HyperCalc

An Intel HAXM powered, protected mode, 32 bit, hypervisor addition calculator, written in Rust.

Purpose

None 😏. Mostly just to learn Rust better. Especially looking at the winapi crate.

Requirements

• HAXM for Windows

Notes

Lots of unsafe Rust used. Some things I found interesting related to working with HAXM:

• ~~Real mode is expected to be handled by the user mode component which is usually listed as QEMU. Make sure CR0.PE is set!~~ HAXM does actually allow for real mode if the processor allows/exposes the unrestricted guest VM-execution control.
• It is not required to register a vCPU tunnel to actually run a VM. However if you do you can get extra information such as the VM-exit code.
• Some registers have default values set by HAXM for a newly created vCPU. These include the DR6, and DR7 registers. This happens if after creating a new vCPU you first call HAX_VCPU_GET_REGS.
• The vcpu_state_t is essentially just a limited version of a VMCS.
• Remember that VMCS fields may not be sized accurately to what they reflect in an actual OS. I'm looking at you segment descriptors limits!🧐
• The Descriptor Cache (https://wiki.osdev.org/Descriptor_Cache)

Useful resources:

• HAXM Device API
• Semi-Working Example