * Reset the antropy available to the guest and tell function
+     * vu_rng_handle_requests() to start the timer before using it.
+     */
+    rng->quota_remaining = max_bytes;
+    rng->activate_timer = true;
+    pthread_mutex_unlock(&rng->rng_mutex);
+
+    if (wakeup) {
+        pthread_cond_signal(&rng->rng_cond);
+    }
+}
+
+static void setup_timer(VuRNG *rng)
+{
+    struct sigevent sev;
+    int ret;
+
+    memset(&rng->ts, 0, sizeof(struct itimerspec));
+    rng->ts.it_value.tv_sec = period_ms / 1000;
+    rng->ts.it_value.tv_nsec = (period_ms % 1000) * 1000000;
+
+    /*
+     * Call function check_rate_limit() as if it was the start of
+     * a new thread when the timer expires.
+     */
+    sev.sigev_notify = SIGEV_THREAD;
+    sev.sigev_notify_function = check_rate_limit;
+    sev.sigev_value.sival_ptr = rng;
+    /* Needs to be NULL if defaults attributes are to be used. */
+    sev.sigev_notify_attributes = NULL;
+    ret = timer_create(CLOCK_MONOTONIC, &sev, &rng->rate_limit_timer);
+    if (ret < 0) {
+        fprintf(stderr, "timer_create() failed\n");
+    }
+
+}
+
+
+/* Virtio helpers */
+static uint64_t rng_get_features(VuDev *dev)
+{
+    if (verbose) {
+        g_info("%s: replying", __func__);
+    }
+    return 0;
+}
+
+static void rng_set_features(VuDev *dev, uint64_t features)
+{
+    if (verbose && features) {
+        g_autoptr(GString) s = g_string_new("Requested un-handled feature");
+        g_string_append_printf(s, " 0x%" PRIx64 "", features);
+        g_info("%s: %s", __func__, s->str);
+    }
+}
+
+static void vu_rng_handle_requests(VuDev *dev, int qidx)
+{
+    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+    VuVirtqElement *elem;
+    size_t to_read;
+    int len, ret;
+
+    for (;;) {
+        /* Get element in the vhost virtqueue */
+        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+        if (!elem) {
+            break;
+        }
+
+        /* Get the amount of antropy to read from the vhost server */
+        to_read = elem->in_sg[0].iov_len;
+
+        pthread_mutex_lock(&rng->rng_mutex);
+
+        /*
+         * We have consumed all entropy available for this time slice.
+         * Wait for the timer (check_rate_limit()) to tell us about the
+         * start of a new time slice.
+         */
+        if (rng->quota_remaining == 0) {
+            pthread_cond_wait(&rng->rng_cond, &rng->rng_mutex);
+        }
+
+        /* Start the timer if the last time slice has expired */
+        if (rng->activate_timer == true) {
+            rng->activate_timer = false;
+            ret = timer_settime(rng->rate_limit_timer, 0, &rng->ts, NULL);
+            if (ret < 0) {
+                fprintf(stderr, "timer_settime() failed\n");
+            }
+        }
+
+        /* Make sure we don't read more than it's available */
+        if (rng->quota_remaining < to_read) {
+            to_read = rng->quota_remaining;
+        }
+
+        len = read(source_fd, elem->in_sg[0].iov_base, to_read);
+
+        /* Simply return 0 if an error occurs */
+        if (len < 0) {
+            len = 0;
+        }
+
+        rng->quota_remaining -= len;
+
+        pthread_mutex_unlock(&rng->rng_mutex);
+
+        vu_queue_push(dev, vq, elem, len);
+        free(elem);
+    }
+
+    vu_queue_notify(dev, vq);
+}
+
+static void
+vu_rng_queue_set_started(VuDev *dev, int qidx, bool started)
+{
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+
+    g_debug("queue started %d:%d\n", qidx, started);
+
+    if (!qidx) {
+        vu_set_queue_handler(dev, vq, started ? vu_rng_handle_requests : NULL);
+    }
+}
+
+/*
+ * Any messages not handled here are processed by the libvhost library
+ * itself.
+ */
+static int rng_process_msg(VuDev *dev, VhostUserMsg *msg, int *do_reply)
+{
+    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
+
+    if (msg->request == VHOST_USER_NONE) {
+        g_main_loop_quit(rng->loop);
+        return 1;
+    }
+
+    return 0;
+}
+
+static const VuDevIface vuiface = {
+    .set_features = rng_set_features,
+    .get_features = rng_get_features,
+    .queue_set_started = vu_rng_queue_set_started,
+    .process_msg = rng_process_msg,
+};
+
+static gboolean hangup(gpointer user_data)
+{
+    GMainLoop *loop = (GMainLoop *) user_data;
+
+    g_printerr("%s: caught hangup/quit signal, quitting", __func__);
+    g_main_loop_quit(loop);
+    return true;
+}
+
+static void panic(VuDev *dev, const char *msg)
+{
+    g_critical("%s\n", msg);
+    exit(EXIT_FAILURE);
+}
+
+/* Print vhost-user.json backend program capabilities */
+static void print_capabilities(void)
+{
+    printf("{\n");
+    printf("  \"type\": \"RNG\"\n");
+    printf("  \"filename\": [ RNG source ]\n");
+    printf("}\n");
+}
+
+static GOptionEntry options[] = {
+    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &socket_path,
+      "Location of vhost-user Unix domain socket, incompatible with --fd",
+      "PATH" },
+    { "fd", 'f', 0, G_OPTION_ARG_INT, &socket_fd,
+      "Specify the backend file-descriptor, incompatible with --socket-path",
+      "FD" },
+    { "period", 'p', 0, G_OPTION_ARG_INT, &period_ms,
+      "Time needed (in ms) to transfer a maximum amount of byte", NULL },
+    { "max-bytes", 'm', 0, G_OPTION_ARG_INT64, &max_bytes,
+      "Maximum amount of byte that can be transferred in a period", NULL },
