Initial import of qemu-2.4.1HEADmaster

1 files changed, 267 insertions, 0 deletions

diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
new file mode 100644
index 00000000..97d15419
--- /dev/null
+++ b/hw/virtio/virtio-rng.c
@@ -0,0 +1,267 @@
+/*
+ * A virtio device implementing a hardware random number generator.
+ *
+ * Copyright 2012 Red Hat, Inc.
+ * Copyright 2012 Amit Shah <amit.shah@redhat.com>
+ *
+ * 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/iov.h"
+#include "hw/qdev.h"
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-rng.h"
+#include "sysemu/rng.h"
+#include "qom/object_interfaces.h"
+#include "trace.h"
+
+static bool is_guest_ready(VirtIORNG *vrng)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
+    if (virtio_queue_ready(vrng->vq)
+        && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+        return true;
+    }
+    trace_virtio_rng_guest_not_ready(vrng);
+    return false;
+}
+
+static size_t get_request_size(VirtQueue *vq, unsigned quota)
+{
+    unsigned int in, out;
+
+    virtqueue_get_avail_bytes(vq, &in, &out, quota, 0);
+    return in;
+}
+
+static void virtio_rng_process(VirtIORNG *vrng);
+
+/* Send data from a char device over to the guest */
+static void chr_read(void *opaque, const void *buf, size_t size)
+{
+    VirtIORNG *vrng = opaque;
+    VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
+    VirtQueueElement elem;
+    size_t len;
+    int offset;
+
+    if (!is_guest_ready(vrng)) {
+        return;
+    }
+
+    vrng->quota_remaining -= size;
+
+    offset = 0;
+    while (offset < size) {
+        if (!virtqueue_pop(vrng->vq, &elem)) {
+            break;
+        }
+        len = iov_from_buf(elem.in_sg, elem.in_num,
+                           0, buf + offset, size - offset);
+        offset += len;
+
+        virtqueue_push(vrng->vq, &elem, len);
+        trace_virtio_rng_pushed(vrng, len);
+    }
+    virtio_notify(vdev, vrng->vq);
+}
+
+static void virtio_rng_process(VirtIORNG *vrng)
+{
+    size_t size;
+    unsigned quota;
+
+    if (!is_guest_ready(vrng)) {
+        return;
+    }
+
+    if (vrng->activate_timer) {
+        timer_mod(vrng->rate_limit_timer,
+                  qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms);
+        vrng->activate_timer = false;
+    }
+
+    if (vrng->quota_remaining < 0) {
+        quota = 0;
+    } else {
+        quota = MIN((uint64_t)vrng->quota_remaining, (uint64_t)UINT32_MAX);
+    }
+    size = get_request_size(vrng->vq, quota);
+
+    trace_virtio_rng_request(vrng, size, quota);
+
+    size = MIN(vrng->quota_remaining, size);
+    if (size) {
+        rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
+    }
+}
+
+static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIORNG *vrng = VIRTIO_RNG(vdev);
+    virtio_rng_process(vrng);
+}
+
+static uint64_t get_features(VirtIODevice *vdev, uint64_t f, Error **errp)
+{
+    return f;
+}
+
+static void virtio_rng_save(QEMUFile *f, void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+
+    virtio_save(vdev, f);
+}
+
+static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIORNG *vrng = opaque;
+    int ret;
+
+    if (version_id != 1) {
+        return -EINVAL;
+    }
+    ret = virtio_load(VIRTIO_DEVICE(vrng), f, version_id);
+    if (ret != 0) {
+        return ret;
+    }
+
+    /* We may have an element ready but couldn't process it due to a quota
+     * limit.  Make sure to try again after live migration when the quota may
+     * have been reset.
+     */
+    virtio_rng_process(vrng);
+
+    return 0;
+}
+
+static void check_rate_limit(void *opaque)
+{
+    VirtIORNG *vrng = opaque;
+
+    vrng->quota_remaining = vrng->conf.max_bytes;
+    virtio_rng_process(vrng);
+    vrng->activate_timer = true;
+}
+
+static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIORNG *vrng = VIRTIO_RNG(dev);
+    Error *local_err = NULL;
+
+    if (vrng->conf.period_ms <= 0) {
+        error_setg(errp, "'period' parameter expects a positive integer");
+        return;
+    }
+
+    /* Workaround: Property parsing does not enforce unsigned integers,
+     * So this is a hack to reject such numbers. */
+    if (vrng->conf.max_bytes > INT64_MAX) {
+        error_setg(errp, "'max-bytes' parameter must be non-negative, "
+                   "and less than 2^63");
+        return;
+    }
+
+    if (vrng->conf.rng == NULL) {
+        vrng->conf.default_backend = RNG_RANDOM(object_new(TYPE_RNG_RANDOM));
+
+        user_creatable_complete(OBJECT(vrng->conf.default_backend),
+                                &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            object_unref(OBJECT(vrng->conf.default_backend));
+            return;
+        }
+
+        object_property_add_child(OBJECT(dev),
+                                  "default-backend",
+                                  OBJECT(vrng->conf.default_backend),
+                                  NULL);
+
+        /* The child property took a reference, we can safely drop ours now */
+        object_unref(OBJECT(vrng->conf.default_backend));
+
+        object_property_set_link(OBJECT(dev),
+                                 OBJECT(vrng->conf.default_backend),
+                                 "rng", NULL);
+    }
+
+    vrng->rng = vrng->conf.rng;
+    if (vrng->rng == NULL) {
+        error_setg(errp, "'rng' parameter expects a valid object");
+        return;
+    }
+
+    virtio_init(vdev, "virtio-rng", VIRTIO_ID_RNG, 0);
+
+    vrng->vq = virtio_add_queue(vdev, 8, handle_input);
+    vrng->quota_remaining = vrng->conf.max_bytes;
+    vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
+                                               check_rate_limit, vrng);
+    vrng->activate_timer = true;
+    register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
+                    virtio_rng_load, vrng);
+}
+
+static void virtio_rng_device_unrealize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIORNG *vrng = VIRTIO_RNG(dev);
+
+    timer_del(vrng->rate_limit_timer);
+    timer_free(vrng->rate_limit_timer);
+    unregister_savevm(dev, "virtio-rng", vrng);
+    virtio_cleanup(vdev);
+}
+
+static Property virtio_rng_properties[] = {
+    /* Set a default rate limit of 2^47 bytes per minute or roughly 2TB/s.  If
+     * you have an entropy source capable of generating more entropy than this
+     * and you can pass it through via virtio-rng, then hats off to you.  Until
+     * then, this is unlimited for all practical purposes.
+     */
+    DEFINE_PROP_UINT64("max-bytes", VirtIORNG, conf.max_bytes, INT64_MAX),
+    DEFINE_PROP_UINT32("period", VirtIORNG, conf.period_ms, 1 << 16),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_rng_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    dc->props = virtio_rng_properties;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    vdc->realize = virtio_rng_device_realize;
+    vdc->unrealize = virtio_rng_device_unrealize;
+    vdc->get_features = get_features;
+}
+
+static void virtio_rng_initfn(Object *obj)
+{
+    VirtIORNG *vrng = VIRTIO_RNG(obj);
+
+    object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
+                             (Object **)&vrng->conf.rng,
+                             qdev_prop_allow_set_link_before_realize,
+                             OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
+}
+
+static const TypeInfo virtio_rng_info = {
+    .name = TYPE_VIRTIO_RNG,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VirtIORNG),
+    .instance_init = virtio_rng_initfn,
+    .class_init = virtio_rng_class_init,
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_rng_info);
+}
+
+type_init(virtio_register_types)