Have you ever thought how transitions between different rings performed? Well, SYSENTER & SYSCALL used in modern OSs for transitioning between ring 3 to ring 0 but if there are other rings, then what’s Intel solution for entering them? The answer is call gates. The rest of this topic described how to use call gates in modern processors. 80386 and its successors have 4 levels protections which isolate and protect user programs from each other and the operating system. It…
Posts published by “Sinaei”
Sven, are you still so blue under that armor?
Introduction Hello and welcome back to the fifth part of the “Hypervisor From Scratch” tutorial series. Today we will be configuring our previously allocated Virtual Machine Control Structure (VMCS) and in the last, we execute VMLAUNCH and enter to our hardware-virtualized world! Before reading the rest of this part, you have to read the previous parts as they are really dependent. The full source code of this tutorial is available on GitHub : [https://github.com/SinaKarvandi/Hypervisor-From-Scratch] Most of this topic derived from…
Introduction If you’ve ever had experience with developing your own hypervisor from scratch then you definitely faced with the problems of layout checking. What makes it hard to develop a hypervisor is the fact that Intel has a small number of errors for a huge checklist described in [CHAPTER 26] VM ENTRIES from Intel’s 64 and IA-32 Architectures Software Developer’s Manual including: 26.2 CHECKS ON VMX CONTROLS AND HOST-STATE AREA 26.3 CHECKING AND LOADING GUEST STATE 26.4 LOADING MSRS 26.5 EVENT…
Hello guys! Welcome to the fourth part of the “Hypervisor From Scratch”. This part is primarily about translating guest address through Extended Page Table (EPT) and its implementation. We also see how shadow tables work and other cool stuff. First of all, make sure to read the earlier parts before reading this topic as these parts are really dependent on each other also you should have a basic understanding of paging mechanism and how page tables work. A good article is…
Introduction This is the third part of the tutorial “Hypervisor From Scratch“. You may have noticed that the previous parts have steadily been getting more complicated. This part should teach you how to get started with creating your own VMM, we go to demonstrate how to interact with the VMM from Windows User-mode (IOCTL Dispatcher), then we solve the problems with the affinity and running code in a special core. Finally, we get familiar with initializing VMXON Regions and VMCS…