random: Providing a seed value to VM guests

[H. Peter Anvin]

On 05/01/2014 11:53 AM, Andy Lutomirski wrote:
> 
> A CPUID leaf or an MSR advertised by a CPUID leaf has another
> advantage: it's easy to use in the ASLR code -- I don't think there's
> a real IDT, so there's nothing like rdmsr_safe available.  It also
> avoids doing anything complicated with the boot process to allow the
> same seed to be used for ASLR and random.c; it can just be invoked
> twice on boot.
> 

At that point we are talking an x86-specific interface, and so we might
as well simply emulate RDRAND (urandom) and RDSEED (random) if the CPU
doesn't support them.  I believe KVM already has a way to report CPUID
features that are "emulated but supported anyway", i.e. they work but
are slow.

> What's the right forum for this?  This thread is probably not it.

Change the subject line?

	-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/