+    { "filename", 'n', 0, G_OPTION_ARG_FILENAME, &source_path,
+      "RNG source, defaults to /dev/urandom", "PATH" },
+    { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &print_cap,
+      "Output to stdout the backend capabilities in JSON format and exit",
+      NULL},
+    { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose,
+      "Be more verbose in output", NULL},
+    { NULL }
+};
+
+int main(int argc, char *argv[])
+{
+    GError *error = NULL;
+    GOptionContext *context;
+    g_autoptr(GSocket) socket = NULL;
+    char default_source[] = "/dev/urandom";
+    char *source = default_source;
+    VuRNG rng;
+
+    context = g_option_context_new("vhost-user emulation of RNG device");
+    g_option_context_add_main_entries(context, options, "vhost-user-rng");
+    if (!g_option_context_parse(context, &argc, &argv, &error)) {
+        g_printerr("option parsing failed: %s\n", error->message);
+        exit(1);
+    }
+
+    if (print_cap) {
+        print_capabilities();
+        exit(0);
+    }
+
+    if (!socket_path && socket_fd < 0) {
+        g_printerr("Please specify either --fd or --socket-path\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if (socket_path && socket_fd > 0) {
+        g_printerr("Either --fd or --socket-path, not both\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if (max_bytes > INT64_MAX) {
+        g_printerr("'max-bytes' parameter must be non-negative, "
+                   "and less than 2^63\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if (period_ms <= 0) {
+        g_printerr("'period' parameter expects a positive integer\n");
+        exit(EXIT_FAILURE);
+    }
+
+    /*
+     * Now create a vhost-user socket that we will receive messages
+     * on. Once we have our handler set up we can enter the glib main
+     * loop.
+     */
+    if (socket_path) {
+        g_autoptr(GSocketAddress) addr = g_unix_socket_address_new(socket_path);
+        g_autoptr(GSocket) bind_socket = g_socket_new(G_SOCKET_FAMILY_UNIX,
+                                                      G_SOCKET_TYPE_STREAM,
+                                                      G_SOCKET_PROTOCOL_DEFAULT,
+                                                      &error);
+
+        if (!g_socket_bind(bind_socket, addr, false, &error)) {
+            g_printerr("Failed to bind to socket at %s (%s).\n",
+                       socket_path, error->message);
+            exit(EXIT_FAILURE);
+        }
+        if (!g_socket_listen(bind_socket, &error)) {
+            g_printerr("Failed to listen on socket %s (%s).\n",
+                       socket_path, error->message);
+        }
+        g_message("awaiting connection to %s", socket_path);
+        socket = g_socket_accept(bind_socket, NULL, &error);
+        if (!socket) {
+            g_printerr("Failed to accept on socket %s (%s).\n",
+                       socket_path, error->message);
+        }
+    } else {
+        socket = g_socket_new_from_fd(socket_fd, &error);
+        if (!socket) {
+            g_printerr("Failed to connect to FD %d (%s).\n",
+                       socket_fd, error->message);
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    /* Overwrite default RNG source with what user provided, if any */
+    if (source_path) {
+        source = source_path;
+    }
+
+    source_fd = open(source, O_RDWR);
+    if (source_fd < 0) {
+        g_printerr("Failed to open RNG source %s\n", source);
+        g_socket_close(socket, &error);
+        unlink(socket_path);
+        exit(EXIT_FAILURE);
+    }
+
+    /* catch exit signals */
+    g_unix_signal_add(SIGHUP, hangup, rng.loop);
+    g_unix_signal_add(SIGINT, hangup, rng.loop);
+
+    /*
+     * Create the main loop first so all the various sources can be
+     * added. As well as catching signals we need to ensure vug_init
+     * can add it's GSource watches.
+     */
+    rng.loop = g_main_loop_new(NULL, FALSE);
+
+    if (!vug_init(&rng.dev, 1, g_socket_get_fd(socket),
+                  panic, &vuiface)) {
+        g_printerr("Failed to initialize libvhost-user-glib.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    rng.quota_remaining = max_bytes;
+    rng.activate_timer = true;
+    pthread_mutex_init(&rng.rng_mutex, NULL);
+    pthread_cond_init(&rng.rng_cond, NULL);
+    setup_timer(&rng);
+
+    if (verbose) {
+        g_info("period_ms: %d tv_sec: %ld tv_nsec: %lu\n",
+               period_ms, rng.ts.it_value.tv_sec, rng.ts.it_value.tv_nsec);
+    }
+
+    g_message("entering main loop, awaiting messages");
+    g_main_loop_run(rng.loop);
+    g_message("finished main loop, cleaning up");
+
+    g_main_loop_unref(rng.loop);
+    vug_deinit(&rng.dev);
+    timer_delete(rng.rate_limit_timer);
+    close(source_fd);
+    unlink(socket_path);
+}
diff --git a/tools/vhost-user-rng/meson.build b/tools/vhost-user-rng/meson.build
new file mode 100644
index 000000000000..4dc386daf335
--- /dev/null
+++ b/tools/vhost-user-rng/meson.build
@@ -0,0 +1,10 @@
+executable('vhost-user-rng', files(
+  'main.c'),
+  dependencies: [qemuutil, glib, gio, rt],
+  install: true,
+  install_dir: get_option('libexecdir'))
+
+configure_file(input: '50-qemu-rng.json.in',
+               output: '50-qemu-rng.json',
+               configuration: config_host,
+               install_dir: qemu_datadir / 'vhost-user')
-- 
2.25.1

