From 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce Mon Sep 17 00:00:00 2001 From: Amos Kong Date: Wed, 14 May 2014 10:33:46 +0930 Subject: [PATCH] virtio-rng: support multiple virtio-rng devices Current hwrng core supports to register multiple hwrng devices, and there is only one device really works in the same time. QEMU alsu supports to have multiple virtio-rng backends. This patch changes virtio-rng driver to support multiple virtio-rng devices. ]# cat /sys/class/misc/hw_random/rng_available virtio_rng.0 virtio_rng.1 ]# cat /sys/class/misc/hw_random/rng_current virtio_rng.0 ]# echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current ]# dd if=/dev/hwrng of=/dev/null Signed-off-by: Amos Kong Signed-off-by: Rusty Russell --- drivers/char/hw_random/virtio-rng.c | 102 +++++++++++++++++----------- include/linux/hw_random.h | 2 +- 2 files changed, 64 insertions(+), 40 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 2ce0e225e58c..12e242bbb0f5 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -25,88 +25,108 @@ #include #include -static struct virtqueue *vq; -static unsigned int data_avail; -static DECLARE_COMPLETION(have_data); -static bool busy; + +struct virtrng_info { + struct virtio_device *vdev; + struct hwrng hwrng; + struct virtqueue *vq; + unsigned int data_avail; + struct completion have_data; + bool busy; +}; static void random_recv_done(struct virtqueue *vq) { + struct virtrng_info *vi = vq->vdev->priv; + /* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */ - if (!virtqueue_get_buf(vq, &data_avail)) + if (!virtqueue_get_buf(vi->vq, &vi->data_avail)) return; - complete(&have_data); + complete(&vi->have_data); } /* The host will fill any buffer we give it with sweet, sweet randomness. */ -static void register_buffer(u8 *buf, size_t size) +static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size) { struct scatterlist sg; sg_init_one(&sg, buf, size); /* There should always be room for one buffer. */ - virtqueue_add_inbuf(vq, &sg, 1, buf, GFP_KERNEL); + virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL); - virtqueue_kick(vq); + virtqueue_kick(vi->vq); } static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) { int ret; + struct virtrng_info *vi = (struct virtrng_info *)rng->priv; - if (!busy) { - busy = true; - init_completion(&have_data); - register_buffer(buf, size); + if (!vi->busy) { + vi->busy = true; + init_completion(&vi->have_data); + register_buffer(vi, buf, size); } if (!wait) return 0; - ret = wait_for_completion_killable(&have_data); + ret = wait_for_completion_killable(&vi->have_data); if (ret < 0) return ret; - busy = false; + vi->busy = false; - return data_avail; + return vi->data_avail; } static void virtio_cleanup(struct hwrng *rng) { - if (busy) - wait_for_completion(&have_data); + struct virtrng_info *vi = (struct virtrng_info *)rng->priv; + + if (vi->busy) + wait_for_completion(&vi->have_data); } - -static struct hwrng virtio_hwrng = { - .name = "virtio", - .cleanup = virtio_cleanup, - .read = virtio_read, -}; - static int probe_common(struct virtio_device *vdev) { - int err; + int err, i; + struct virtrng_info *vi = NULL; + + vi = kmalloc(sizeof(struct virtrng_info), GFP_KERNEL); + vi->hwrng.name = kmalloc(40, GFP_KERNEL); + init_completion(&vi->have_data); + + vi->hwrng.read = virtio_read; + vi->hwrng.cleanup = virtio_cleanup; + vi->hwrng.priv = (unsigned long)vi; + vdev->priv = vi; - if (vq) { - /* We only support one device for now */ - return -EBUSY; - } /* We expect a single virtqueue. */ - vq = virtio_find_single_vq(vdev, random_recv_done, "input"); - if (IS_ERR(vq)) { - err = PTR_ERR(vq); - vq = NULL; + vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input"); + if (IS_ERR(vi->vq)) { + err = PTR_ERR(vi->vq); + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; return err; } - err = hwrng_register(&virtio_hwrng); + i = 0; + do { + sprintf(vi->hwrng.name, "virtio_rng.%d", i++); + err = hwrng_register(&vi->hwrng); + } while (err == -EEXIST); + if (err) { vdev->config->del_vqs(vdev); - vq = NULL; + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; return err; } @@ -115,11 +135,15 @@ static int probe_common(struct virtio_device *vdev) static void remove_common(struct virtio_device *vdev) { + struct virtrng_info *vi = vdev->priv; vdev->config->reset(vdev); - busy = false; - hwrng_unregister(&virtio_hwrng); + vi->busy = false; + hwrng_unregister(&vi->hwrng); vdev->config->del_vqs(vdev); - vq = NULL; + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; } static int virtrng_probe(struct virtio_device *vdev) diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index b4b0eef5fddf..02d9c87be54c 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -31,7 +31,7 @@ * @priv: Private data, for use by the RNG driver. */ struct hwrng { - const char *name; + char *name; int (*init)(struct hwrng *rng); void (*cleanup)(struct hwrng *rng); int (*data_present)(struct hwrng *rng, int wait);