I've tested the changes (all four patches) on a Ryzen 5 5600X processor running -CURRENT.
The kernel and the vmm module were compiled with assertions enabled.
Setting breakpoints and single-stepping works, and stepping over POPF/PUSHF correctly preserves the TF bit.
There is, however, a chance that single-stepping will get randomly interrupted by `cpu_idle_acpi`.
That issue is also present on Intel CPUs and I'll look into it separately.
The virtual machine ran fine after detaching the debugger and running `buildkernel`.