[PATCH 4/5] docs: Add documentation for vhost based RNG implementation

[Mathieu Poirier]

Add description and example for the vhost-user based RNG implementation.
Tailored on Viresh Kumar's vhost-user-i2c documentation.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 docs/tools/vhost-user-rng.rst | 74 +++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 docs/tools/vhost-user-rng.rst

diff --git a/docs/tools/vhost-user-rng.rst b/docs/tools/vhost-user-rng.rst
new file mode 100644
index 000000000000..7f69d7bb3c58
--- /dev/null
+++ b/docs/tools/vhost-user-rng.rst
@@ -0,0 +1,74 @@
+QEMU vhost-user-rng - RNG emulation backend
+===========================================
+
+Synopsis
+--------
+
+**vhost-user-rng** [*OPTIONS*]
+
+Description
+-----------
+
+This program is a vhost-user backend that emulates a VirtIO random number
+generator (RNG).  It uses the host's random number generator pool,
+/dev/urandom by default but configurable at will, to satisfy requests from
+guests.
+
+This program is designed to work with QEMU's ``-device
+vhost-user-rng-pci`` but should work with any virtual machine monitor
+(VMM) that supports vhost-user. See the Examples section below.
+
+Options
+-------
+
+.. program:: vhost-user-rng
+
+.. option:: -h, --help
+
+  Print help.
+
+.. option:: -v, --verbose
+
+   Increase verbosity of output
+
+.. option:: -s, --socket-path=PATH
+
+  Listen on vhost-user UNIX domain socket at PATH. Incompatible with --fd.
+
+.. option:: -f, --fd=FDNUM
+
+  Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.
+  The file descriptor must already be listening for connections.
+  Incompatible with --socket-path.
+
+.. option:: -p, --period
+
+  Rate, in milliseconds, at which the RNG hardware can generate random data.
+  Used in conjunction with the --max-bytes option.
+
+.. option:: -m, --max-bytes
+
+  In conjuction with the --period parameter, provides the maximum number of byte
+  per milliseconds a RNG device can generate.
+
+Examples
+--------
+
+The daemon should be started first:
+
+::
+
+  host# vhost-user-rng --socket-path=rng.sock --period=1000 --max-bytes=4096
+
+The QEMU invocation needs to create a chardev socket the device can
+use to communicate as well as share the guests memory over a memfd.
+
+::
+
+  host# qemu-system								\
+      -chardev socket,path=$(PATH)/rng.sock,id=rng0				\
+      -device vhost-user-rng-pci,chardev=rng0					\
+      -m 4096 									\
+      -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on	\
+      -numa node,memdev=mem							\
+      ...
-- 
2.25.1

[PATCH 5/5] MAINTAINERS: Add maintainer for vhost-user RNG implementation

[Mathieu Poirier]

This patch adds entry for the vhost-user-rng related files.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 5f55404f2fae..6a0d61443571 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1937,6 +1937,15 @@ F: include/sysemu/rng*.h
 F: backends/rng*.c
 F: tests/qtest/virtio-rng-test.c
 
+vhost-user-rng
+M: Mathieu Poirier <mathieu.poirier@linaro.org>
+S: Supported
+F: docs/tools/vhost-user-rng.rst
+F: hw/virtio/vhost-user-rng.c
+F: hw/virtio/vhost-user-rng-pci.c
+F: include/hw/virtio/vhost-user-rng.h
+F: tools/vhost-user-rng/*
+
 virtio-crypto
 M: Gonglei <arei.gonglei@huawei.com>
 S: Supported
-- 
2.25.1

Re: [Stratos-dev] [PATCH 3/5] vhost-user-rng: backend: Add RNG vhost-user daemon implementation

[Joakim Bech]

On Tue, Jun 01, 2021 at 08:03:20PM +0000, Mathieu Poirier via Stratos-dev wrote:
> This patch provides the vhost-user backend implementation to work
> in tandem with the vhost-user-rng implementation of the QEMU VMM.
> 
> It uses the vhost-user API so that other VMM can re-use the interface
> without having to write the driver again.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>  tools/meson.build                        |   8 +
>  tools/vhost-user-rng/50-qemu-rng.json.in |   5 +
>  tools/vhost-user-rng/main.c              | 403 +++++++++++++++++++++++
>  tools/vhost-user-rng/meson.build         |  10 +
>  4 files changed, 426 insertions(+)
>  create mode 100644 tools/vhost-user-rng/50-qemu-rng.json.in
>  create mode 100644 tools/vhost-user-rng/main.c
>  create mode 100644 tools/vhost-user-rng/meson.build
> 
> diff --git a/tools/meson.build b/tools/meson.build
> index 3e5a0abfa29f..66b0a11fbb45 100644
> --- a/tools/meson.build
> +++ b/tools/meson.build
> @@ -24,3 +24,11 @@ endif
>  if have_virtiofsd
>    subdir('virtiofsd')
>  endif
> +
> +have_virtiorng = (have_system and
> +    have_tools and
> +    'CONFIG_LINUX' in config_host)
> +
> +if have_virtiorng
> +  subdir('vhost-user-rng')
> +endif
> diff --git a/tools/vhost-user-rng/50-qemu-rng.json.in b/tools/vhost-user-rng/50-qemu-rng.json.in
> new file mode 100644
> index 000000000000..9186c3c6fe1d
> --- /dev/null
> +++ b/tools/vhost-user-rng/50-qemu-rng.json.in
> @@ -0,0 +1,5 @@
> +{
> +  "description": "QEMU vhost-user-rng",
> +  "type": "bridge",
> +  "binary": "@libexecdir@/vhost-user-rng"
> +}
> diff --git a/tools/vhost-user-rng/main.c b/tools/vhost-user-rng/main.c
> new file mode 100644
> index 000000000000..ba7380b12659
> --- /dev/null
> +++ b/tools/vhost-user-rng/main.c
> @@ -0,0 +1,403 @@
> +/*
> + * VIRTIO RNG Emulation via vhost-user
> + *
> + * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#define G_LOG_DOMAIN "vhost-user-rng"
> +#define G_LOG_USE_STRUCTURED 1
> +
> +#include <glib.h>
> +#include <gio/gio.h>
> +#include <gio/gunixsocketaddress.h>
> +#include <glib-unix.h>
> +#include <glib/gstdio.h>
> +#include <pthread.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdbool.h>
> +#include <string.h>
> +#include <inttypes.h>
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <sys/mman.h>
> +#include <time.h>
> +#include <unistd.h>
> +#include <endian.h>
> +#include <assert.h>
> +
> +#include "qemu/cutils.h"
> +#include "subprojects/libvhost-user/libvhost-user-glib.h"
> +#include "subprojects/libvhost-user/libvhost-user.h"
> +
> +#ifndef container_of
> +#define container_of(ptr, type, member) ({                      \
> +        const typeof(((type *) 0)->member) * __mptr = (ptr);     \
> +        (type *) ((char *) __mptr - offsetof(type, member)); })
> +#endif
> +
> +typedef struct {
> +    VugDev dev;
> +    struct itimerspec ts;
> +    timer_t rate_limit_timer;
> +    pthread_mutex_t rng_mutex;
> +    pthread_cond_t rng_cond;
> +    int64_t quota_remaining;
> +    bool activate_timer;
> +    GMainLoop *loop;
> +} VuRNG;
> +
> +static gboolean print_cap, verbose;
> +static gchar *source_path, *socket_path;
> +static gint source_fd, socket_fd = -1;
> +
> +/* Defaults tailored on virtio-rng.c */
> +static uint32_t period_ms = 1 << 16;
> +static uint64_t max_bytes = INT64_MAX;
> +
> +static void check_rate_limit(union sigval sv)
> +{
> +    VuRNG *rng = sv.sival_ptr;
> +    bool wakeup = false;
> +
> +    pthread_mutex_lock(&rng->rng_mutex);
> +    /*
> +     * The timer has expired and the guest has used all available
> +     * antropy, which means function vu_rng_handle_request() is waiting
s/antropy/entropy/

I also found 'antropy' at two more locations in this patch (that made me
wonder).

