virtio-rng: Remove blocking /dev/urandom

It's a bad idea to claim to support /dev/urandom but rely on HW RNG
because starting up Cassandra, for example, takes ages.

Drop it until we have a cryptographically secure PRNG in OSv that can be
used to implement /dev/urandom properly.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

drivers/virtio-rng.cc

@@ -65,10 +65,6 @@ virtio_rng::virtio_rng(pci::device& pci_dev)
 
     struct virtio_rng_priv *prv;
 
-    _urandom_dev = device_create(&virtio_rng_driver, "urandom", D_CHR);
-    prv = to_priv(_urandom_dev);
-    prv->drv = this;
-
     _random_dev = device_create(&virtio_rng_driver, "random", D_CHR);
     prv = to_priv(_random_dev);
     prv->drv = this;
@@ -80,7 +76,6 @@ virtio_rng::virtio_rng(pci::device& pci_dev)
 
 virtio_rng::~virtio_rng()
 {
-    device_destroy(_urandom_dev);
     device_destroy(_random_dev);
 }
 

drivers/virtio-rng.hh

@@ -44,7 +44,6 @@ private:
     std::valarray<char> _entropy;
     gsi_level_interrupt _gsi;
     sched::thread _thread;
-    device* _urandom_dev;
     device* _random_dev;
     u32 _entropy_count;
     condvar _producer;