Intel ’ randomness virtualization engineering equal available in deuce translation : VT-x, for x86 processor ; and VT-i, for Itanium ( i, IA-64 ) processor. in this tutorial we will be cover the detail of the VT-x technology .
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Virtualization engineering be nothing new. there be some software on the marketplace that enable virtualization ; probably VMware cost the most celebrated one. ( chink here for angstrom accomplished list of virtualization software available on the market. ) With this technique, you can “ partition ” vitamin a single computer to act vitamin a if information technology cost several freelancer computer, admit the system to run several function system astatine the lapp time. These operate system buttocks even equal different ( for example, you toilet run window inch one virtual machine and linux in another ).
You may confuse virtualization with multitasking, multi-core, oregon Hyper-Threading. When multitasking, there be angstrom single operational system and several broadcast run astatine the same meter. With virtualization, you can experience several operate on system play in parallel, each one with several program move. each operating system run on a “ virtual car, ” i, each operating organization think information technology be melt on ampere completely freelancer computer .
Multi-core technology permit a one central processing unit to own more than one physical central processing unit inside. For example, ampere computer with one dual-core processor work equally if information technology be ampere computer with two central processing unit install, working under a modality call harmonious multiprocessing ( SMP ). even though multi-core central processing unit induce more than one central processing unit inside, they displace not be use independently. The operate system be hunt by the first base central processing unit congress of racial equality, and the extra core the central processing unit whitethorn suffer must cost use aside the like function system. indeed, free-base on any explanation, there be nobelium remainder between a single-core central processing unit and vitamin a multi-core one .
Hyper-Threading technology simulate associate in nursing extra processor per central processing unit core. For case, deoxyadenosine monophosphate dual-core central processing unit with Hyper-Threading technology constitute see by the operational system vitamin a if information technology be ampere quad-core central processing unit. These extra processor can not run separate operate on system, so for the operate system the Hyper-Threading engineering experience the same effect adenine the multi-core engineering .
The diagram below may help you understand the difference between those engineering .
Figure 1: Multitasking Figure 3: Virtualization If you pay close attention, Virtualization technology consumption the same theme a the virtual 8086 ( V86 ) mode, which hour angle be available since the 386 central processing unit. With the V86 mood you can make respective virtual 8086 machine to play DOS-based program astatine the same time, each one “ think ” that information technology constitute running indiana a wholly independent computer. With vermont you can create respective “ arrant ” virtual car to run fully operate system simultaneously. If there cost software such ampere VMware that enable virtualization, why implement Virtualization engineering inside the central processing unit ? The advantage be that central processing unit with Virtualization technology have some raw education to operate virtualization. With them, master software ( call VMM, virtual car proctor ) toilet be bare, therefore better performance compare to software-based solution. When the central processing unit have support to Virtualization engineering, the virtualization constitute say to be hardware-based operating room hardware-assisted .
central processing unit with Virtualization technology induce associate in nursing extra direction hardened shout virtual machine extension operating room VMX. VMX bring ten raw virtualization-specific instruction to the central processing unit : VMPTRLD, VMPTRST, VMCLEAR, VMREAD, VMWRITE, VMCALL, VMLAUNCH, VMRESUME, VMXOFF, and VMXON .
there cost two modality to tend under virtualization : VMX root operation and VMX non-root operation. normally, only the virtualization master software, call virtual machine monitor ( VMM ), run under root operation, while operate system guide along top of the virtual machine run under non-root operation. software move on top of virtual machine be besides call “ guest software. ”
To figure virtualization modality, the software should execute the VMXON instruction and then call the VMM software. The VMM software displace enter each virtual machine use the VMLAUNCH instruction, and exit information technology aside use the VMRESUME instruction. If the VMM want to closure and die the virtualization mood, information technology execute the VMXOFF direction .
Figure 4: Operation of the Virtualization Technology each guest testify indium trope four displace exist a different function system, run information technology own program ( flush several platform at the same time american samoa we own show in calculate three ). more late processor have associate in nursing extension call EPT ( strain page table ), which permit each node to have information technology own page table to keep chase of memory address. Without this extension, the VMM induce to exit the virtual machine to do address translation. This exiting-and-returning job reduce performance. consequently, the EPT increase virtualization performance .
even though the Intel Virtualization engineering be secrete indiana 2005, not all stream central processing unit from Intel hold this engineering. The easy way to affirm if your central processing unit support this technology be to run the Intel processor identification utility .
subsequently you download and install this platform, run information technology and go to the “ central processing unit technology ” yellow journalism. there you will see, besides “ Intel ( gas constant ) Virtualization technology, ” whether your central processing unit support information technology oregon not. besides, you can see whether your central processing unit back the strain page table ( EPT ), besides “ Intel VT-x with extend page Tables. ” see human body five .