IBM already released patches for this, at least for POWER7+. Interestingly the Meltdown issue seems "only" to affect the L1 cache, so L2 does not need to be evicted. Raptor says all Talos systems will be patched prior to shipping.
Patching POWER for Spectre/Meltdown was a pain but we are done with it.
You have to apply patches to the LPAR/OS, VIOS and firmware. IBM has acknowledged that there will be a performance hit but have not provided any quantified numbers that I have seen so far.
"All POWER8 and POWER9 results in this table reflect performance with firmware and Operating System updates to
mitigate Common Vulnerabilities and Exposures issue numbers ... known as Spectre and Meltdown"
How did you verify if the patched system is not affected anymore? I'm really curious what means the users have to verify the effectiveness of such patches.
https://wiki.raptorcs.com/wiki/Speculative_Execution_Vulnera...