> +     * on us.  As such wake it up once we're done here.
> +     */
> +    if (rng->quota_remaining == 0) {
> +        wakeup = true;
> +    }
> +
> +    /*
> +     * Reset the antropy available to the guest and tell function
> +     * vu_rng_handle_requests() to start the timer before using it.
> +     */
> +    rng->quota_remaining = max_bytes;
> +    rng->activate_timer = true;
> +    pthread_mutex_unlock(&rng->rng_mutex);
> +
> +    if (wakeup) {
> +        pthread_cond_signal(&rng->rng_cond);
> +    }
> +}
> +
> +static void setup_timer(VuRNG *rng)
> +{
> +    struct sigevent sev;
> +    int ret;
> +
> +    memset(&rng->ts, 0, sizeof(struct itimerspec));
> +    rng->ts.it_value.tv_sec = period_ms / 1000;
> +    rng->ts.it_value.tv_nsec = (period_ms % 1000) * 1000000;
> +
> +    /*
> +     * Call function check_rate_limit() as if it was the start of
> +     * a new thread when the timer expires.
> +     */
> +    sev.sigev_notify = SIGEV_THREAD;
> +    sev.sigev_notify_function = check_rate_limit;
> +    sev.sigev_value.sival_ptr = rng;
> +    /* Needs to be NULL if defaults attributes are to be used. */
> +    sev.sigev_notify_attributes = NULL;
> +    ret = timer_create(CLOCK_MONOTONIC, &sev, &rng->rate_limit_timer);
> +    if (ret < 0) {
> +        fprintf(stderr, "timer_create() failed\n");
> +    }
> +
> +}
> +
> +
> +/* Virtio helpers */
> +static uint64_t rng_get_features(VuDev *dev)
> +{
> +    if (verbose) {
> +        g_info("%s: replying", __func__);
> +    }
> +    return 0;
> +}
> +
> +static void rng_set_features(VuDev *dev, uint64_t features)
> +{
> +    if (verbose && features) {
> +        g_autoptr(GString) s = g_string_new("Requested un-handled feature");
> +        g_string_append_printf(s, " 0x%" PRIx64 "", features);
> +        g_info("%s: %s", __func__, s->str);
> +    }
> +}
> +
> +static void vu_rng_handle_requests(VuDev *dev, int qidx)
> +{
> +    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
> +    VuVirtq *vq = vu_get_queue(dev, qidx);
> +    VuVirtqElement *elem;
> +    size_t to_read;
> +    int len, ret;
> +
> +    for (;;) {
> +        /* Get element in the vhost virtqueue */
> +        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
> +        if (!elem) {
> +            break;
> +        }
> +
> +        /* Get the amount of antropy to read from the vhost server */
> +        to_read = elem->in_sg[0].iov_len;
> +
> +        pthread_mutex_lock(&rng->rng_mutex);
> +
> +        /*
> +         * We have consumed all entropy available for this time slice.
> +         * Wait for the timer (check_rate_limit()) to tell us about the
> +         * start of a new time slice.
> +         */
> +        if (rng->quota_remaining == 0) {
> +            pthread_cond_wait(&rng->rng_cond, &rng->rng_mutex);
> +        }
> +
> +        /* Start the timer if the last time slice has expired */
> +        if (rng->activate_timer == true) {
> +            rng->activate_timer = false;
> +            ret = timer_settime(rng->rate_limit_timer, 0, &rng->ts, NULL);
> +            if (ret < 0) {
> +                fprintf(stderr, "timer_settime() failed\n");
> +            }
> +        }
> +
> +        /* Make sure we don't read more than it's available */
> +        if (rng->quota_remaining < to_read) {
> +            to_read = rng->quota_remaining;
> +        }
> +
> +        len = read(source_fd, elem->in_sg[0].iov_base, to_read);
> +
> +        /* Simply return 0 if an error occurs */
> +        if (len < 0) {
> +            len = 0;
> +        }
> +
> +        rng->quota_remaining -= len;
> +
> +        pthread_mutex_unlock(&rng->rng_mutex);
> +
> +        vu_queue_push(dev, vq, elem, len);
> +        free(elem);
> +    }
> +
> +    vu_queue_notify(dev, vq);
> +}
> +
> +static void
> +vu_rng_queue_set_started(VuDev *dev, int qidx, bool started)
> +{
> +    VuVirtq *vq = vu_get_queue(dev, qidx);
> +
> +    g_debug("queue started %d:%d\n", qidx, started);
> +
> +    if (!qidx) {
> +        vu_set_queue_handler(dev, vq, started ? vu_rng_handle_requests : NULL);
> +    }
> +}
> +
> +/*
> + * Any messages not handled here are processed by the libvhost library
> + * itself.
> + */
> +static int rng_process_msg(VuDev *dev, VhostUserMsg *msg, int *do_reply)
> +{
> +    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
> +
> +    if (msg->request == VHOST_USER_NONE) {
> +        g_main_loop_quit(rng->loop);
> +        return 1;
> +    }
> +
> +    return 0;
> +}
> +
> +static const VuDevIface vuiface = {
> +    .set_features = rng_set_features,
> +    .get_features = rng_get_features,
> +    .queue_set_started = vu_rng_queue_set_started,
> +    .process_msg = rng_process_msg,
> +};
> +
> +static gboolean hangup(gpointer user_data)
> +{
> +    GMainLoop *loop = (GMainLoop *) user_data;
> +
> +    g_printerr("%s: caught hangup/quit signal, quitting", __func__);
> +    g_main_loop_quit(loop);
> +    return true;
> +}
> +
> +static void panic(VuDev *dev, const char *msg)
> +{
> +    g_critical("%s\n", msg);
> +    exit(EXIT_FAILURE);
> +}
> +
> +/* Print vhost-user.json backend program capabilities */
> +static void print_capabilities(void)
> +{
> +    printf("{\n");
> +    printf("  \"type\": \"RNG\"\n");
> +    printf("  \"filename\": [ RNG source ]\n");
> +    printf("}\n");
> +}
> +
> +static GOptionEntry options[] = {
> +    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &socket_path,
> +      "Location of vhost-user Unix domain socket, incompatible with --fd",
> +      "PATH" },
> +    { "fd", 'f', 0, G_OPTION_ARG_INT, &socket_fd,
> +      "Specify the backend file-descriptor, incompatible with --socket-path",
> +      "FD" },
> +    { "period", 'p', 0, G_OPTION_ARG_INT, &period_ms,
> +      "Time needed (in ms) to transfer a maximum amount of byte", NULL },
> +    { "max-bytes", 'm', 0, G_OPTION_ARG_INT64, &max_bytes,
