Re: [Qemu-discuss] Difference between qemu-kvm, qemu-system-x86_64, qemu-x86_64

[Jakob Bohm]

On 05/04/2016 05:40, Zhang Qiang wrote:

For new features, I recently updated qemu-kvm 1.5.3 to qemu 2.5.0, but I saw several qemu binaries, `/usr/local/bin/qemu-x86_64` and `/usr/local/bin/qemu-system-x86_64`. It seems `qemu-system-x86_64` is the emulator program, since libvirt won't recognize `qemu-x86_64`. Then what's qemu-x86_64 for?

qemu-cpuname is for running cpuname Linux programs under
Linux without starting an actual cpuname virtual machine.

Instead the program is run with the system configuration
of the host Linux.

And according to this qemu doc: http://wiki.qemu.org/KVM:

> qemu-kvm fork for x86 (deprecated, use upstream QEMU now)

It seems qemu is replacing qemu-kvm. But if qemu not qemu-kvm is used, is the guest CPU still provided by KVM? If not so, will the performance be worse?

qemu-system-x86_64 now takes an option to specify if
the virtual machine should be run using the KVM kernel
module or not.  In the past that option was only
available in the special qemu-kvm program.

See man qemu-system-x86_64 for the exact names options.

Enjoy

Jakob
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Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
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