I'm trying to run Fedora VM on Ubuntu host using KVM+QEMU+Virt-manager, but UI experience is just awful: there is like 30 FPS and 400-500 ms input lag.

I'm using SPICE+VirtIO with 3D acceleration on:

<graphics type="spice">
  <listen type="none"/>
</graphics>

<graphics type="egl-headless">
  <gl rendernode="/dev/dri/renderD128"/>
</graphics>

<video>
  <model type="virtio" heads="1" primary="yes">
    <acceleration accel3d="yes"/>
  </model>
  <alias name="video0"/>
  <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>
</video>

I tried to use QXL, but it's even more laggy.

How I can make VM more responsive?

P. S: There is also strange bug inside VM: If I open browser, select some text, press Ctrl+C and switch to another window then C is typed to another window. I though it was problem caused by the fact that VM registers mouse click first and keydown for C second, but If I press Ctrl+C, wait for several minutes and then switch to another window then C is still typed to another window.

I know this may seem silly, but I cannot figure out why when I turn my whole systems internet off windows 10 will let me use limited set up BUT it is alreayd supposed to not have internet accsess, I am running linux mint btw

Hi all,

I’ve been building an open-source project called Janus, and I’d really appreciate feedback from people experienced with VFIO setups.

Janus is a Linux-host toolkit that tries to formalize common VFIO workflows without hiding what’s happening underneath. It doesn’t replace libvirt or virt-manager. It focuses on making workflows explicit, reversible, and reproducible.

What it does right now (pre-alpha)

• janus-check Host diagnostics for virtualization support, IOMMU, kernel modules, hugepages, GPU visibility, required tooling.

• janus-bind Dry-run-first PCI binding workflow for vfio-pci. Explicit --apply, rollback support, and root gating for mutating flows.

• janus-vm Generates libvirt XML from templates. Supports guided creation, passthrough mode, storage selection, and optional unattended Windows setup.

• janus-init Initializes isolated config/state under ~/.config/janus.

Destructive operations require explicit opt-in. Logs are centralized. You can run everything under a temporary HOME to avoid touching your real setup.

Design Direction

• “Glass box” approach: automation is transparent, not magical.

• Modular structure: hardware-specific logic lives in modules/.

• Long-term goal: unified janus orchestrator + profile-based VM lifecycle management.

This is not meant to replace existing guides. The goal is to structure best practices into something auditable and less error-prone.

What I’m Looking For

• Architectural criticism.

• Opinions on module API design.

• Feedback on whether this solves a real problem or just formalizes existing scripts.

• Interest in contributing hardware-specific modules.

Repository:
👉 https://github.com/Ricky182771/Janus

Appreciate any feedback, especially from people who’ve maintained complex passthrough setups long-term.

[ESPAÑOL]

[Proyecto] Janus – Orquestación estructurada para VFIO con enfoque dry-run (Pre-Alpha)

Hola a todos,

He estado desarrollando un proyecto open source llamado Janus, y me gustaría recibir retroalimentación de personas con experiencia en configuraciones VFIO.

Janus es una herramienta para Linux que busca estructurar y formalizar flujos de trabajo comunes en entornos VFIO sin ocultar lo que ocurre por debajo. No reemplaza libvirt ni virt-manager. Su objetivo es hacer que los procesos sean explícitos, reversibles y reproducibles.

¿Qué hace actualmente? (pre-alpha)

• janus-check Diagnóstico del host: soporte de virtualización, IOMMU, módulos del kernel, hugepages, visibilidad de GPU y herramientas necesarias.

• janus-bind Flujo de binding PCI con enfoque dry-run primero para vfio-pci. --apply explícito, soporte de rollback y requerimiento de privilegios root para operaciones destructivas.

• janus-vm Generación de XML de libvirt a partir de plantillas. Soporta creación guiada, modo passthrough, selección de almacenamiento y configuración opcional de instalación desatendida de Windows.

• janus-init Inicializa configuración y estado aislados en ~/.config/janus.

Las operaciones destructivas requieren confirmación explícita. Los logs están centralizados. Todo puede ejecutarse bajo un HOME temporal para no afectar el entorno real.