> +      "Maximum amount of byte that can be transferred in a period", NULL },
> +    { "filename", 'n', 0, G_OPTION_ARG_FILENAME, &source_path,
> +      "RNG source, defaults to /dev/urandom", "PATH" },
> +    { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &print_cap,
> +      "Output to stdout the backend capabilities in JSON format and exit",
> +      NULL},
> +    { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose,
> +      "Be more verbose in output", NULL},
> +    { NULL }
> +};
> +
> +int main(int argc, char *argv[])
> +{
> +    GError *error = NULL;
> +    GOptionContext *context;
> +    g_autoptr(GSocket) socket = NULL;
> +    char default_source[] = "/dev/urandom";
> +    char *source = default_source;
> +    VuRNG rng;
> +
> +    context = g_option_context_new("vhost-user emulation of RNG device");
> +    g_option_context_add_main_entries(context, options, "vhost-user-rng");
> +    if (!g_option_context_parse(context, &argc, &argv, &error)) {
> +        g_printerr("option parsing failed: %s\n", error->message);
> +        exit(1);
> +    }
> +
> +    if (print_cap) {
> +        print_capabilities();
> +        exit(0);
> +    }
> +
> +    if (!socket_path && socket_fd < 0) {
> +        g_printerr("Please specify either --fd or --socket-path\n");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    if (socket_path && socket_fd > 0) {
> +        g_printerr("Either --fd or --socket-path, not both\n");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    if (max_bytes > INT64_MAX) {
> +        g_printerr("'max-bytes' parameter must be non-negative, "
> +                   "and less than 2^63\n");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    if (period_ms <= 0) {
> +        g_printerr("'period' parameter expects a positive integer\n");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    /*
> +     * Now create a vhost-user socket that we will receive messages
> +     * on. Once we have our handler set up we can enter the glib main
> +     * loop.
> +     */
> +    if (socket_path) {
> +        g_autoptr(GSocketAddress) addr = g_unix_socket_address_new(socket_path);
> +        g_autoptr(GSocket) bind_socket = g_socket_new(G_SOCKET_FAMILY_UNIX,
> +                                                      G_SOCKET_TYPE_STREAM,
> +                                                      G_SOCKET_PROTOCOL_DEFAULT,
> +                                                      &error);
> +
> +        if (!g_socket_bind(bind_socket, addr, false, &error)) {
> +            g_printerr("Failed to bind to socket at %s (%s).\n",
> +                       socket_path, error->message);
> +            exit(EXIT_FAILURE);
> +        }
> +        if (!g_socket_listen(bind_socket, &error)) {
> +            g_printerr("Failed to listen on socket %s (%s).\n",
> +                       socket_path, error->message);
> +        }
> +        g_message("awaiting connection to %s", socket_path);
> +        socket = g_socket_accept(bind_socket, NULL, &error);
> +        if (!socket) {
> +            g_printerr("Failed to accept on socket %s (%s).\n",
> +                       socket_path, error->message);
> +        }
> +    } else {
> +        socket = g_socket_new_from_fd(socket_fd, &error);
> +        if (!socket) {
> +            g_printerr("Failed to connect to FD %d (%s).\n",
> +                       socket_fd, error->message);
> +            exit(EXIT_FAILURE);
> +        }
> +    }
> +
> +    /* Overwrite default RNG source with what user provided, if any */
> +    if (source_path) {
> +        source = source_path;
> +    }
> +
> +    source_fd = open(source, O_RDWR);
> +    if (source_fd < 0) {
> +        g_printerr("Failed to open RNG source %s\n", source);
> +        g_socket_close(socket, &error);
> +        unlink(socket_path);
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    /* catch exit signals */
> +    g_unix_signal_add(SIGHUP, hangup, rng.loop);
> +    g_unix_signal_add(SIGINT, hangup, rng.loop);
> +
> +    /*
> +     * Create the main loop first so all the various sources can be
> +     * added. As well as catching signals we need to ensure vug_init
> +     * can add it's GSource watches.
> +     */
> +    rng.loop = g_main_loop_new(NULL, FALSE);
> +
> +    if (!vug_init(&rng.dev, 1, g_socket_get_fd(socket),
> +                  panic, &vuiface)) {
> +        g_printerr("Failed to initialize libvhost-user-glib.\n");
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    rng.quota_remaining = max_bytes;
> +    rng.activate_timer = true;
> +    pthread_mutex_init(&rng.rng_mutex, NULL);
> +    pthread_cond_init(&rng.rng_cond, NULL);
> +    setup_timer(&rng);
> +
> +    if (verbose) {
> +        g_info("period_ms: %d tv_sec: %ld tv_nsec: %lu\n",
> +               period_ms, rng.ts.it_value.tv_sec, rng.ts.it_value.tv_nsec);
> +    }
> +
> +    g_message("entering main loop, awaiting messages");
> +    g_main_loop_run(rng.loop);
> +    g_message("finished main loop, cleaning up");
> +
> +    g_main_loop_unref(rng.loop);
> +    vug_deinit(&rng.dev);
> +    timer_delete(rng.rate_limit_timer);
> +    close(source_fd);
> +    unlink(socket_path);
> +}
> diff --git a/tools/vhost-user-rng/meson.build b/tools/vhost-user-rng/meson.build
> new file mode 100644
> index 000000000000..4dc386daf335
> --- /dev/null
> +++ b/tools/vhost-user-rng/meson.build
> @@ -0,0 +1,10 @@
> +executable('vhost-user-rng', files(
> +  'main.c'),
> +  dependencies: [qemuutil, glib, gio, rt],
> +  install: true,
> +  install_dir: get_option('libexecdir'))
> +
> +configure_file(input: '50-qemu-rng.json.in',
> +               output: '50-qemu-rng.json',
> +               configuration: config_host,
> +               install_dir: qemu_datadir / 'vhost-user')
> -- 
> 2.25.1
> 
> -- 
> Stratos-dev mailing list
> Stratos-dev@op-lists.linaro.org
> https://op-lists.linaro.org/mailman/listinfo/stratos-dev

