2018-10-05 07:39:40 +08:00
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.. _virtio-rnd:
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Virtio-rnd
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##########
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2018-11-07 03:33:24 +08:00
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virtio-rnd provides a hardware random source for UOS. The
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virtual random device is based on virtio user mode framework and
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simulates a PCI device based on virtio specification.
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:numref:`virtio-rnd-arch` shows the Random Device Virtualization
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Architecture in ACRN. virtio-rnd is implemented as a virtio legacy
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device in the ACRN device model (DM), and is registered as a PCI virtio
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device to the guest OS (UOS).
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2018-10-05 07:39:40 +08:00
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When the FE driver requires some random bytes, the BE device will place
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bytes of random data onto the virtqueue.
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2018-11-07 03:33:24 +08:00
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Tools such as ``od`` can be used to read randomness from
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``/dev/random``. This device file in UOS is bound with frontend
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virtio-rng driver (The guest kernel must be built with
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``CONFIG_HW_RANDOM_VIRTIO=y``). The backend virtio-rnd reads the HW
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randomness from ``/dev/random`` in SOS and sends them to frontend.
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.. figure:: images/virtio-hld-image61.png
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:align: center
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:name: virtio-rnd-arch
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Virtio-rnd Architecture on ACRN
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2018-10-05 07:39:40 +08:00
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To launch the virtio-rnd device, use the following virtio command::
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-s <slot>,virtio-rnd
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To verify the correctness in user OS, use the following
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command::
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od /dev/random
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