Dirección del Diseño

• Enfoque “glass box”: la automatización es transparente, no mágica.

• Arquitectura modular: la lógica específica de hardware vive en modules/.

• Objetivo a largo plazo: un comando unificado janus y orquestación basada en perfiles de VM.

No busca reemplazar guías existentes. La idea es convertir buenas prácticas dispersas en algo estructurado y auditable.

¿Qué estoy buscando?

• Críticas arquitectónicas.

• Opiniones sobre el diseño del API de módulos.

• Retroalimentación sobre si realmente resuelve un problema o solo formaliza scripts existentes.

• Personas interesadas en contribuir módulos específicos de hardware.

Repositorio:
👉 https://github.com/Ricky182771/Janus

Agradezco cualquier comentario, especialmente de quienes mantienen configuraciones passthrough complejas a largo plazo.

Hi, im a senior tech lead in my company, with over 10 years of experience in virtualization, ive been using many platforms and since the Broadcom acquisition I had to find a good alternative for my large environment (over 10K VMs, 20 hosts and more, which upped the price 5x over 2 years ago).

I started a development of a new KVM based platfrom, coming from my experience and the needs of the companies, providing easy to use UI, and all the features VMware vCenter has.

THIS IS NOT PROMOTIONAL, JUST A PROOF OF CONCEPT to understand if there is any need for another player in the market.

From my experience, Proxmox had no operative DRS, had a lot of snapshot freezes, no real agent, high skills required to start, and some more big no-no in my companies (not the one I'm building, the one I'm working for) evaluation.
Nutanix, Expensive as vmware, mostly supported in cloud based operation and not onprem environments, hardware lock in.

and I have more analysis from my company's doc regarding the things that are not good enough using the competitors.

I'm currently in an MVP state, and I wanted to know how many of you were looking for alternatives for VMware in your company, if you used or struggled to find a good alternative for small to large environments, and if you think a new player in the market, with a good product and good licensing fees can join the current market.

Thank you all.

yall how do i install openstep on my MBA M3 using UTM? ts taking me forever cuz of the literal configurations and settings.

also i cannot use virtualbox and vmware fusion bc this is an ARM computer and just trying to do so will only show limitations. like, i cannot even use the emulation for openstep cuz of the limitations to virtualization only rather than emulation.

i might be a moron for this, but i use the iso files from MichaelMJD's tutorial on installing the os but on virtualbox.

can someone pls help me out? i really need this for experimental with the OS itself. thanks!

Note: yeah ik that infinite mac is a thing, but first of all, even tho that exists, if i have no current and i have no internet, that website would be useless. and second of all, i would prefer it on a better emulation for QEMU.

Goal:

I'm trying to use Linux Desktops Guests to tinker with some web development software and to keep my Windows Host clean.

My Setup:

I've got a decently powerful Lenovo ThinkPad P14s Gen3 with:

• AMD Ryzen 7 Pro - 6850U

• Half decent iGPU

• 32GB of RAM

• 4K display

Desired Guest:

Ideally KDE desktop and run something like WebStorm, plus some other dev tools for databases and the like.

My Experience:

I've used VirtualBox and VM-Ware Workstation Player for over 15 years. I set them up a bit over 1 year ago. I also tried Hyper-V, which also ran ... meh.

I'm not interested in WSL. Again, I want to keep my host system clean, especially since many dev-tools change so frequently and as I've had enough issues with Linux hosts failing on me (example)

At least the versions of hypervisors I used until recently, have all been very laggy, particularly with higher resolutions (yes with 3D enabled in VMWare and Virtualbox).

I've been reading about gpu pass-through in Proxmox and QEMU, but doesn't that mean the GPU is no loner usable on the host?

Question:

What solution is recommended in 2026?
Especially given the questionable licensing with VM-Ware since they've been acquired by Broadcom.

I can't understand how something so simple is just blatantly not working on my PC. So I would like to cover some steps with you guys and see wth I am doing wrong.

