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Ubuntu in how to build Kvm environment, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain for you in detail, people with this need can come to learn, I hope you can gain something.

1. Configuration of hardware system

In x86-64 processors, the necessary hardware virtualization extensions for KVM are Intel Virtualization Technology (Intel VT) and AMD AMD-V technology. First of all, the processor (CPU) has to support VT technology in hardware, and turn on its function in BIOS before KVM can use it. Currently, most popular servers and some desktop processors have BIOS turned on VT by default.

In Linux systems, you can check the CPU feature flag (flags) in the / proc/cpuinfo file to see if CPU supports hardware virtualization. On x86 and x86-64 platforms, the Intel series CPU support virtualization flag is "vmx", and the AMD series CPU flag is "svm", so you can view the "vmx" or "svm" flag with the following command line.

Grep-E'(vmx | svm)'/ proc/cpuinfo2. Install the host Linux system

KVM is a kernel-based virtualization technology, and to run a KVM virtualized environment, it is necessary to install a host (Host) of the Linux operating system. The following will use ubuntu18.04 as an example for installation.

3. Compile and install KVM3.1 download source code

Download Kvm

Url: https://git.kernel.org/pub/scm/virt/kvm/kvm.git/

Version: linux-4.16.tar.gz

3.2 Config Kvm

Use visual configuration options, otherwise the 9k + configuration will make you crash.

Make menuconfig

If an error occurs: Unable to find the ncurses libraries

Sudo apt-get install ncurses-dev

After selecting Virtualization, enter it for detailed configuration, including selecting KVM, processor support, and so on.

CONFIG_HAVE_KVM=y CONFIG_HAVE_KVM_IRQCHIP=y CONFIG_HAVE_KVM_EVENTFD=y CONFIG_KVM_APIC_ARCHITECTURE=y CONFIG_KVM_MMIO=y CONFIG_KVM_ASYNC_PF=y CONFIG_HAVE_KVM_MSI=y CONFIG_VIRTUALIZATION=y CONFIG_KVM=m CONFIG_KVM_INTEL=m # CONFIG_KVM_AMD is not set CONFIG_KVM_MMU_AUDIT=y

Ensure that the above configuration related to Kvm is correct.

3.3 Compile Kvm

It needs to go through three steps: compiling kernel, compiling bzImage and compiling module.

Compile kernel

Make vmlinux-j 20

The-j parameter means that 20 processes are used for compilation, which is not required.

Error encountered: scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory

Sudo apt install libssl-dev

Compile bzImage

Make bzImage

Compile module

Make modules-j 20

3.4 Install Kvm

The installation of KVM includes two steps: the installation of module and the installation of kernel and initramfs.

Install module

Make modules_install

The above command installs the compiled module into the appropriate directory, and module is installed into the / lib/modules/$kernel_version/kernel directory by default.

Error Makefile:934: "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev,libelf-devel or elfutils-libelf-devel" temporarily removes this configuration from the configuration file:

# CONFIG_STACK_VALIDATION is not set

After installing module, you can check the appropriate installation path and see that the kvm module has also been installed.

Ls-1 / lib/modules/4.15.0/kernel/ ls-1 / lib/modules/4.15.0/kernel/arch/x86/kvm/

Install kernel and initramfs

Make install

Error: gzip: stdout: No space left on device cleans / boot partition or resizes / boot partition.

Ls-l / boot/

As can be seen from the above command, the files needed for kernel startup, such as vmlinuz and initramfs, are generated in the / boot directory.

Cat / boot/grub/grub.cfg

As you can see from the above command, after running make install, a grub option is automatically added to the grub configuration file (such as: / boot/grub/grub.cfg).

Restart the system and select the kernel boot you just compiled and installed for KVM.

In general, the kvm and kvm_intel modules are loaded by default when the system starts; if not, manually use the modprobe command to load the kvm and kvm_intel modules in turn.

# check whether to load lsmod | grep kvm # load modprobe kvm modprobe kvm_intel manually if not

Check / dev/kvm file

It is a control interface provided by the kvm kernel module for qemu-kvm programs in user space. It provides the simulation and actual hardware device environment needed by the client (Guest) operating system.

Ls-l / dev/kvm

4. Compile and install qemu-kvm

In addition to the kvm module in kernel space, QEMU is required in user space to simulate the required CPU and device models and to start client processes, so that there is a complete KVM runtime environment. Qemu-kvm is a branch of QEMU that has been modified and optimized specifically for KVM.

Download the qemu-kvm source code

Url: https://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git

Version: qemu-kvm-2.3.0.tar.gz

Configure qemu-kvm to run the configure file in the code repository directly for configuration.

. / configure

Error ERROR: pkg-config binary 'pkg-config' not found

Sudo apt install pkg-config

ERROR: zlib check failed Make sure to have the zlib libs and headers installed.

Sudo apt-get install zlib1g-dev

Error ERROR: glib-2.12 gthread-2.0 is required to compile QEMU

Sudo apt-get install libglib2.0-dev

ERROR: pixman > = 0.21.8 not present.

Apt-get install libpixman-1-dev

ERROR: DTC (libfdt) not present.

Apt-get install libfdt-dev

Compilation errors will still occur after correcting the above errors.

It is found that the version downloaded by kernel.org has not been updated for two years. Download the latest stable version from the official website:

Url: https://www.qemu.org/download/ version: 2.12.0

Make sure that the configuration is correct:

VNC support yes # usually needs to connect to KVM support yes # in the client through VNC, which is support for KVM

Compile qemu-kvm and directly make for installation:

Make-j 20

As you can see, finally, the qemu-system-x86_64 file is compiled and generated, which is our commonly used command line tool for qemu-kvm.

After installing qemu-kvm and compiling, run the make install command to install qemu-kvm.

The main tasks of the qemu-kvm installation process are as follows: create some directories of qemu, copy some configuration files to the corresponding directory, copy some firmware files (such as sgabios.bin, kvmvapic.bin) to the directory so that when the command line of qemu-kvm starts, you can find the corresponding firmware for the client to use, and copy keymaps to the appropriate directory to support various required keyboard types in the client. Copy qemu-system-x86_64, qemu-img and other executable programs to the corresponding directory.

Check the system status after qemu-kvm installation

Which qemu-system-x86_64 which qemu-img ls / usr/local/share/qemu/ ls / usr/local/share/qemu/keymaps/

Because qemu-kvm is a user-space program, you don't have to restart the system after installation, you can use qemu-kvm with command-line tools such as qemu-systemx86_64 and qemu-img.

5. Install the client

Create an image file, disk partition, etc., to store the client's system and files

Dd if=/dev/zero of=rhel6u3.img bs=1M count=40960

Start the client

Qemu-system-x86_64-usbdevice tablet-m 4096-smp 2-enable-kvm-boot order=cd-hda / home/micle/Proj/VirtDemo/win7sp1.img-cdrom / home/micle/Proj/VirtDemo/win7pro_sp1_x64_dvd_u_677031.iso

Install vncviewer and connect to the client

Sudo apt install vnc4server sudo apt install xvnc4viewer

Vncviewer ip:5900

Ctrl+Alt+2 switches to the QEMU monitor window

Some commands can be executed in the monitor window, such as the info kvm command to see if the current QEMU is using KVM. Ctrl+Alt+1 can switch back to the original window.

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