Add support for the virtio RNG entropy-source device.

Call through to /dev/random synchronously to fill
virtio buffers with RNG data.

Tested with FreeBSD-CURRENT and Ubuntu guests.

Submitted by:	Leon Dang
Discussed with:	markm
MFC after:	3 weeks
Sponsored by:	Nahanni Systems

usr.sbin/bhyve/Makefile

@@ -26,6 +26,7 @@ SRCS=	\
 	pci_passthru.c		\
 	pci_virtio_block.c	\
 	pci_virtio_net.c	\
+	pci_virtio_rnd.c	\
 	pci_uart.c		\
 	pm.c			\
 	pmtmr.c			\

usr.sbin/bhyve/bhyve.8

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 27, 2014
+.Dd April 2, 2014
 .Dt BHYVE 8
 .Os
 .Sh NAME
@@ -129,6 +129,8 @@ PCI pass-through device.
 Virtio network interface.
 .It Li virtio-blk
 Virtio block storage interface.
+.It Li virtio-rnd
+Virtio RNG interface.
 .It Li ahci-cd
 AHCI controller attached to an ATAPI CD/DVD.
 .It Li ahci-hd

usr.sbin/bhyve/pci_virtio_rnd.c

@@ -0,0 +1,189 @@
+/*-
+ * Copyright (c) 2014 Nahanni Systems Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * virtio entropy device emulation.
+ * Randomness is sourced from /dev/random which does not block
+ * once it has been seeded at bootup.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/linker_set.h>
+#include <sys/uio.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <pthread.h>
+
+#include "bhyverun.h"
+#include "pci_emul.h"
+#include "virtio.h"
+
+#define VTRND_RINGSZ	64
+
+
+static int pci_vtrnd_debug;
+#define DPRINTF(params) if (pci_vtrnd_debug) printf params
+#define WPRINTF(params) printf params
+
+/*
+ * Per-device softc
+ */
+struct pci_vtrnd_softc {
+	struct virtio_softc vrsc_vs;
+	struct vqueue_info  vrsc_vq;
+	pthread_mutex_t     vrsc_mtx;
+	uint64_t            vrsc_cfg;
+	int                 vrsc_fd;
+};
+
+static void pci_vtrnd_reset(void *);
+static void pci_vtrnd_notify(void *, struct vqueue_info *);
+
+static struct virtio_consts vtrnd_vi_consts = {
+	"vtrnd",		/* our name */
+	1,			/* we support 1 virtqueue */
+	0,			/* config reg size */
+	pci_vtrnd_reset,	/* reset */
+	pci_vtrnd_notify,	/* device-wide qnotify */
+	NULL,			/* read virtio config */
+	NULL,			/* write virtio config */
+	0,			/* our capabilities */
+};
+
+
+static void
+pci_vtrnd_reset(void *vsc)
+{
+	struct pci_vtrnd_softc *sc;
+
+	sc = vsc;
+
+	DPRINTF(("vtrnd: device reset requested !\n"));
+	vi_reset_dev(&sc->vrsc_vs);
+}
+
+
+static void
+pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
+{
+	struct iovec iov;
+	struct pci_vtrnd_softc *sc;
+	int len;
+
+	sc = vsc;
+
+	vq_startchains(vq);
+
+	if (sc->vrsc_fd < 0) {
+		vq_endchains(vq, 0);
+		return;
+	}
+
+	while (vq_has_descs(vq)) {
+		vq_getchain(vq, &iov, 1, NULL);
+
+		len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
+
+		DPRINTF(("vtrnd: vtrnd_notify(): %d\r\n", len));
+
+		/* Catastrophe if unable to read from /dev/random */
+		assert(len > 0);
+
+		/*
+		 * Release this chain and handle more
+		 */
+		vq_relchain(vq, len);
+	}
+	vq_endchains(vq, 1);	/* Generate interrupt if appropriate. */
+}
+
+
+static int
+pci_vtrnd_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
+{
+	struct pci_vtrnd_softc *sc;
+	int fd;
+	int len;
+	uint8_t v;
+
+	/*
+	 * Should always be able to open /dev/random.
+	 */
+	fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
+
+	assert(fd >= 0);
+
+	/*
+	 * Check that device is seeded and non-blocking.
+	 */
+	len = read(fd, &v, sizeof(v));
+	if (len <= 0) {
+		WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len));
+		return (1);
+	}
+
+	sc = malloc(sizeof(struct pci_vtrnd_softc));
+	memset(sc, 0, sizeof(struct pci_vtrnd_softc));
+
+	vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
+	sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
+
+	sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
+
+	/* keep /dev/random opened while emulating */
+	sc->vrsc_fd = fd;
+
+	/* initialize config space */
+	pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
+	pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
+	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
+	pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_TYPE_ENTROPY);
+
+	if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
+		return (1);
+	vi_set_io_bar(&sc->vrsc_vs, 0);
+
+	return (0);
+}
+
+
+struct pci_devemu pci_de_vrnd = {
+	.pe_emu =	"virtio-rnd",
+	.pe_init =	pci_vtrnd_init,
+	.pe_barwrite =	vi_pci_write,
+	.pe_barread =	vi_pci_read
+};
+PCI_EMUL_SET(pci_de_vrnd);

usr.sbin/bhyve/virtio.h

@@ -209,6 +209,7 @@ struct vring_used {
 #define	VIRTIO_VENDOR		0x1AF4
 #define	VIRTIO_DEV_NET		0x1000
 #define	VIRTIO_DEV_BLOCK	0x1001
+#define	VIRTIO_DEV_RANDOM	0x1002
 
 /*
  * PCI config space constants.