Hypervisor exposes mitigation technique for Speculative
Store Bypass(SSB) to guests and allows a guest to determine
whether to enable SSBD mitigation by providing direct guest
access to IA32_SPEC_CTRL.
Before that, hypervisor should check the SSB mitigation support
on underlying processor, this patch is to add this capability check.
Tracked-On: #3385
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
1ea3052f80