Linux PM emulator boot process

I see the nvdimm can be emulated through the kernel, so I'm wondering about the boots process.

Comunicating with Jiachen, The operating system has no knowledge of a PCIe system

CXL possible boot up process

Reference

1. https://nvdimm.wiki.kernel.org/how_to_choose_the_correct_memmap_kernel_parameter_for_pmem_on_your_system
2. https://elixir.bootlin.com/linux/v6.0-rc7/source