Does Windows 7 have PCID optimization?
Is PCID supported for Windows 7? I've updated two Windows 7 systems on CPUs that claim to have both PCID and INVPCID support, but that support doesn't show as enabled.
I used the Powershell 5.1 Get-SpeculationControlSettings function to check. (See https://support.microsoft.com/en-hk/help/4073119/guide-to-protect-against-speculative-execution-side-channel-vulnerabil ).
"Speculation control settings for CVE-2017-5754 [rogue data cache load]
Hardware requires kernel VA shadowing: True
Windows OS support for kernel VA shadow is present: True
Windows OS support for kernel VA shadow is enabled: True
Windows OS support for PCID optimization is enabled: False
BTIHardwarePresent : False
BTIWindowsSupportPresent : True
BTIWindowsSupportEnabled : False
BTIDisabledBySystemPolicy : False
BTIDisabledByNoHardwareSupport : True
KVAShadowRequired : True
KVAShadowWindowsSupportPresent : True
KVAShadowWindowsSupportEnabled : True
KVAShadowPcidEnabled : False"
I booted Mobile Windows 10 on one of these systems, and under Windows 10 it does show
"Windows OS support for PCID optimization is enabled: True".
So, I was wondering if they've omitted PCID optimization under Windows 7.