Deeper look into guest-mode transition

• Switching to the guest-mode

  • Intel
    • VMLAUNCH - used for first transition with the VMCS
    • VMRESUME - used for subsequent transitions
  • AMD: VMRUN

• Our implementation:

  	AMD: run_vm_svm()	Intel: run_vm_vmx()
  1	Save host GPRs into stack	Save host GPRs into stack
  2	Load guest GPRs from memory	Load guest GPRs from memory
  3	VMRUN	if launched { VMRESUME } else { set up host RIP and RSP, then VMLAUNCH }
  4	Save guest GPRs into memory	Save guest GPRs into memory
  5	Load host GPRs from stack	Load host GPRs from stack

• Contents of the GPRs are manually switched, because the VMRUN, VMLAUNCH, VMRESUME instructions do not do it