On 02/19/13 14:21, John Ferlan wrote:
On 02/13/2013 11:28 AM, Peter Krempa wrote:
Qemu's implementation of virtio RNG supports rate limiting of the entropy used. This patch exposes the option to tune this fucntionality.
s/fucntionality/functionality
This patch is based on qemu commit 904d6f588063fb5ad2b61998acdf1e73fb4
The rate limiting is exported in the XML as: <devices> ... <rng model='virtio'> <rate period='1234'>4321</rate> <backend model='random'/> </rng> ... --- docs/formatdomain.html.in | 9 +++++++++ docs/schemas/domaincommon.rng | 18 +++++++++++++++++- src/conf/domain_conf.c | 17 +++++++++++++++++ src/conf/domain_conf.h | 2 ++ src/qemu/qemu_command.c | 8 ++++++++ .../qemuxml2argv-virtio-rng-random.args | 2 +- .../qemuxml2argv-virtio-rng-random.xml | 1 + 7 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index e8cd086..b264460 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -4293,6 +4293,7 @@ qemu-kvm -net nic,model=? /dev/null ... <devices> <rng model='virtio'> + <rate period="2000">1234</rate> <backend model='random'>/dev/random</backend> <!-- OR --> <backend model='egd' type='udp'> @@ -4315,6 +4316,14 @@ qemu-kvm -net nic,model=? /dev/null <li>'virtio' — supported by qemu and virtio-rng kernel module</li> </ul> </dd> + <dt><code>rate</code></dt> + <dd> + <p> + The rate parameter allows to limit the rate that the entropy can be + read from the source. The value is in bits that the device is allowed + to read in the selected period. The default period is 1000ms or 1 second. + </p> + </dd>
bits or bytes?
qemu uses bits for it's configuration value. As the expected data rades are pretty low, I think bits can be used and potentially divided to larger values if needed. Peter