Re: [Stratos-dev] [PATCH 3/5] vhost-user-rng: backend: Add RNG vhost-user daemon implementation

[Mathieu Poirier]

On Tue, 1 Jun 2021 at 15:01, Joakim Bech <joakim.bech@linaro.org> wrote:
>
> On Tue, Jun 01, 2021 at 08:03:20PM +0000, Mathieu Poirier via Stratos-dev wrote:
> > This patch provides the vhost-user backend implementation to work
> > in tandem with the vhost-user-rng implementation of the QEMU VMM.
> >
> > It uses the vhost-user API so that other VMM can re-use the interface
> > without having to write the driver again.
> >
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > ---
> >  tools/meson.build                        |   8 +
> >  tools/vhost-user-rng/50-qemu-rng.json.in |   5 +
> >  tools/vhost-user-rng/main.c              | 403 +++++++++++++++++++++++
> >  tools/vhost-user-rng/meson.build         |  10 +
> >  4 files changed, 426 insertions(+)
> >  create mode 100644 tools/vhost-user-rng/50-qemu-rng.json.in
> >  create mode 100644 tools/vhost-user-rng/main.c
> >  create mode 100644 tools/vhost-user-rng/meson.build
> >
> > diff --git a/tools/meson.build b/tools/meson.build
> > index 3e5a0abfa29f..66b0a11fbb45 100644
> > --- a/tools/meson.build
> > +++ b/tools/meson.build
> > @@ -24,3 +24,11 @@ endif
> >  if have_virtiofsd
> >    subdir('virtiofsd')
> >  endif
> > +
> > +have_virtiorng = (have_system and
> > +    have_tools and
> > +    'CONFIG_LINUX' in config_host)
> > +
> > +if have_virtiorng
> > +  subdir('vhost-user-rng')
> > +endif
> > diff --git a/tools/vhost-user-rng/50-qemu-rng.json.in b/tools/vhost-user-rng/50-qemu-rng.json.in
> > new file mode 100644
> > index 000000000000..9186c3c6fe1d
> > --- /dev/null
> > +++ b/tools/vhost-user-rng/50-qemu-rng.json.in
> > @@ -0,0 +1,5 @@
> > +{
> > +  "description": "QEMU vhost-user-rng",
> > +  "type": "bridge",
> > +  "binary": "@libexecdir@/vhost-user-rng"
> > +}
> > diff --git a/tools/vhost-user-rng/main.c b/tools/vhost-user-rng/main.c
> > new file mode 100644
> > index 000000000000..ba7380b12659
> > --- /dev/null
> > +++ b/tools/vhost-user-rng/main.c
> > @@ -0,0 +1,403 @@
> > +/*
> > + * VIRTIO RNG Emulation via vhost-user
> > + *
> > + * Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
> > + *
> > + * SPDX-License-Identifier: GPL-2.0-or-later
> > + */
> > +
> > +#define G_LOG_DOMAIN "vhost-user-rng"
> > +#define G_LOG_USE_STRUCTURED 1
> > +
> > +#include <glib.h>
> > +#include <gio/gio.h>
> > +#include <gio/gunixsocketaddress.h>
> > +#include <glib-unix.h>
> > +#include <glib/gstdio.h>
> > +#include <pthread.h>
> > +#include <signal.h>
> > +#include <stdio.h>
> > +#include <stdbool.h>
> > +#include <string.h>
> > +#include <inttypes.h>
> > +#include <fcntl.h>
> > +#include <sys/ioctl.h>
> > +#include <sys/types.h>
> > +#include <sys/stat.h>
> > +#include <sys/mman.h>
> > +#include <time.h>
> > +#include <unistd.h>
> > +#include <endian.h>
> > +#include <assert.h>
> > +
> > +#include "qemu/cutils.h"
> > +#include "subprojects/libvhost-user/libvhost-user-glib.h"
> > +#include "subprojects/libvhost-user/libvhost-user.h"
> > +
> > +#ifndef container_of
> > +#define container_of(ptr, type, member) ({                      \
> > +        const typeof(((type *) 0)->member) * __mptr = (ptr);     \
> > +        (type *) ((char *) __mptr - offsetof(type, member)); })
> > +#endif
> > +
> > +typedef struct {
> > +    VugDev dev;
> > +    struct itimerspec ts;
> > +    timer_t rate_limit_timer;
> > +    pthread_mutex_t rng_mutex;
> > +    pthread_cond_t rng_cond;
> > +    int64_t quota_remaining;
> > +    bool activate_timer;
> > +    GMainLoop *loop;
> > +} VuRNG;
> > +
> > +static gboolean print_cap, verbose;
> > +static gchar *source_path, *socket_path;
> > +static gint source_fd, socket_fd = -1;
> > +
> > +/* Defaults tailored on virtio-rng.c */
> > +static uint32_t period_ms = 1 << 16;
> > +static uint64_t max_bytes = INT64_MAX;
> > +
> > +static void check_rate_limit(union sigval sv)
> > +{
> > +    VuRNG *rng = sv.sival_ptr;
> > +    bool wakeup = false;
> > +
> > +    pthread_mutex_lock(&rng->rng_mutex);
> > +    /*
> > +     * The timer has expired and the guest has used all available
> > +     * antropy, which means function vu_rng_handle_request() is waiting
> s/antropy/entropy/
>
> I also found 'antropy' at two more locations in this patch (that made me
> wonder).
>

Thanks for pointing that out, will fix for the next revision.

