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.

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52 views

How to get internet/networking on QEMU for OpenWrt under Windows?

I would like to run a Internet-capable OpenWrt-Box on a Windows10 Machine using QEMU. I have tried this command: "c:\Program Files\qemu\qemu-system-aarch64.exe" -m 1024 -smp 2 -cpu cortex-...
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Share data via QEMU and NFS with Mac host (OSX Catalina) and Linux Guest (Ubuntu 20.04)

Story so far We recently migrated from Linux laptops to Macbook Pro laptops (company IT no longer supports native Linux laptops with VPN, so it's all Macbook/OSX devices for us). However, all of our ...
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can't initialize iptables table 'nat' under qemu

I am facing an issue while starting docker inside s390x container under qemu on Ubuntu 18.04 host running on amd64. Steps followed (On amd64 host): docker run --rm --privileged multiarch/qemu-user-...
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How to enable zstd for your qcow2 files

In QEMU 5.1 zstd compression of your qcow2 files was introduced. But it's not described in the manual for qemu-img. How do you enable it?
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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 ...
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DHCP not working for bridged QEMU virtual machine

Environment: A router with DHCP server. This router manages a subnet of 172.16.0.1/16 A host with Ubuntu 20.04 installed, and it has a NIC named eno0. A QEMU virtual machine running on host. Purpose:...
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NATing through a vpn with libvirt

I installed a server with libvirt, and I've created a test VM. When I use the default network for it's interface, it gets a private IP and the NATing seems to work fine. I installed OpenVPN, so I have ...
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3answers
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does KVM raw images support preallocation?

I was trying to create a raw image with this command: qemu-img create -f raw -o size=200G,preallocation=metadata file.img but seem that it raw images doesn't support preallocation. if so why there ...
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How to create Bridged connection for Qemu/KVM with Wifi?

I want to create a bridged connection in qemu/kvm. What I want to do is connect the wifi to a bridge (as a slave), then use this bridge to provide network access to the VM. Using nmtui, I deleted my ...
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Ways to access qemu monitor inside guest

What are the ways of accessing qemu monitor inside the guest i.e VM other than pressing Ctrl+Alt+2 buttons? Is there any way we can access the qemu monitor using telnet from the guest?
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KVM-QEMU Windows Guest Memory Speed

How to speed up memory in Windows guest running on KVM-QEMU hypervisor? The memory speed differs between Ubuntu guest and Windows 2016 Server on the same node quite a lot. Same benchmark tool counts ...
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Error while executing custom command of qemu-guest-agent

I am trying to execute a simple hello-world custom command of qemu-guest-agent but getting the below error while building the qemu. qga/qapi-generated/qga-qapi-commands.o: In function '...
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1answer
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QEMU Monitor via Remote Desktop

I want to access QEMU monitor from my Windows VM, but I have connected the Windows VM via RDP. When I press Ctrl+Alt+2 , the QEMU monitor is not opening. If I do the same when connected without RDP, ...
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Not able to start virtual machine/domain in KVM: Failed to get “write” lock

After host's restart, I'm not able to start virtual machine: user@server-1:~$ virsh start docker-1 error: Failed to start domain docker-1 error: internal error: process exited while connecting to ...
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1answer
539 views

QEMU and SPICE on Win 10 host

I am trying to run a Linux kernel based VM image (1) using QEMU on Windows 10 host. I have installed QEMU from https://qemu.weilnetz.de/w64/qemu-w64-setup-20190815.exe and SPICE client from https://...
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Debian Stuck at Booting from Hard Disk after installation on KVM

I'm trying to install Debian on Qemu-KVM on RouterOS v5.25 I tried : debian-10.8.0-i386-netinst.iso debian-8.11.0-i386-kde-CD-1.iso debian-live-9.0.0-i386-gnome.iso on disk image created using : qemu-...
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libvirt Windows 10 VM issue

I am running Manjaro KDE and I have managed to setup a Windows 10 VM with GPU passthrough for Windows things and it was working great until I noticed a weird behavior. When I try to reboot the VM, or ...
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Noop convert qcow2 image but keeps internal snapshots

I have a qcow2 image. The image size is 200 GB, but the actual use is only 30 GB. I'm using qemu-img convert -O qcow2 source.qcow2 shrunk.qcow2 to removes sparse space and the images shrinks correctly ...
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EL6/KVM guest dies with “pthread_create failed: Resource temporarily unavailable”

I've got a CentOS 6.5 x86-64 KVM server with a bunch of guest VMs of different breeds, mostly EL5 and EL6. However one and only one of them keeps crashing every couple of days with: pthread_create ...
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How to create virtual networks by using libvirt?

