Switch to using qcrypto_random_bytes() rather than rand() as
our source of randomness for the BCM2835 RNG.
If qcrypto_random_bytes() fails, we don't want to return the guest a
non-random value in case they're really using it for cryptographic
purposes, so the best we can do is a fatal error. This shouldn't
happen unless something's broken, though.
In theory we could implement this device's full FIFO and interrupt
semantics and then just stop filling the FIFO. That's a lot of work,
though, and doesn't really give a very nice diagnostic to the user
since the guest will just seem to hang.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Recent vanilla Raspberry Pi kernels started to make use of
the hardware random number generator in BCM2835 SoC. As a
result, those kernels wouldn't work anymore under QEMU
but rather just freeze during the boot process.
This patch implements a trivial BCM2835 compatible RNG,
and adds it as a peripheral to BCM2835 platform, which
allows to boot a vanilla Raspberry Pi kernel under Qemu.
Changes since v1:
* Prevented guest from writing [31..20] bits in rng_status
* Removed redundant minimum_version_id_old
* Added field entries for the state
* Changed realize function to reset
Signed-off-by: Marcin Chojnacki <marcinch7@gmail.com>
Message-id: 20170210210857.47893-1-marcinch7@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