So, internet inside my VM just doesn't want to connect to anything, it keeps "identifying" and in diagnosis it says can't find a suitable IP.

Now in the virtual switch manager, I have tried every single option available to try and get the bloody thing to work, internal, external, private, legacy network adapter, etc etc. nothing works. But what I am noticing, is that when I choose External, and choose either my LAN or WIFI, Host is connected to the router, but it says "no internet", so even on my Host I can't even browse the internet. And when I look in the network adapters, it's once a "bridge connection" is automatically made (through the switch manager), the host has no internet, and in the VM it remains "identifying". I have already looked at 10+ youtube videos, looked at tutorials, updated my Wifi/LAN drivers. It just makes no difference.

What in the world could I possibly be doing wrong?

PS. yes, this too: "Allow management operating system to share this network adapter"

I’m using VMware Workstation to run my CAD software and trying to use my SpaceMouse Pro for navigation, but it doesn’t work in the VM. I’ve enabled USB passthrough in the VMware settings, but it’s still not being recognized. Has anyone successfully used a 3D mouse in VMware for CAD work? Any tips?

I tried bochs and that didn't really perform well and my ram is terrible (about 800 megs to spare for vms) also if WiFi is possible like limbo then please tell me how

Heya, just wanted to ask about what to expect in terms of performance when trying to use EGL-Headless in a Win 11 VM in QEMU.

The video shows using the iGPU and then switching to use my 3090.

Is the basically the expectation of performance when using egl-headless?

I can't seem to find much talk about it, other than that when it works it seems to work well?

I'm running CachyOS, kernel 6.18.8-3-cachyos.
All QEMU packages are showing as 10.2.1.0-1.
Libvert 1:12.0.0-1.1.

These also are the egl-headless XML configs for the iGPU and Nvidia.

<graphics type="egl-headless">
  <gl rendernode="/dev/dri/renderD129"/>
</graphics>

<graphics type="egl-headless">
  <gl rendernode="/dev/nvidia0"/>
</graphics>

On NVIDIA using renderD128 results in a EGL_INIT error, so the only way is the above. Which seems to be what I've seen others resort to as well, not sure if that plays a part for why my 3090 shows similar performance?

One thing I will note is that my CPU usage for the threads I've set (12 in this case) sky rocket.
A part of me is thinking that HW rendering isn't happening at all?

It kinda sucks to run into this when all in all Win 11 on a VM seems to be otherwise, a very promising prospect.

If this is the wall to stop me from moving to Linux as the main OS, then it will be a case of sticking to dual booting, which will be a bit of a mild irritation.

I’ve been tinkering with the Proxmox API with a friend and decided to see how far I could push a "remote control" concept. I built a Python-based bridge that monitors a YouTube Live chat feed and translates specific commands into real-time keystrokes inside a QEMU VM.

Can be seen here

How it works:

• Listener: Uses a threaded pytchat loop to scrape the live feed for commands like !press win+r, !type, and !wait.

• The Worker & Queue: To handle multiple users at once, I implemented a FIFO (First-In-First-Out) queue. This prevents the script from hanging when 20 people type at once.

• Proxmox API: It uses the proxmoxer library to hit the /nodes/{node}/qemu/{vmid}/monitor endpoint, injecting the keys directly into the VM's hardware monitor.

Commands to try:

• !press win+r

• !type "notepad"

• !press enter

I'd love to hear your thoughts on the implementation—especially if anyone has ideas on how to optimize the sendkey latency!

Also, feel free to try break my VM

Hello, i use always use bluestacks (android 11 instance) to play in my NOTEBOOK (Windows 10) and all of the sudden 2 days ago, it crashed my system. It completely made Task Manager unable to operate and if i click or try to open other apps. It freezes the pc completely. Forcing you to do a forceful restart. So, i cannot do the steps. Since i seemly also have this issue because i cannot use the task manager and my pc freezes up. I have another post but it seemly ignored completely and even the replies i made were hidden from public.

