AMD does not provide microcode updates directly. The two avenues available for microcode patches are through the system BIOS or through the host operating system. I don't know if Microsoft supplies this microcode patch, but you should check to see if there are any relevant Windows updates available. I would assume that Hyper-V is impacted by this erratum as well.
The only workaround is to disable hardware-assisted virtualization. Binary translation should work fine. However, you will not be able to run nested VMs with binary translation.
If Microsoft doesn't supply the patch, it is possible that a Linux distribution may supply the patch. One potential solution is to install a recent Linux distribution on your host, along with the latest AMD microcode package available.