I have installed qemu/kvm and have tried to create some virtual machines and network them together. What I would like to achieve is 2-3 virtual machines in their own private network (e.g. 10.0.0.0/24)...
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Cannot Create QEMU Socket Networking in Windows Host using Multicast Fails with Unknown Error

I am trying to create a simulated VLAN using socket networking, and the only way to connect multiple VMs in one network in QEMU using socket networking is by using the multicast mcast option of the ...
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1answer
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Nested Virtualization KVM: entry failed, hardware error 0x7

I have a VM on a host and want to create another VM within the existing VM (nested). Host: opensuse Tumbleweed, kernel 4.19.7, 96 CPUS Intel-Xeon, 256GB RAM (nested virt enabled in kvm) L1 VM: ...
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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 ...
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kvm virtualization, slow io in windows guest (with virtio drivers) on ubuntu host and HP 360 Server with P440 RAID controller

Problem: Very slow IO in Windows Guest vs Host Hardware: HP 360 G9, 2 x 10 cores Xeon CPU, 128GB Ram, 4 x 4TB SAS HDD, Raid 10, P440 Controller (with 2GB cache and battery) Host: Ubuntu 20.04 Server, ...
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2k views

Ubuntu + bridge +qemu + tap + virtio dropping packets

I've got what I think is the standard qemu bridge/ubuntu tap interfaces set up running variety of VMs on my Ubuntu host. All the VMs I'm having trouble with are Windows images. I have researched this ...
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What triggers a “*** Guest State ***” register dump from the linux kernel?

Prefix: There is no kernel crash. Something, rarely, is triggering Guest State, Host State, Control State register and other debug variable dump to kernel log. The system in question is running many ...
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1answer
2k views

Signaling KVM/QEMU VM to quiesce, preparing for live backup

Assume a KVM/QEMU VM, which uses qcow/qcow2 as the image format for virtual disks. Backup is (to be) done on the VM host. As far as my current understanding goes is that while we can create backups ...
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1answer
1k views

Convert virtual disk image to physical disk?

I'm trying to use QEmu for Windows to convert a virtual disk image to a physical SSD. But I'm not sure about the syntax for the output_filename parameter. Here's what I tried: qemu-img convert -p "D:\...
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3answers
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Difference between KVM and QEMU

I have been reading about KVM and Qemu for sometime. As of now I have a clear understanding of what they do. KVM supports hardware virtualization to provide near native performance to the Guest ...
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1answer
1k views

QEMU Network bridging for having a public IP

I simply want that my QEMU VMs have a public IP so I can run multiple servers in the same machine. I've read a lot of wikis, guides, tutorials, forum threads and anything related to this but still no ...
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3answers
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KVM guest cannot write to 9p share owned by non-root

I am aiming to set up full write access to a 9p share for a KVM guest. Both host and guest have the same users/groups with the same IDs. Both host and guest should be able to write to the share using ...
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1answer
342 views

Multicast not working on macvtap device

I have a problem with my virtual network and IPv6 network discovery (multicast traffic). (The setup might seem a little bit involved and I don't remember the exact reasons for every design decision. ...
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101 views

Ubuntu Installation on Qemu/KVM Black Screen

I'm trying to install Ubuntu or higher on KVM. I have tried installing 14.04.6 LTS / 16.04.7 LTS and 18.04.5 LTS First i create Qemu Disk Image : qemu-img.exe create -f raw hdd.img 5G and when i boot ...
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Correct SELinux labels for a kvm/qemu user session VM shared folder

I am trying to set up a shared folder using the 9p protocol for a kvm/qemu VM that runs on the user session (so the qemu process runs as me, not as root). Mounting the shared folder in guest works ...
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1answer
1k views

unable to ssh into local qemu instance via port forward

I am trying to build a custom Ubuntu (ISO built from bionic - 18.04.2) qcow2 image via packer. This fails in the step where packer tries to SSH to the instance via port forward. I can see from VNC ...
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2answers
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Read/write access for passthrough (9p) filesystems with libvirt/qemu?