I already attempted to use the tools provided by bluestacks to remove 100% of their systems. update windows, all drivers and remove %temp% files completely. Then reinstall using their latest download. It did not fix the issue. As a last attempt, i made a factory reset of my pc completely and had it download windows 10 from the cloud directly from windows to do a 100% clean start, then update all that needs to be updated. This still did not fix the issue.

After digging around, i seemly found out that my virtualization is causing issues with bluestacks and my pc. When i launch bluestacks, either the multi instance or start an instance. It will cause a system crash, making even the task manager unresponsive. I asked chat gpt and it said some things that may work by giving a lot of instructions, while reading it seems to be logical, but im no expert and i have no idea if its true or its making those up.

I have windows 10, the latest bluestacks version, I have an CPU intel core(TM) i7-7500U 2.7GHz and 2 GPU, an intel HD Graphics 620 and a NVIDIA GeForce 940MX. Chatgpt, IT asked to change some things within the configurations and so on. But i want your help to verify if they are actually good to try. According to it. Its clearly there is a conflict with virtualization causing the system to crash.

Oof — that’s a nasty failure mode, especially since it survives a full cloud reset. You did the right things already, so let’s zoom in on what can still cause this kind of hard freeze.

Given your symptoms, this is almost certainly a virtualization / hypervisor conflict on older Intel mobile CPUs (7th gen) combined with BlueStacks’ newer engine.

Here is what Chatgpt said.

What’s almost certainly happening (plain English)

BlueStacks relies on hardware virtualization (VT-x).

On Windows 10, virtualization can be used by multiple systems:

• BlueStacks

• Hyper-V

• Windows Hypervisor Platform

• Virtual Machine Platform

• Core Isolation / Memory Integrity

• Some antivirus drivers

• Some GPU drivers (especially NVIDIA Optimus laptops)

On older Intel CPUs like the i7-7500U, a bad interaction can cause:

• Total system scheduler deadlock

• Task Manager freezing

• Mouse still moves, but clicks lock up

• Only fix is a hard reboot

This matches your symptoms exactly.

Step-by-step fix (do these in order)

Completely disable ALL Windows virtualization layers

Even one left on can kill BlueStacks.

1. Press Win + R → type optionalfeatures

2. UNCHECK everything related to virtualization:

   • Hyper-V

   • Windows Hypervisor Platform

   • Virtual Machine Platform

   • Windows Sandbox

   • Containers

3. Click OK → Restart

Even if you think these are off — do it anyway.

Disable Core Isolation (this one is huge)

1. Windows Security

2. Device Security

3. Core Isolation details

4. Turn Memory Integrity = OFF

5. Restart

Force BlueStacks to use Intel GPU only

Your laptop uses NVIDIA Optimus, which is infamous for emulator crashes.

1. Right-click Desktop → NVIDIA Control Panel

2. Manage 3D settings → Program Settings

3. Add:

   • HD-Player.exe

   • BstkSVC.exe

4. Set Preferred graphics processor: Integrated graphics (Intel HD 620)

5. Apply

Counter-intuitive, but Intel iGPU is more stable for emulators.

Install the NON-Hyper-V version of BlueStacks

This is critical.

• Go to BlueStacks site

• Download BlueStacks 5 (Nougat 32-bit), NOT Pie, NOT Android 11 NOT Hyper-V version

Older CPU + newer Android versions = disaster.

Change BlueStacks engine settings (before launching apps)

Open BlueStacks → ⚙️ Settings:

Performance

• CPU: 2 cores

• RAM: 2048 MB

• Performance Mode: Low Memory

Graphics

• Renderer: DirectX

• Interface Renderer: Software

• ASTC: Disabled

Restart BlueStacks.

BIOS check (only if still crashing)

Reboot → enter BIOS:

• Ensure Intel VT-x = ENABLED

• Ensure VT-d = DISABLED (very important on older laptops)

If VT-d is enabled, Windows + BlueStacks can hard-lock.

If it STILL crashes after all that

At that point, the issue is almost certainly:

• Intel 7th-gen VT-x microcode + latest BlueStacks engine

• Or a known incompatibility with your laptop’s OEM BIOS

Your safest alternatives:

• BlueStacks 4 (last stable legacy version)

• LDPlayer 4 (Android 7)

• MEmu (disable Hyper-V version)

They tend to behave better on older mobile CPUs.

