Random Numbers in Virtual Machines

Re:Random Numbers in Virtual Machines by rwmj on Monday March 23, 2015 @03:01PM (#9252728)

Modern Intel processors have an RDRAND instruction which (cue conspiracy theorists) is a hardware RNG. https://en.wikipedia.org/wiki/RdRand

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Re:Random Numbers in Virtual Machines by amitshah on Monday March 23, 2015 @03:06PM (#9252763)

However, it's RDSEED that needs to be used as input if we use the Intel instructions.

https://software.intel.com/en-us/blogs/2012/11/17/the-differ...

Edit to add: we can obviously pass on the RDRAND instruction directly to the VM, but that's less portable, because not all servers in a server farm may have that instruction available, limiting live migration capabilities.

So we can just pass on output from RDSEED into the host's /dev/random, and feed the VM /dev/random by default as described.

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