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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How to efficiently share host's folder with KVM guests?

I am configuring the service which stores plenty of files uploaded by nginx in /srv/storage dir on host system. These files are processed by worker KVM guests which may create new files or assign extended attributes to existing ones. Files are never…
gertas
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Qemu TRIM and discard on a physical SSD device

I am running Windows 7 in a Qemu/KVM with a passed through GPU which I use for work-related stuff. I recently got fed up by it's unprecedented slowness due to it running off a mechanical drive, so I added an SSD to my box to 'give' to my…
nohupper
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How to speed up QEMU on Windows host?

We want to run our Ubuntu 64bit web server virtualized/emulated on a Windows 64bit host. Intended use is to distribute the VM to customers who might not have "elevated" or "admin" rights on the Windows machine. The system should be portable, i.e.…
Martin Heide
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Can I run a KVM guest with a btrfs subvolume as file system?

I want to run a virtualized Debian stable KVM guest on a Debian stable host (to run untrusted stuff like Skype, Flash or eclipse with third-party plugins). Naturally host and guest will have many files in common and it would be nice to make us of…
Thomas Koch
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Filesystem passthrough functionality in Centos 6.2?

I have a CentOS 6.3 machine currently running 2 virtualized CentOS 6.2 machines via KVM/QEMU/Libvirt. I'm trying to setup filesystem passthrough between the guests and the host. However the option is grayed out in the Virtualization Manager with the…
mm118
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Monitor VM's resources (CPU, RAM etc)

I'm testing Openstack and i'd like to know how can i find out about resource utilization inside instances (Virtual Machines). Openstack uses kvm, qemu and libvirt in my testing environment. Is there any way to get those stats without logging in…
Simon
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QEMU-KVM Linux virtualization on the command line

I recently discovered that qemu-kvm has a very promising -curses option that, instead of starting an X window, will show a nice ncurses output from the guest suitable for managing a Linux guest from the command line (or, more satisfyingly, within a…
malloc47
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TCP/IP performance tuning under KVM/Qemu

With more and more companies switching to public cloud services, I'm curious what you guys' thoughts are on TCP/IP tuning in the cloud. Is it worth bothering with? Given that you don't have access to the host-server, you're somewhat limited I…
vpetersson
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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:…
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Convert qemu syntax to virt-install or virsh xml

I have parameters for qemu-system-x86_64, which attach unix socket as interface into VM: qemu-system-x86_64 -chardev socket,id=char1,path=/tmp/sock0,server \ -netdev type=vhost-user,id=hostnet1,chardev=char1 \ -device…
UsCr
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QEMU and serial ports on the guest OS

Has anyone successfully managed to run a Guest OS in QEMU/KVM where the guest has full access to the Hosts serial port(s), be it /dev/ttyS0, COM1, or a virtual serial port provided by the Host. It seems the documentation on -chardev, -serial, etc.…
joho
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qemu running in ssh: how to exit?

I am connected via SSH to a terminal server. On this server I am using qemu-system-x86_64 ... -curses to run a Command Line based operating system. How can I terminate the virtual machine? At the moment, the only option I have, is to open a second…
Daniel Marschall
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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…
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VNC faster than Spice for remote access to KVM guest?

Having used RDP before, I'm not exactly thrilled with the performance I am seeing from VNC to my KVM virtual machines. The KVM host is Ubuntu 12.04 server x64. I've read that Spice is faster, and so after considerable bumbling around, I got it to…
Dave
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