I showed the use, effects and software QEMU virtual machine performance, but also analyzes the different users different quest for virtual machines. But regardless of the desktop user or enterprise users, the search for virtual machine software have in common, that is performance. QEMU is a powerful virtual machine software, which can be completely in the form of software to simulate a complete all required computer hardware, and even simulate different hardware architectures, virtual hardware in the above, you can install the full operating system.
Obviously, this entirely in software in the form of analog hardware, although powerful, but the performance is difficult to meet the needs of users. Simulate the physical performance and hardware performance compared to hardware, is bound to be greatly reduced. In order to improve the performance of virtual machine software developers recount. The most common way is the main operating system to open a hole in the kernel module, through the hole in the virtual machine operating mapped directly to the physical hardware, thereby improving virtual machines running operating system performance.
KVM which is a typical representative of this acceleration mode. In the community, we often comparable to the KVM and Xen, but in fact they are completely different. As can be seen from the chart, use the kernel module to accelerate this mode, the host operating system still dominates, but the kernel module to open a hole in the main operating system, used to connect the virtual and physical hardware to virtual machines to accelerate, but virtual machine guest operating system is still severely limited. This mode is more suitable for desktop users use their primary operating system is still the main battlefield, whether it is work or play games, completed by the host operating system, the guest operating system is on-demand. As Xen, is entirely different ideas, more suitable for enterprise-class users, desktop users do not easily touch, and the specific contents of an I repeat.
In fact, this kernel module VirtualBox also take accelerated mode. The reason I say that is because when you install VirtualBox, it will require the installation of DKMS.
Familiar with Linux know, DKMS is to facilitate user management kernel modules exist, people who are not familiar with DKMS Google it can also get an idea. VirtualBox on specific use of the content, I repeat that next. This is a major stresses KVM.
KVM and QEMU are complementary, QEMU KVM kernel module can be used to accelerate the use of QEMU and KVM need to run virtual machines. You can see from the chart, if you are using Ubuntu's package management software installed KVM, in fact, is to install qemu-kvm. The qemu-kvm is not what a very complex package that contains only a small amount of several files
Check with the man the order to its documentation, discovery file qemu-kvm package contains not only rare, and it's also just the executable file kvm qemu-system-x86_64 command a simple package
So the question is, what kvm kernel module which is provided by the bag? In fact, since the beginning of Linux 2.6, kvm it has been added to the kernel. If I have to find out the kvm kernel module kvm.ko which is provided by the package, you can use the following command to look at
I write to you, we can already see that KVM is very simple to use up. Now, I use the KVM to run once on a WinXP operating system installed, operational efficiency through experience after KVM QEMU acceleration. Use the following command to run using KVM QEMU acceleration
As can be seen, the use of accelerated KVM virtual machine WinXP run a lot faster, boot it only took 34 seconds. I will adjust the resolution of 1366 * 768, the graphical interface is running very smooth, whether it is to open the IE browser or Office software, no problems, no longer CPU usage soared to 100% of the cases did not appear. If ps -ef | grep qemu command to check and found the command to run kvm or qemu-system-x86_64 program, but added -enable-kvm parameters
In addition, for desktop users, there is a user-friendly graphical interface is also very important. Although QEMU and KVM their own without the graphical interface virtual machine manager, but we can use third-party software, such as virt-manager. Only you need to use sudo apt-get install virt-manager to install the software. The software relies on libvirt, it will be automatically installed during the installation process. Running virt-manager of the effect of the following figure, note that you must use sudo to run because the software requires superuser privileges
The software automatically recognizes the system virtual machine environment is QEMU + KVM or Xen. Create a new virtual machine, due to the previously installed a WinXP system, so I chose to import an existing hard disk image. After the next point, the following interface
This step is nothing to say, and then click Next
Here you can set network options. If you check "before installing a custom configuration", it is also possible to further customize the hardware
We can see the virtual machine supports all types of virtual cards, here, of course I chose VMVGA, because I used to use VMWare, know the operating system under VMWare virtual graphics settings runs are no problem. Of course, other options you can try, but in the virtual operating system, you need to install the appropriate drivers.
Finally, the effect of the virtual machine running
You can see that the program provides an interface has a very rich menu, function is very powerful, and can even send key combination to the virtual machine operating system.