On Fri, 2018-10-26 at 09:59 -0400, Hongxu Jia wrote: > Just adding `-device virtio-rng-pci' to the QEMU invocation will > add the device with a default host backend. As of QEMU 1.3+, > the default backend is to use the host's /dev/random as a > source of entropy. [1] > > When the entropy pool is empty, reads from /dev/random will > block until additional environmental noise is gathered. [2] > > For Yocto, if call runqemu frequently, it will consume lots > of host's /dev/random, and kernel finish crng init in guest get > more and more slowly. > > Here are 4 times runqemu boot test: > > [ 3.464432] random: crng init done > [ 20.874030] random: crng init done > [ 23.583589] random: crng init done > [ 23.858945] random: crng init done > > Modify entropy source to /dev/urandom device on the host which > returns random bytes using a pseudorandom number generator seeded > from the entropy pool. Reads from this device do not block and > kernel finish crng init in guest will not delay. > > Of course, the side effect is obviously, we lost the quality of > randomness, but the modification is only on runqemu script > rather than real embedded device, and it benefits oeqa efficiency > in which many cases call runqemu especially multiple oeqa builds > on one host. > > After apply the fix: > > [ 3.364670] random: crng init done > [ 4.619061] random: crng init done > [ 3.403897] random: crng init done > [ 3.450717] random: crng init done > > [1] https://wiki.qemu.org/Features/VirtIORNG > [2] http://man7.org/linux/man-pages/man4/random.4.html > > Signed-off-by: Hongxu Jia <hongxu....@windriver.com> > --- > meta/conf/machine/include/qemuboot-mips.inc | 3 ++- > meta/conf/machine/include/qemuboot-x86.inc | 3 ++- > meta/conf/machine/qemuarm.conf | 3 ++- > meta/conf/machine/qemuarm64.conf | 4 +++- > meta/conf/machine/qemuppc.conf | 3 ++- > 5 files changed, 11 insertions(+), 5 deletions(-)
Doesn't work unfortunately, e.g.: https://autobuilder.yoctoproject.org/typhoon/#/builders/21/builds/155/steps/7/logs/step1c Cheers, Richard -- _______________________________________________ Openembedded-core mailing list Openembedded-core@lists.openembedded.org http://lists.openembedded.org/mailman/listinfo/openembedded-core