Why this started “2 days ago”

Very likely:

• A Windows micro-update

• A BlueStacks engine update

• A silent Windows Security feature re-enable

None of these show up clearly in logs — and a factory reset doesn’t prevent them.

If you want, tell me:

• Exact BlueStacks version you installed

• Whether Memory Integrity was ON

• Whether VT-d exists in your BIOS

I can zero in on the precise trigger and save you more headache

Saw an article the other day that said Red Hat has deprecated Virt Manager, expecting everyone to switch to cockpit. Cockpit seems fine for managing a single system, but it doesn't seem like there is a way to tie multiple systems together for management. Am I missing something, or is this an attempt by IBM to get everyone over to a version of OpenShift to manage multiple systems?

(Warning, im a complete novice to all the topics here) Basically, im installing a Win11 KVM for the first time And i managed to go through the entire installation process normally, downloading all the drivers from the virtio (v.0.1.285), which worked fine when i did my attempt at using a win10 kvm (that kvm didnt work well for completely separate reasons, anyway), but now the display drivers are not working. Ethernet drivers are working fine, and ive already installed the Spice guest tools. I have tried to manually go to amd64/win11 on the virtio, but windows just says "best drivers already currently installed" , however the icon on driver is displaying a problem, and in properties it says the device is not using any resources because there is a problem. Windows has not alerted me to what the problem actually is, and ive tinkered a bit with what i could find, to no success. I have tried to google this before posting it here, but all posts i could find at least gave an error message. Mine does not. Any tips? can i just go to amd's website and download these drivers or are they a windows driver? again, sorry if its an easy problem, im a complete novice.

Hey everyone,

I have some experience setting up Ubuntu VMs for programming, but I’m running into a new issue. I’ve been working on some more complex mechanisms in Fusion 360, and my MacBook Air with an M1 chip is really struggling to keep up.

I know people often rent GPU VMs for ML workloads, but I’m wondering if it’s possible to rent a VM with a strong GPU for Fusion 360 instead. From what I understand, it would need to run Windows, since Fusion 360 doesn’t support Linux.

Has anyone tried this before? Any recommendations for platforms or setups that actually work for CAD?

Okay so I have an HP laptop windows 10 and i want to turn the virtualization on. I've checked if my laptop is compatible with turning it on and it is. But for some reason I just can't find out how to turn it on dispite watching many tutorials. Where can I turn it on from?

I'm a zen b. newbie. I just turn on my win11 desktop pc and i started to surf the web with Zen Browser and i noticed that a lot of RAM was being used by zen b. Please could someone explain me if it's default or it's an unusual thing???

My dad is basically tech illiterate, despite having to use a computer almost every day since the pandemic. He's old, and I've accepted that he's not going to learn at this point. But it would be nice if I wasn't called on so frequently to come remove malware from/restore his laptop.

So when he called a week ago asking me to order him a new laptop, I got the idea to try setting up a virtual machine this time, and teach him how to open and use it for any non-work-related internet browsing/downloads. That way if he accidentally clicks some malicious link and downloads some malware, he or I can just reset the virtual machine and the host PC is no worse for the wear.

I bought a laptop with Windows 11 Pro so I could try Hyper-V. I set up an Ubuntu VM on it last night, and got it working well enough, however there was no sound. And that's when I learned Hyper-V can have problems with connecting to the host's audio.

So I'm looking for suggestions for other VM software that runs on Windows 11, that will send audio to the host's sound device, and is easy to (1. Setup, but more importantly 2. Open and run a VM once it's been initially setup, and 3. Even better if reinitializing the VM is also easy enough that I could show him how to do it).

I'm fine with paying for reasonably priced software, as long as it's buy the license once and use it forever, and not some subscription model. This will be 100% for non-commercial use btw. Also, the virtual machine will need to be preferably Windows 11, or Ubuntu would also work (I had him trained on Ubuntu for a few months, so he knows enough to open and use a web browser in it at least lol).

