Comment 4 for bug 1703506

I can confirm the same behavior with a Ryzen 7 1700.
Host Arch Linux x64 Kernel 4.11.9, Guest Windows 10 Pro.
Running with -cpu host and -smp 8,sockets=1,cores=4,threads=2.
Attached the logs of the host and results of the output of msinfo32 and "WMIC CPU Get NumberOfCores,NumberOfLogicalProcessors /Format:List" in the guest.
Same results as scix, in my case 8 Core(s), 8 Logical Processors(s).

This seems relevant: https://bugzilla.redhat.com/show_bug.cgi?id=1135772
And a few extra reports on reddit:
https://www.reddit.com/r/VFIO/comments/6nuhb5/big_problem_with_my_ryzen_1700x/
https://www.reddit.com/r/VFIO/comments/6m6kry/smthyperthreading_support_with_ryzen_cpu_and/

I'll test with a Linux guest later.