Query about "Speculative Execution" Bug and RHEL Hosted In Virtualized Environments

If the virtualization layer (say, AWS, Azure, etc.) has been remediated and the CSP is eating the 30% hit at the hardware level, are guests riding that CSP hardware going to take a further 30% hit against their CPU allocation? Or, does the remediation set some kind of flag that gets passed up from the virtualization layer so that the fix-code sees "already safe - nothing for me to do at this layer"?