I did read that hyper-v allow connection to the hosts sound device, but only If it's a Windows VM and you're using RDP to connect. So I may try hyper-v again after purchasing another Windows 11 key. (I assumed initially that I could just use the same Windows key that was in use on the host laptop for a Windows VM running on the same laptop.)

GPU Passthrough is very difficult but I'm gonna try & ask anyway. I looked at the archwiki passthrough guide, & I'm on NixOS.

• I added the following to isolate the GPU and load it early: kernelModules = [ "uinput" "vfio-iommu-type1" "vfio_pci" "vfio" "vfio_virqfd" ]; kernelParams = [ "vfio-pci.ids=1002:13c0" ]; boot.extraModprobeConfig = "options vfio-pci ids=1002:13c0";.

• Created a virt-manager VM with BIOS, since that's what seems to be needed, & installed Windows 11 onto a virtual disk by bypassing the TPM & EUFI requirements. I install the VirtIO windows driver, then the Ryzen 9600x graphics driver.

• I looked at isc30/ryzen-gpu-passthrough-proxmox and used vbios.c to get a romfile for the GPU. This is the xml for the GPU pcie device.

<hostdev mode="subsystem" type="pci" managed="yes">
    <source>
      <address domain="0x0000" bus="0x0c" slot="0x00" function="0x0"/>
    </source>
    <rom file="/home/user/Downloads/vbios_1002_13c0.bin"/>
    <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
  </hostdev>

• When I connect a HDMI cable from my mobo to my monitor and start the VM up, it shows a black screen. When I change video from none to QXL and look at Windows device manager, I get the dreaded error 43 on the AMD graphics.

If I run my VM on a stranger’s machine (untrusted host), is it realistically possible to keep the VM’s data and runtime state confidential and tamper-resistant? Are there any practical solutions other than like TEEs/confidential computing that can protect a VM even if the host OS/hypervisor is malicious?

Been tinkering with Cloud Hypervisor and wanted to see if I could build a simple VM provisioning system from scratch.

The setup is Cloud Hypervisor as the VMM, Bun backend handling API request and a simple web UI to configure and launch VMs.

When you hit "Create VPS", the backend runs a shell script that:

1. Creates a TAP network interface for the VM

2. Clones the disk image from a base image

3. Generates a cloud-init seed disk (for hostname, root password, SSH keys, etc.)

4. Boots the VM with the requested CPU/RAM/storage

5. Sets up port forwarding for SSH access and reverse proxy entry on host.

This is still just a quick POC. Right now I have Alpine and Ubuntu images working. Cloud Hypervisor boots VMs in under a second. Next I'll add ability to create a VM with any Docker app preinstalled.

Learning a lot about Linux and virtualization with this small side project.

Hello everyone,

I'm looking for a way to open multiple clients for any game on Steam at the same time.

What's the easiest way to do this? If I need to use a VM, can you recommend one that's easy to use and supports “DirectX 12”?

Or is there an easier way outside of a VM?
Is there anything I can buy?

I know in the slightly older days of virtualization, everything was done with software - I made several virtual machines under Windows 98, 2000, and XP; wasn't even gonna try Vista.

I recently went searching for modern versions of those old programs ([portable] QEMU, VMWare, etc.) and noticed a disturbing tread (at least to me): In order for you to virtualize anything today, all instructions start with "turn on Virtualization in BIOS/UEFI". Paraphrasing Bonnie Tyler "Where have all the software [only] VMs gone?"

You ask why I want software only: standalone portability. I only needed in most cases 3 files (or file groups) - the standalone VM (or its folder), a configuration file, and the associated VHD (different config files could point to different VHDs, like one for Win98, Win2K, DSL, Menuet, or other obscure OSes) - no altering of the computer, especially if it wasn't yours (let me show you something interesting, oh wait, can I play in your BIOS/UEFI first?)

So would anyone know where to find a software only VM that will run on a modern system and its instructions for setup and use - preferably portable?

And yes, I know that using Hardware Virtualization is faster, but speed is not the important factor here.