Hello, is anyone here wanting to develop hypervisors for AMD or Intel?
I do not know in which subsection of the forum start this thread. I found the most suitable subsection in OS development. If administrators decide to move it to better subforum please do it.
The development is closest to OS development. If you are able to write you own tiny x64 OS (look for Tomasz example 'Entering long mode' from FASM examples) you are very likely able to do hypervisor development as well.
Hypervisor or your skills could be used for these purposes: secretly watch OS, run few virtual machines on one CPU (only as a part of a team and using C programming language), research vulnerabilities of already used hypervisors.
I was doing hypervisors development for the past 15 years since AMD FX and Intel Core 2 Duo launched (core 2 duo was limited to start hypervisor only from ms win driver due to lack of real mode virtualization, core i had already features for real mode virtualization to launch hypervisor easily from BIOS and UEFI).
Hypervisor could be started from UEFI (UEFI runtime driver / UEFI boot executable / UEFI application from UEFI shell), BIOS (similarly as bootkit) or from running OS (e.g. ms win x64 driver) - I implemented all of these 3 ways.
If anyone interested, I will post at first some easy to understand examples for paging, how to write system structures (VMCB for AMD, VMCS for Intel), how a VM exit handler could look like, some examples to debug/trace in emulators (SimNow 4.6.2, BOCHS). You will need to study CPU manuals, expect something like 1000 pages for Intel and 500 pages for AMD, AMD manuals are more compact than Intel, but the amount of information is comparable).
Before even starting I would like to warn you that debugging could be a nightmare especially on hardware and best if you have a machines with serial ports connected with null modem serial cable. But the development and tests are usually done in emulators and only then you finally retest on real hardware (baremetal). If you are not very very very patient or you are unable to withstand weeks of debugging without seeing progress (trying to find a bug in your work) you should rather do something else to prevent your hair get gray or even losing your hair from head entirely.
There are some published C source code for hypervisors but most of them just copy/paste someone else' work without deep understanding. We will of course write hypervisors in FASM. To have some idea and estimation about its size, the simplest hypervisor written in FASM could be around 8 kB binary, maybe it could be pushed into 5 KB, but rather expect 8 kB.
If you would like to secretly watch/monitor ms windows OS, they added detections for hypervisors (KiErrata704Present, KiErrataSkx55Present, KiErrata671Present, KiErrata361Present) but the detections are harmless for properly written hypervisor. Also today ms windows OS enables hyper-v by default, then your hypervisor may pretend virtualization not present or disabled so hyper-v does not start or it is possible to add nesting (here you can expect your hypervisor size to grow to around 32 kB binary).
To start a hypervisor at all CPUs/cores/threads, I can explain APIC INIT-SIPI interprocessor interrupts (when started from BIOS) or multiprocessor UEFI calls (when started from UEFI), or ms win x64 interprocessor kernel calls (when started from ms win driver).
Suspend and resume from S3 also disables virtualization, but it can be hooked so hypervisor survives.
Simple hypervisor with static paging tables covering terra/petabytes of RAM running on 64 CPUs/cores/threads can consume upto 16 MB of RAM even its binary only 8 kB, every CPU core may consume upto 16-32 kB of RAM (stack + system structures), paging tables may consume slightly more than 4 MB for physical memory virtualization and slightly more than 4 MB for hypervisor virtual memory with identity map of the whole physical memory.
I won't help any newly registered member unless proven not to be malware creator.
I will help and cooperate with active forum members with long enough history of posts where it is clear that they are peaceful, helpful to other FASM forum members.

Unfortunately I don't have time for that. But I appreciate that you are willing to share your knowledge on this advanced topic.

Hello,Feryno
I appreciate your ideal. but is this possible? This should be an act of the state, not the act of certain individuals.

1, You should maintain a development team of at least 5000 people per year, including an office and salary. this will run for 20 years.
2, M$ is there, preemptively occupied this track. Many CPU manufacturers have always supported him. could you done better than him?