Mathieu

> > +     * on us.  As such wake it up once we're done here.
> > +     */
> > +    if (rng->quota_remaining == 0) {
> > +        wakeup = true;
> > +    }
> > +
> > +    /*
> > +     * Reset the antropy available to the guest and tell function
> > +     * vu_rng_handle_requests() to start the timer before using it.
> > +     */
> > +    rng->quota_remaining = max_bytes;
> > +    rng->activate_timer = true;
> > +    pthread_mutex_unlock(&rng->rng_mutex);
> > +
> > +    if (wakeup) {
> > +        pthread_cond_signal(&rng->rng_cond);
> > +    }
> > +}
> > +
> > +static void setup_timer(VuRNG *rng)
> > +{
> > +    struct sigevent sev;
> > +    int ret;
> > +
> > +    memset(&rng->ts, 0, sizeof(struct itimerspec));
> > +    rng->ts.it_value.tv_sec = period_ms / 1000;
> > +    rng->ts.it_value.tv_nsec = (period_ms % 1000) * 1000000;
> > +
> > +    /*
> > +     * Call function check_rate_limit() as if it was the start of
> > +     * a new thread when the timer expires.
> > +     */
> > +    sev.sigev_notify = SIGEV_THREAD;
> > +    sev.sigev_notify_function = check_rate_limit;
> > +    sev.sigev_value.sival_ptr = rng;
> > +    /* Needs to be NULL if defaults attributes are to be used. */
> > +    sev.sigev_notify_attributes = NULL;
> > +    ret = timer_create(CLOCK_MONOTONIC, &sev, &rng->rate_limit_timer);
> > +    if (ret < 0) {
> > +        fprintf(stderr, "timer_create() failed\n");
> > +    }
> > +
> > +}
> > +
> > +
> > +/* Virtio helpers */
> > +static uint64_t rng_get_features(VuDev *dev)
> > +{
> > +    if (verbose) {
> > +        g_info("%s: replying", __func__);
> > +    }
> > +    return 0;
> > +}
> > +
> > +static void rng_set_features(VuDev *dev, uint64_t features)
> > +{
> > +    if (verbose && features) {
> > +        g_autoptr(GString) s = g_string_new("Requested un-handled feature");
> > +        g_string_append_printf(s, " 0x%" PRIx64 "", features);
> > +        g_info("%s: %s", __func__, s->str);
> > +    }
> > +}
> > +
> > +static void vu_rng_handle_requests(VuDev *dev, int qidx)
> > +{
> > +    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
> > +    VuVirtq *vq = vu_get_queue(dev, qidx);
> > +    VuVirtqElement *elem;
> > +    size_t to_read;
> > +    int len, ret;
> > +
> > +    for (;;) {
> > +        /* Get element in the vhost virtqueue */
> > +        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
> > +        if (!elem) {
> > +            break;
> > +        }
> > +
> > +        /* Get the amount of antropy to read from the vhost server */
> > +        to_read = elem->in_sg[0].iov_len;
> > +
> > +        pthread_mutex_lock(&rng->rng_mutex);
> > +
> > +        /*
> > +         * We have consumed all entropy available for this time slice.
> > +         * Wait for the timer (check_rate_limit()) to tell us about the
> > +         * start of a new time slice.
> > +         */
> > +        if (rng->quota_remaining == 0) {
> > +            pthread_cond_wait(&rng->rng_cond, &rng->rng_mutex);
> > +        }
> > +
> > +        /* Start the timer if the last time slice has expired */
> > +        if (rng->activate_timer == true) {
> > +            rng->activate_timer = false;
> > +            ret = timer_settime(rng->rate_limit_timer, 0, &rng->ts, NULL);
> > +            if (ret < 0) {
> > +                fprintf(stderr, "timer_settime() failed\n");
> > +            }
> > +        }
> > +
> > +        /* Make sure we don't read more than it's available */
> > +        if (rng->quota_remaining < to_read) {
> > +            to_read = rng->quota_remaining;
> > +        }
> > +
> > +        len = read(source_fd, elem->in_sg[0].iov_base, to_read);
> > +
> > +        /* Simply return 0 if an error occurs */
> > +        if (len < 0) {
> > +            len = 0;
> > +        }
> > +
> > +        rng->quota_remaining -= len;
> > +
> > +        pthread_mutex_unlock(&rng->rng_mutex);
> > +
> > +        vu_queue_push(dev, vq, elem, len);
> > +        free(elem);
> > +    }
> > +
> > +    vu_queue_notify(dev, vq);
> > +}
> > +
> > +static void
> > +vu_rng_queue_set_started(VuDev *dev, int qidx, bool started)
> > +{
> > +    VuVirtq *vq = vu_get_queue(dev, qidx);
> > +
> > +    g_debug("queue started %d:%d\n", qidx, started);
> > +
> > +    if (!qidx) {
> > +        vu_set_queue_handler(dev, vq, started ? vu_rng_handle_requests : NULL);
> > +    }
> > +}
> > +
> > +/*
> > + * Any messages not handled here are processed by the libvhost library
> > + * itself.
> > + */
> > +static int rng_process_msg(VuDev *dev, VhostUserMsg *msg, int *do_reply)
> > +{
> > +    VuRNG *rng = container_of(dev, VuRNG, dev.parent);
> > +
> > +    if (msg->request == VHOST_USER_NONE) {
> > +        g_main_loop_quit(rng->loop);
> > +        return 1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static const VuDevIface vuiface = {
> > +    .set_features = rng_set_features,
> > +    .get_features = rng_get_features,
> > +    .queue_set_started = vu_rng_queue_set_started,
> > +    .process_msg = rng_process_msg,
> > +};
> > +
> > +static gboolean hangup(gpointer user_data)
> > +{
> > +    GMainLoop *loop = (GMainLoop *) user_data;
> > +
> > +    g_printerr("%s: caught hangup/quit signal, quitting", __func__);
> > +    g_main_loop_quit(loop);
> > +    return true;
> > +}
> > +
> > +static void panic(VuDev *dev, const char *msg)
> > +{
> > +    g_critical("%s\n", msg);
> > +    exit(EXIT_FAILURE);
> > +}
> > +
> > +/* Print vhost-user.json backend program capabilities */
> > +static void print_capabilities(void)
> > +{
> > +    printf("{\n");
> > +    printf("  \"type\": \"RNG\"\n");
> > +    printf("  \"filename\": [ RNG source ]\n");
> > +    printf("}\n");
> > +}
> > +
> > +static GOptionEntry options[] = {
> > +    { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &socket_path,
> > +      "Location of vhost-user Unix domain socket, incompatible with --fd",
> > +      "PATH" },
> > +    { "fd", 'f', 0, G_OPTION_ARG_INT, &socket_fd,
> > +      "Specify the backend file-descriptor, incompatible with --socket-path",
> > +      "FD" },
> > +    { "period", 'p', 0, G_OPTION_ARG_INT, &period_ms,
> > +      "Time needed (in ms) to transfer a maximum amount of byte", NULL },
