Re: Bull Mountain (IvyBridge +) random number generator

 schrieb Konstantin Belousov am 02.09.2012 12:34 (localtime):
> It is relatively well known that Ivy Bridge CPUs (Core iX 3XXX) have
> built-in hardware random number generator, which is claimed to be both
> very fast and high quality. Generator is accessible using non-privileged
> RDRAND instruction. It is claimed that CPU performs sanitization of the
> random sequence. In particular, it seems that paranoid AES encryption of
> the raw random stream, performed by our padlock driver, is not needed
> for Bull Mountain (there are hints that hardware performs it already).
>
> See
> http://spectrum.ieee.org/computing/hardware/behind-intels-new-randomnumber-generator/0
> http://software.intel.com/en-us/articles/intel-digital-random-number-generator-drng-software-implementation-guide/
> and IA32 ADM.
>
> Patch at
> http://people.freebsd.org/~kib/misc/bull_mountain.2.patch
> implements support for the generator. I do not own any IvyBridge machines,
> so I cannot test. Patch makes both padlock and bull generators the options,
> you need to enable IVY_RNG to get support for the generator.
>
> I would be interested in seeing reports including verbose boot dmesg,
> and some tests of /dev/random quality on the IvyBridge machines, you can
> start with http://lists.gnupg.org/pipermail/gnupg-devel/2000-March/016328.html.

Thanks a lot for implementing this!
I have an ESXi host with Ivy Brindge CPU.
FreeBSD guest reports the following:
CPU: Intel(R) Xeon(R) CPU E3-1270 V2 _at_ 3.50GHz (3492.07-MHz K8-class CPU)
  Origin = "GenuineIntel"  Id = 0x306a9  Family = 6  Model = 3a 
Stepping = 9
 
Features=0x1fa3fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,DTS,MMX,FXSR,SSE,SSE2,SS,HTT>
 
Features2=0xfeba2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND,HV>
  AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant
real memory  = 8589934592 (8192 MB)
avail memory = 8235110400 (7853 MB)
Event timer "LAPIC" quality 600
ACPI APIC Table: <PTLTD       APIC  >
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
FreeBSD/SMP: 1 package(s) x 4 core(s)
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
 cpu2 (AP): APIC ID:  2
 cpu3 (AP): APIC ID:  3
MADT: Forcing active-low polarity and level trigger for SCI

But unfortunately accessing /dev/random doesn't work with IVY_RNG enabled.
'dd' consumes 100% wcpu bound to one core but never finishes (dd
if=/dev/random bs=1k count=100|./ent)
Also some other functions are blocked, logging in for example (doesn't
matter if it's console or ssh). But I can walk arround in already
established sessions.

I made a 9.1-RC-2 debug kernel but no info appears. Also IVY_RNG isn't
reported after kldloading, nor during boot, but this is the expected
behaviour if I unterstand your patch correctly.

I guess using RDRAND in an hypervisor environment should make no
difference but please correct me if I'm wrong.

Thanks,

-Harry