Re: regarding the changes to kernel entropy gathering

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sun, Apr 04, 2021 at 06:47:23PM -0700, Brian Buhrow wrote:
> Hello.  As I understand it, Greg ran into this problem on a xen domu.  In checking my NetBSD-9
> system running as a domu under xen-4.14.1, there is no rdrand or rdseed feature exposed to
> domu's by xen.  This observation is confirmed by looking at the xen command line reference
> page: https://xenbits.xen.org/docs/unstable/misc/xen-command-line.html

Actually, if the CPU supports rdrand or rdseed, they are available
to domUs:
cpu0: Running on hypervisor: Xen
cpu0: "Intel(R) Xeon(R) Silver 4208 CPU @ 2.10GHz"
cpu0: Intel Xeon Scalable (Skylake, Cascade Lake, Copper Lake) (686-class)
cpu0: family 0x6 model 0x55 stepping 0x7 (id 0x50657)
[...]
cpu0: features1 0xf6f81203<POPCNT,AES,XSAVE,AVX,F16C,RDRAND,RAZ>
cpu0: features2 0x8100000<XD,RDTSCP>
cpu0: features5 0xd18f2369<AVX512F,AVX512DQ,RDSEED,ADX,CLFLUSHOPT,CLWB>

Source                 Bits Type      Flags
xbd0                4010273 disk estimate, collect, v, t, dt
xennet0                   0 net  v, t, dt
cpu0                  88774 vm   estimate, collect, v, t, dv
system-power              0 power estimate, collect, v, t, dt
autoconf                  1 ???  estimate, collect, t, dt
printf                    0 ???  collect
callout                 108 skew estimate, collect, v, dv
cpurng                 4096 rng  estimate, collect, v


-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--