> > +    { "max-bytes", 'm', 0, G_OPTION_ARG_INT64, &max_bytes,
> > +      "Maximum amount of byte that can be transferred in a period", NULL },
> > +    { "filename", 'n', 0, G_OPTION_ARG_FILENAME, &source_path,
> > +      "RNG source, defaults to /dev/urandom", "PATH" },
> > +    { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &print_cap,
> > +      "Output to stdout the backend capabilities in JSON format and exit",
> > +      NULL},
> > +    { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose,
> > +      "Be more verbose in output", NULL},
> > +    { NULL }
> > +};
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +    GError *error = NULL;
> > +    GOptionContext *context;
> > +    g_autoptr(GSocket) socket = NULL;
> > +    char default_source[] = "/dev/urandom";
> > +    char *source = default_source;
> > +    VuRNG rng;
> > +
> > +    context = g_option_context_new("vhost-user emulation of RNG device");
> > +    g_option_context_add_main_entries(context, options, "vhost-user-rng");
> > +    if (!g_option_context_parse(context, &argc, &argv, &error)) {
> > +        g_printerr("option parsing failed: %s\n", error->message);
> > +        exit(1);
> > +    }
> > +
> > +    if (print_cap) {
> > +        print_capabilities();
> > +        exit(0);
> > +    }
> > +
> > +    if (!socket_path && socket_fd < 0) {
> > +        g_printerr("Please specify either --fd or --socket-path\n");
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    if (socket_path && socket_fd > 0) {
> > +        g_printerr("Either --fd or --socket-path, not both\n");
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    if (max_bytes > INT64_MAX) {
> > +        g_printerr("'max-bytes' parameter must be non-negative, "
> > +                   "and less than 2^63\n");
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    if (period_ms <= 0) {
> > +        g_printerr("'period' parameter expects a positive integer\n");
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    /*
> > +     * Now create a vhost-user socket that we will receive messages
> > +     * on. Once we have our handler set up we can enter the glib main
> > +     * loop.
> > +     */
> > +    if (socket_path) {
> > +        g_autoptr(GSocketAddress) addr = g_unix_socket_address_new(socket_path);
> > +        g_autoptr(GSocket) bind_socket = g_socket_new(G_SOCKET_FAMILY_UNIX,
> > +                                                      G_SOCKET_TYPE_STREAM,
> > +                                                      G_SOCKET_PROTOCOL_DEFAULT,
> > +                                                      &error);
> > +
> > +        if (!g_socket_bind(bind_socket, addr, false, &error)) {
> > +            g_printerr("Failed to bind to socket at %s (%s).\n",
> > +                       socket_path, error->message);
> > +            exit(EXIT_FAILURE);
> > +        }
> > +        if (!g_socket_listen(bind_socket, &error)) {
> > +            g_printerr("Failed to listen on socket %s (%s).\n",
> > +                       socket_path, error->message);
> > +        }
> > +        g_message("awaiting connection to %s", socket_path);
> > +        socket = g_socket_accept(bind_socket, NULL, &error);
> > +        if (!socket) {
> > +            g_printerr("Failed to accept on socket %s (%s).\n",
> > +                       socket_path, error->message);
> > +        }
> > +    } else {
> > +        socket = g_socket_new_from_fd(socket_fd, &error);
> > +        if (!socket) {
> > +            g_printerr("Failed to connect to FD %d (%s).\n",
> > +                       socket_fd, error->message);
> > +            exit(EXIT_FAILURE);
> > +        }
> > +    }
> > +
> > +    /* Overwrite default RNG source with what user provided, if any */
> > +    if (source_path) {
> > +        source = source_path;
> > +    }
> > +
> > +    source_fd = open(source, O_RDWR);
> > +    if (source_fd < 0) {
> > +        g_printerr("Failed to open RNG source %s\n", source);
> > +        g_socket_close(socket, &error);
> > +        unlink(socket_path);
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    /* catch exit signals */
> > +    g_unix_signal_add(SIGHUP, hangup, rng.loop);
> > +    g_unix_signal_add(SIGINT, hangup, rng.loop);
> > +
> > +    /*
> > +     * Create the main loop first so all the various sources can be
> > +     * added. As well as catching signals we need to ensure vug_init
> > +     * can add it's GSource watches.
> > +     */
> > +    rng.loop = g_main_loop_new(NULL, FALSE);
> > +
> > +    if (!vug_init(&rng.dev, 1, g_socket_get_fd(socket),
> > +                  panic, &vuiface)) {
> > +        g_printerr("Failed to initialize libvhost-user-glib.\n");
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    rng.quota_remaining = max_bytes;
> > +    rng.activate_timer = true;
> > +    pthread_mutex_init(&rng.rng_mutex, NULL);
> > +    pthread_cond_init(&rng.rng_cond, NULL);
> > +    setup_timer(&rng);
> > +
> > +    if (verbose) {
> > +        g_info("period_ms: %d tv_sec: %ld tv_nsec: %lu\n",
> > +               period_ms, rng.ts.it_value.tv_sec, rng.ts.it_value.tv_nsec);
> > +    }
> > +
> > +    g_message("entering main loop, awaiting messages");
> > +    g_main_loop_run(rng.loop);
> > +    g_message("finished main loop, cleaning up");
> > +
> > +    g_main_loop_unref(rng.loop);
> > +    vug_deinit(&rng.dev);
> > +    timer_delete(rng.rate_limit_timer);
> > +    close(source_fd);
> > +    unlink(socket_path);
> > +}
> > diff --git a/tools/vhost-user-rng/meson.build b/tools/vhost-user-rng/meson.build
> > new file mode 100644
> > index 000000000000..4dc386daf335
> > --- /dev/null
> > +++ b/tools/vhost-user-rng/meson.build
> > @@ -0,0 +1,10 @@
> > +executable('vhost-user-rng', files(
> > +  'main.c'),
> > +  dependencies: [qemuutil, glib, gio, rt],
> > +  install: true,
> > +  install_dir: get_option('libexecdir'))
> > +
> > +configure_file(input: '50-qemu-rng.json.in',
> > +               output: '50-qemu-rng.json',
> > +               configuration: config_host,
> > +               install_dir: qemu_datadir / 'vhost-user')
> > --
> > 2.25.1
> >
> > --
> > Stratos-dev mailing list
> > Stratos-dev@op-lists.linaro.org
> > https://op-lists.linaro.org/mailman/listinfo/stratos-dev