I have recently started experimenting with the support for passthrough filesystems in recent versions of KVM/QEMU/libvirt. Making the filesystems available for read access has "just worked", but I'm ...
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1answer
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Can you start a getty on /dev/pts/x ? Want a serial connection between my Linux KVM server host and Windows Guest

Here's what I have going on: I have a Debian server running several services in Docker and a couple in KVM. One of the KVM hosts is a Windows 10 VM that I actually use as a desktop by using PCI ...
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1answer
2k views

qemu/virt-manager no permisson on shared folder

I have a strange problem. Iam trying to create a shared folder via the add-hardware->filesystem option. For Type and Modus i choose Passtrought and for Driver Path. The Source Path is /free and target ...
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Old KVM Guest not starting after reboot

I have a bunch of Virtual Machines in a Ubuntu 18 Guest machine. Until recently they have all been working without any problem. However after I restartet one of the Guests(also Ubuntu) it is now not ...
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1answer
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boot from cdrom !! kvm -machine pc-i440fx-2.1 [closed]

I am trying to follow the instructions in the following article https://docs.j7k6.org/vmware-esxi-hetzner-install-kvm-linux/ I start the VM by the following command kvm -machine pc-i440fx-2.1 \ -cpu ...
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qemu does not give by-id symlinks for drives by UUID in linux guest

I am trying to get my drive to show up in QEMU guest virtual Linux machine. desired behavior: $ ls /dev/disk/by-id/ ata-CT1000MX500SSD4_XXXXXX Current behavior returns nothing: $ ls /dev/disk/by-id/ ...
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1answer
136 views

Arch Linux - QEMU override System Manufacturer on Windows 10

I've fully virtualized a VM with windows 10 on QEMU and had to do host-passthrough in order for it to work. Because there's no way to set SMBIOS to reflect the host, I want to know if there's any way ...
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1answer
2k views

QEMU Ubuntu Server 20.04 Initramfs write error

I created a QEMU virtual machine intending to install Ubuntu Server 20.04. The host is a Proxmox 6.x Debian system. The virtual machine parameters are: 2 CPU cores, 1 socket 512 MB ram, ballooning ...
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105 views

Is it possible to have both spice or sdl and vfio gpu pass-through together, accelerated streaming started from boot?

There are various ways to get the screen from a running qemu virtual machine: vfio-gpu-pt (display port to monitor) looking glass spice virgl sdl sdl2 gtk (qemu from source) AMT IPMI KVM(Keyboard ...
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1answer
114 views

QEMU / KVM - Dedicated 802.1q VLAN for each VM - Communication only via router

I have a Linux firewall router (dedicated machine) with multiple ethN interfaces (my "big firewall"). All forwarded traffic is filtered by a set of iptables rules (default policy DROP). ...
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1answer
4k views

Host to guest connection via SSH (using qemu vm)

I am having trouble to enable a host-to-guest communication using qemu VMs. The goal is to connect via SSH from the host to the guest VM. I have the following setting: host: local access to SSH ...
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1answer
2k views

How to start a new instance of QEMU based on the same image and snapshot?

I have a QEMU image (qcow2) with a snapshot stored in it. Right now I'm using libvirt to start it. However, I want to be able to run more than one instance of the same image snapshot. I guess I can ...
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24 views

Can I customize all my operating systems that I will install on kvm/qemu with Virt-customize?

For my private cloud provider, I want to create a virtual machine from the operating system iso I want using kvm/qemu (since I was looking for an alternative to cloud-init, I chose to customize it ...
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99 views

How to enable nested virtualization in order to use VirtualBox inside of a KVM virtual machine?

We have a KVM hypervisor (L0, AMD, Kernel: Linux level0kvmhypervisor 4.19.0-12-amd64 #1 SMP Debian 4.19.152-1 (2020-10-18) x86_64 GNU/Linux), which runs a virtual machine that I would like to use as a ...
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1answer
2k views

QEMU versatilepb default network adapter

I'm using qemu to emulate a raspberry pi. I'm starting qemu like this: qemu-system-arm -kernel ./qemu-rpi-kernel/kernel-qemu-4.1.13-jessie \ -cpu arm1176 -m 256 -M versatilepb \ -append "...

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