Nitro support for Legacy EC2 instances

As the article states, the hardware and hypervisor backend is transparent -- this is not something exposed as it is not pertinent to the use/operation of the instances. The best information as to where a particular instance runs is based off the bolded statement (from the article) below regarding when the instance was launched and that running instances will be migrated.

All of these innovations enable us to continue to offer many of our older instance types well past the lifetime of the original hardware. Starting in 2022, customers launching M1, M2, M3, C1, C3, R3, I2 and T1 instances will land on Nitro supported instances hardware and existing running instances will also be migrated. Whether the instance runs on the original hardware or newer Nitro hardware will be fully transparent to customers. Workloads will continue to run just like they have run before. Later we will also support C4, M4, R4 and T2 instance types.