OK, lets check.
1) "Microsoft’s latest Windows 10 patch will address Spectre Variant 2 CPU flaw
Microsoft now provides a new manual update for Windows 10 devices based on sixth-generation Intel processors. It addresses the Spectre Variant 2 flaw in these CPUs, which could give hackers access to sensitive information if they have direct contact with the device."
Go through the link
2) "KB4090007: Intel microcode updates
Applies to: Windows 10 version 1709Windows Server, version 1709 (Datacenter, Standard)
Summary
Intel recently announced that they have completed their validations and started to release microcode for newer CPU platforms around Spectre Variant 2 (CVE 2017-5715 (“Branch Target Injection”))."
Also in the end:
"Consult with your device manufacturer’s and Intel’s websites regarding their microcode recommendation for your device before applying this update to your device."
Clicking on "recently announced"
3)"Latest Intel Security News: Updated Firmware Available for 6th, 7th and 8th Generation Intel Core Pr...
The new microcode will be made available in most cases through OEM firmware updates."

>through OEM firmware updates

BIOS update needed so. If you check Windows Client Guidance for IT Pros to protect against speculative execution side-channel vulnerabil..., you will see:
BTIHardwarePresent : True (Hardware support for branch target injection mitigation is present)
BTIWindowsSupportPresent : True (Windows OS support for branch target injection mitigation is present)
BTIWindowsSupportEnabled : False (Windows OS support for branch target injection mitigation is not enabled)
BTIDisabledBySystemPolicy : False
BTIDisabledByNoHardwareSupport : True (branch target injection mitigation has no hardware support - no microcide update from vendor)
KVAShadowRequired : True
KVAShadowWindowsSupportPresent : True
KVAShadowWindowsSupportEnabled : True
KVAShadowPcidEnabled : True