.\" $NetBSD: viornd.4,v 1.2 2014/10/26 22:07:47 wiz Exp $
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.\" Copyright (c) 2014 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Thor Lancelot Simon.
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.Dd October 26, 2014
.Dt VIORND 4
.Os
.Sh NAME
.Nm viornd
.Nd VirtIO entropy source
.Sh SYNOPSIS
.Cd "viornd* at virtio?"
.Sh DESCRIPTION
When the system has entropy demand,
the
.Nm
driver, used with a compatible hypervisor such as QEMU, KVM, or Google
Compute Engine, requests entropy using the VirtIO random number interface
and feeds it into the system entropy pool.
.Sh SEE ALSO
.Xr rnd 4 ,
.Xr virtio 4
.Sh HISTORY
The
.Nm
driver appeared in
.Ox 5.5 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Stephan Fritsch Aq Mt sf@fritsch.de
and reworked to request entropy upon demand by
.An Thor Lancelot Simon Aq Mt tls@NetBSD.org .
.Sh CAVEATS
VirtIO appears to support at least 8 pending entropy requests, but
.Nm
currently supports only one pending request at a time.