From f7f510ec195781c857ab76366a3e1c59e1caae42 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 30 May 2008 15:09:44 -0500 Subject: virtio: An entropy device, as suggested by hpa. Note that by itself, having a "hardware" random generator does very little: you should probably run "rngd" in your guest to feed this into the kernel entropy pool. Included: virtio_rng: dont use vmalloced addresses for virtio If virtio_rng is build as a module, random_data is an address in vmalloc space. As virtio expects guest real addresses, this can cause any kind of funny behaviour, so lets allocate random_data dynamically with kmalloc. Signed-off-by: Christian Borntraeger Signed-off-by: Rusty Russell --- drivers/char/hw_random/Kconfig | 9 +++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/virtio-rng.c | 155 ++++++++++++++++++++++++++++++++++++ 3 files changed, 165 insertions(+) create mode 100644 drivers/char/hw_random/virtio-rng.c (limited to 'drivers/char/hw_random') diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 8d6c2089d2a..efd0b4db7c8 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -112,3 +112,12 @@ config HW_RANDOM_PASEMI If unsure, say Y. +config HW_RANDOM_VIRTIO + tristate "VirtIO Random Number Generator support" + depends on HW_RANDOM && VIRTIO + ---help--- + This driver provides kernel-side support for the virtual Random Number + Generator hardware. + + To compile this driver as a module, choose M here: the + module will be called virtio-rng. If unsure, say N. diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index c8b7300e2fb..b4940ddbb35 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o +obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c new file mode 100644 index 00000000000..d0e563e4fc3 --- /dev/null +++ b/drivers/char/hw_random/virtio-rng.c @@ -0,0 +1,155 @@ +/* + * Randomness driver for virtio + * Copyright (C) 2007, 2008 Rusty Russell IBM Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include +#include +#include +#include +#include +#include + +/* The host will fill any buffer we give it with sweet, sweet randomness. We + * give it 64 bytes at a time, and the hwrng framework takes it 4 bytes at a + * time. */ +#define RANDOM_DATA_SIZE 64 + +static struct virtqueue *vq; +static u32 *random_data; +static unsigned int data_left; +static DECLARE_COMPLETION(have_data); + +static void random_recv_done(struct virtqueue *vq) +{ + int len; + + /* We never get spurious callbacks. */ + if (!vq->vq_ops->get_buf(vq, &len)) + BUG(); + + data_left = len / sizeof(random_data[0]); + complete(&have_data); +} + +static void register_buffer(void) +{ + struct scatterlist sg; + + sg_init_one(&sg, random_data, RANDOM_DATA_SIZE); + /* There should always be room for one buffer. */ + if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) != 0) + BUG(); + vq->vq_ops->kick(vq); +} + +/* At least we don't udelay() in a loop like some other drivers. */ +static int virtio_data_present(struct hwrng *rng, int wait) +{ + if (data_left) + return 1; + + if (!wait) + return 0; + + wait_for_completion(&have_data); + return 1; +} + +/* virtio_data_present() must have succeeded before this is called. */ +static int virtio_data_read(struct hwrng *rng, u32 *data) +{ + BUG_ON(!data_left); + + *data = random_data[--data_left]; + + if (!data_left) { + init_completion(&have_data); + register_buffer(); + } + return sizeof(*data); +} + +static struct hwrng virtio_hwrng = { + .name = "virtio", + .data_present = virtio_data_present, + .data_read = virtio_data_read, +}; + +static int virtrng_probe(struct virtio_device *vdev) +{ + int err; + + /* We expect a single virtqueue. */ + vq = vdev->config->find_vq(vdev, 0, random_recv_done); + if (IS_ERR(vq)) + return PTR_ERR(vq); + + err = hwrng_register(&virtio_hwrng); + if (err) { + vdev->config->del_vq(vq); + return err; + } + + register_buffer(); + return 0; +} + +static void virtrng_remove(struct virtio_device *vdev) +{ + vdev->config->reset(vdev); + hwrng_unregister(&virtio_hwrng); + vdev->config->del_vq(vq); +} + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_rng = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = id_table, + .probe = virtrng_probe, + .remove = __devexit_p(virtrng_remove), +}; + +static int __init init(void) +{ + int err; + + random_data = kmalloc(RANDOM_DATA_SIZE, GFP_KERNEL); + if (!random_data) + return -ENOMEM; + + err = register_virtio_driver(&virtio_rng); + if (err) + kfree(random_data); + return err; +} + +static void __exit fini(void) +{ + kfree(random_data); + unregister_virtio_driver(&virtio_rng); +} +module_init(init); +module_exit(fini); + +MODULE_DEVICE_TABLE(virtio, id_table); +MODULE_DESCRIPTION("Virtio random number driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From c97aee9ba43d60ff20d955065d29b6d3d8c950d5 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 12 Jun 2008 15:21:45 -0700 Subject: intel_rng: make device not found a warning Since many distros load this driver by default (throw it against the wall and see what sticks method). Change the error message severity level to avoid alarming users. Isn't it annoying when users actually read the error logs... Signed-off-by: Stephen Hemminger Cc: Michael Buesch Acked-by: Jan Beulich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/hw_random/intel-rng.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/char/hw_random') diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c index 5cc651ef75e..27fdc086649 100644 --- a/drivers/char/hw_random/intel-rng.c +++ b/drivers/char/hw_random/intel-rng.c @@ -273,7 +273,7 @@ static int __init intel_rng_hw_init(void *_intel_rng_hw) if (mfc != INTEL_FWH_MANUFACTURER_CODE || (dvc != INTEL_FWH_DEVICE_CODE_8M && dvc != INTEL_FWH_DEVICE_CODE_4M)) { - printk(KERN_ERR PFX "FWH not detected\n"); + printk(KERN_NOTICE PFX "FWH not detected\n"); return -ENODEV; } -- cgit v1.2.3