[Qemu-devel] [QEMU] crypto/random: Fall back to /dev/random when getrandom returns EAGAIN

[Suraj Jitindar Singh]

Hi,

I'm trying to use qemu inside a a guest, however since there isn't
enough entropy for the rng getrandom() blocks. This means I am unable
to even get output from 'qemu --help' for example. This is annoying at
best.

Thinking about ways to work around this obviously the major one is to
have an entropy source for the guest.

In cases where this isn't possible I think it would make sense to fall
back to the old /dev/random source when the getrandom() syscall returns
EAGAIN indicating that it would block.

Alternatively it would be nice to have a config option to disable the
new getrandom interface, along the lines of --disable-getrandom.

If you feel that either of the approaches would be statisfactory I'd be
happy to send a patch. Otherwise if we can have a discussion here with
regards to how to progress.

Kind Regards,
Suraj