633218ee46
Rather than have every device register itself for both virtio_pci and virtio_mmio, provide a VIRTIO_DRIVER_MODULE wrapper to declare both, merge VIRTIO_SIMPLE_PNPTABLE with VIRTIO_SIMPLE_PNPINFO and make the latter register for both buses. This also has the benefit of abstracting away the available transports and their names. Reviewed by: bryanv Differential Revision: https://reviews.freebsd.org/D28073
287 lines
6.7 KiB
C
287 lines
6.7 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2013, Bryan Venteicher <bryanv@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Driver for VirtIO entropy device. */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/sglist.h>
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#include <sys/random.h>
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#include <sys/stdatomic.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/bus.h>
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#include <dev/random/randomdev.h>
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#include <dev/random/random_harvestq.h>
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#include <dev/virtio/virtio.h>
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#include <dev/virtio/virtqueue.h>
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struct vtrnd_softc {
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device_t vtrnd_dev;
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uint64_t vtrnd_features;
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struct virtqueue *vtrnd_vq;
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};
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static int vtrnd_modevent(module_t, int, void *);
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static int vtrnd_probe(device_t);
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static int vtrnd_attach(device_t);
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static int vtrnd_detach(device_t);
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static int vtrnd_negotiate_features(struct vtrnd_softc *);
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static int vtrnd_setup_features(struct vtrnd_softc *);
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static int vtrnd_alloc_virtqueue(struct vtrnd_softc *);
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static int vtrnd_harvest(struct vtrnd_softc *, void *, size_t *);
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static unsigned vtrnd_read(void *, unsigned);
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#define VTRND_FEATURES 0
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static struct virtio_feature_desc vtrnd_feature_desc[] = {
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{ 0, NULL }
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};
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static struct random_source random_vtrnd = {
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.rs_ident = "VirtIO Entropy Adapter",
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.rs_source = RANDOM_PURE_VIRTIO,
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.rs_read = vtrnd_read,
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};
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/* Kludge for API limitations of random(4). */
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static _Atomic(struct vtrnd_softc *) g_vtrnd_softc;
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static device_method_t vtrnd_methods[] = {
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/* Device methods. */
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DEVMETHOD(device_probe, vtrnd_probe),
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DEVMETHOD(device_attach, vtrnd_attach),
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DEVMETHOD(device_detach, vtrnd_detach),
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DEVMETHOD_END
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};
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static driver_t vtrnd_driver = {
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"vtrnd",
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vtrnd_methods,
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sizeof(struct vtrnd_softc)
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};
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static devclass_t vtrnd_devclass;
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VIRTIO_DRIVER_MODULE(virtio_random, vtrnd_driver, vtrnd_devclass,
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vtrnd_modevent, 0);
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MODULE_VERSION(virtio_random, 1);
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MODULE_DEPEND(virtio_random, virtio, 1, 1, 1);
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MODULE_DEPEND(virtio_random, random_device, 1, 1, 1);
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VIRTIO_SIMPLE_PNPINFO(virtio_random, VIRTIO_ID_ENTROPY,
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"VirtIO Entropy Adapter");
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static int
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vtrnd_modevent(module_t mod, int type, void *unused)
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{
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int error;
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switch (type) {
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case MOD_LOAD:
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case MOD_QUIESCE:
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case MOD_UNLOAD:
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case MOD_SHUTDOWN:
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error = 0;
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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static int
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vtrnd_probe(device_t dev)
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{
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return (VIRTIO_SIMPLE_PROBE(dev, virtio_random));
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}
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static int
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vtrnd_attach(device_t dev)
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{
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struct vtrnd_softc *sc, *exp;
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int error;
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sc = device_get_softc(dev);
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sc->vtrnd_dev = dev;
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virtio_set_feature_desc(dev, vtrnd_feature_desc);
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error = vtrnd_setup_features(sc);
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if (error) {
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device_printf(dev, "cannot setup features\n");
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goto fail;
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}
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error = vtrnd_alloc_virtqueue(sc);
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if (error) {
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device_printf(dev, "cannot allocate virtqueue\n");
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goto fail;
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}
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exp = NULL;
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if (!atomic_compare_exchange_strong_explicit(&g_vtrnd_softc, &exp, sc,
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memory_order_release, memory_order_acquire)) {
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error = EEXIST;
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goto fail;
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}
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random_source_register(&random_vtrnd);
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fail:
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if (error)
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vtrnd_detach(dev);
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return (error);
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}
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static int
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vtrnd_detach(device_t dev)
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{
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struct vtrnd_softc *sc;
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sc = device_get_softc(dev);
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KASSERT(
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atomic_load_explicit(&g_vtrnd_softc, memory_order_acquire) == sc,
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("only one global instance at a time"));
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random_source_deregister(&random_vtrnd);
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atomic_store_explicit(&g_vtrnd_softc, NULL, memory_order_release);
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return (0);
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}
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static int
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vtrnd_negotiate_features(struct vtrnd_softc *sc)
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{
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device_t dev;
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uint64_t features;
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dev = sc->vtrnd_dev;
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features = VTRND_FEATURES;
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sc->vtrnd_features = virtio_negotiate_features(dev, features);
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return (virtio_finalize_features(dev));
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}
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static int
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vtrnd_setup_features(struct vtrnd_softc *sc)
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{
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int error;
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error = vtrnd_negotiate_features(sc);
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if (error)
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return (error);
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return (0);
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}
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static int
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vtrnd_alloc_virtqueue(struct vtrnd_softc *sc)
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{
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device_t dev;
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struct vq_alloc_info vq_info;
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dev = sc->vtrnd_dev;
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VQ_ALLOC_INFO_INIT(&vq_info, 0, NULL, sc, &sc->vtrnd_vq,
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"%s request", device_get_nameunit(dev));
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return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info));
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}
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static int
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vtrnd_harvest(struct vtrnd_softc *sc, void *buf, size_t *sz)
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{
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struct sglist_seg segs[1];
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struct sglist sg;
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struct virtqueue *vq;
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uint32_t value[HARVESTSIZE] __aligned(sizeof(uint32_t) * HARVESTSIZE);
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uint32_t rdlen;
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int error;
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_Static_assert(sizeof(value) < PAGE_SIZE, "sglist assumption");
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sglist_init(&sg, 1, segs);
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error = sglist_append(&sg, value, *sz);
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if (error != 0)
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panic("%s: sglist_append error=%d", __func__, error);
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vq = sc->vtrnd_vq;
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KASSERT(virtqueue_empty(vq), ("%s: non-empty queue", __func__));
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error = virtqueue_enqueue(vq, buf, &sg, 0, 1);
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if (error != 0)
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return (error);
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/*
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* Poll for the response, but the command is likely already
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* done when we return from the notify.
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*/
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virtqueue_notify(vq);
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virtqueue_poll(vq, &rdlen);
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if (rdlen > *sz)
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panic("%s: random device wrote %zu bytes beyond end of provided"
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" buffer %p:%zu", __func__, (size_t)rdlen - *sz,
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(void *)value, *sz);
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else if (rdlen == 0)
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return (EAGAIN);
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*sz = MIN(rdlen, *sz);
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memcpy(buf, value, *sz);
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explicit_bzero(value, *sz);
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return (0);
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}
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static unsigned
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vtrnd_read(void *buf, unsigned usz)
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{
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struct vtrnd_softc *sc;
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size_t sz;
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int error;
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sc = g_vtrnd_softc;
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if (sc == NULL)
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return (0);
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sz = usz;
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error = vtrnd_harvest(sc, buf, &sz);
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if (error != 0)
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return (0);
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return (sz);
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}
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