Disclosure: I used to work on GCE.

Nice write up and very clever work. I'm surprised by the AWS response that you linked to though (https://aws.amazon.com/blogs/security/ec2-defenses-against-l...).

While I was sure they'd note that Nitro doesn't have this vulnerability due to its design, it seems weird not to talk about Firecracker and Lambda and so on. Maybe those are always on Cascadelake+ hardware? (I also haven't followed this space for 5 years, so maybe I'm asking the wrong question)