Looks like it is still working in a guix VM running on AMD ryzen 3700X host.

But there is some output differences between previous version and this one.

in raw mode (cpuid -r), it outputs one more line per core:

0x20000000 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000

which is probably OK, looks like the change:
Sun Feb  2 2020 Todd Allen <todd.allen@etallen.com>
        * cpuid.c: Added leaf walking of the 0x20000000 (Intel Phi) range
        [...]

But in normal mode, output changed a lot, some separators changed from ":"
to "=", a lot of reported values, new things... This will probably break
any simplistic parsing of that output, if there is anything doing that in
guix...

Having a cursory look at the changelog, it looks like this is getting a lot
more change since the beginning of this year, or something else.

Maybe Tood Allen can give us a hint...

Guixers, please advise how to proceed further.

Thanks--
Vincent Legoll