The Linux patch appears to reload the Ring 0 TLBs and then flush them at every system call, which is a huge performance hit.
As far as I know that's the fix Intel has provided to Microsoft to be used in their update rolling out today. There is no true fix besides replacing the CPU. The "fix"es are just workarounds that come at a big price.
Some theoretical benchmarks are showing 15-30% performance decrease. Imagine waking up tomorrow and your data center is now 30% less powerful as it was yesterday. The lawsuits against Intel are probably already being filed. Any other industry would have forced a recall over this but that would bankrupt Intel.