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Questions tagged [qemu]

QEMU stands for "Quick EMUlator" and is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port to new host CPU architectures.

QEMU has two operating modes:

  • User mode emulation

In this mode QEMU runs single Linux or Darwin/Mac OS X programs that were compiled for a different CPU. System calls are thunked for endianness and for 32/64 bit mismatches. Fast cross-compilation and cross-debugging are the main targets for user-mode emulation.

  • Computer emulation

In this mode QEMU emulates a full computer system, including peripherals. It can be used to provide virtual hosting of several virtual computers on a single computer. QEMU can boot many guest operating systems, including Linux, Solaris, Microsoft Windows, DOS, and BSD 1; it supports emulating several hardware platforms, including x86, x86-64, ARM, Alpha, ETRAX CRIS, MIPS, MicroBlaze, PowerPC and SPARC.

Source: wikipedia

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host port forward with qemu through libvirt in user-mode networking

I'm having trouble editing my libvirt's host-xml to make qemu forward TCP connections to the guest. This questions linked to a blog post which recommended adding -redir to the Qemu command line. But that stopped working as of recently. error:…
Frederick Nord
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How to "really" reduce the size of KVM VMs images?

I've spent many hours searching the web about how to shrink KVM virtual disk images, especially for Windows guests, with no luck. All I've found is to zeroize the VM free space, defrag the virtual disk (from Windows), and then run qemu-img convert…
romu
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Prevent hijacking IPs in KVM/libvirt

How can I prevent a VM user/client from accessing IP addresses he doesn't own but are routed over the same bridge on KVM/Libvirt? IP addresses are routed to a cisco switch vLan consisting of a /24 254 usable addresses eg. 105.100.1.0/24. Here is an…
user3400748
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Accessing the partitions on an LVM volume

Suppose you have an LVM volume /dev/vg0/mylv. You have presented this as a virtual disk to a virtualised or emulated guest system. During installation the guest system sees it as /dev/sda and partitions it into /dev/sda{1,2,5,6} and completes the…
projix
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kvm and qemu host: Is there a limit for max CPUs (Ubuntu 10.04)?

Today we encountered a really strange behaviour on two identical kvm and qemu hosts (Dell R910). The host systems each have 4 x 10 Cores, which means that 40 physical cores are displayed as 80 within the operating system (Ubuntu Linux 10.04 64 Bit,…
PythonLearner
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Maximizing throughput of virtual file systems

I've been using a QEMU system to build software. The problem I've been having is that the system seems to suffer from extremely slow disk access. This is not necessarily a problem as it's not really a time-intensive operation, but I'd like to have…
amphetamachine
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KVM: What is stored in var/lib/libvirt/qemu

My Question is "What is stored in the /var/lib/libvirt/qemu folder?" Is this used as somekind of backup folder ? Backgroundinformation: I have a Debian Server with a running KVM installation(+libvirt) and ~ 15 running VMs. And i want to understand…
KVMUser123
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How do I mount an .iso with another (live CD) .iso?

I want to: Place the .iso of a live CD in a directory. Use qemu (kvm or kqemu) to run the .iso Put a 2nd live CD .iso in the same directory. Have the 1st live CD mount the 2nd .iso. Say, I have 2 .iso files in the same directory, how can I emulate…
None
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QCOW2 virtual size lowering

I'm trying to get the virtual size of a qcow2 container down so that it can fit in a openstack flavor with 10GB disk. root@node-10:~# qemu-img info zztop.qcow image: zztop.qcow file format: qcow2 virtual size: 80G (85899345920 bytes) disk size:…
Duncan Fairley
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Libvirt guest destroyed after shutdown

I have created a VM withLibvirt and when I shut it down whether forcefully or with ACPI, it gets deleted. I create it: deneme2 2097152 1 hvm …
Mustafa
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QEMU USB passthrough is not working

I stuck at getting USB passthrough working with Windows 8.1 guest OS on Ubuntu Server 14.04. I started by installing qemu using the Ubuntu Documentation (https://help.ubuntu.com/community/KVM). The USB device (Datev mIdentity) was recognized by the…
ya man
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How to configure and use qemu-guest-agent in Ubuntu 12.04? My main aim is to get the IP address of guest VM from Host machine

In the documentation it is not very clear that how to install and use qemu-guest-agent in Ubuntu 12.04. So can anyone help me out ? http://wiki.libvirt.org/page/Qemu_guest_agent It is a daemon program running inside the domain which is supposed to…
A-B
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Migrating physical machine to KVM

I have a fairly old debian machine that I need to migrate to KVM-Qemu. What I started is to make a tarball of the root filesystem: tar -cpf rootfs.tar --exclude='dev/*' --exclude='proc/*' --exclude='sys/*' --exclude='home/*' / scp tar file to a…
qemu55
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Any way to convert qcow2 to ovf?

In our application we are downloading a qcow2 image and after that we are supposed to import that as OVF. So any way to convert qcow2 --> OVF or qcow2 --> vmdk(using qemu-img convert) --> ovf .
Reuben
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Why I can't save network changes with virsh?

I am trying to add fixed address to specific virtual host, therefor I closed virtual machine and used sudo virsh net-edit somenet. After adding line I saved and quit.…
wk.
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