# Single GPU passthrough with QEMU and VFIO
<!-- AKA Passthrough VGA on first slot -->
----
## What this does
In one command it kills X, frees the GPU from drivers and console, detaches the GPU from the host, starts the VM with the GPU, waits until the VM is off, reattaches the GPU to the host and starts lightdm.

## ToC (Table of Contents)

## What you need
* An IOMMU enabled motherboard. Check your motherboard manual.
* CPU support for AMD-v/VT-x and AMD-Vi/VT-d (AMD/Intel). And virtualization support enabled on BIOS.
* One GPU that supports UEFI and its BIOS. All GPUs from 2012 and later should support this.
* QEMU, OVMF UEFI and VIRTIO drivers for Windows.
* [Optional] HDD only for Windows

## My system
```
                                                [Hardware]
                                                 CPU: AMD Ryzen 5 2600
                                         Motherboard: Gigabyte AB350M-Gaming 3 rev1.1
                                    Motherboard BIOS: F23d
                                                 RAM: 16GB
                                                 GPU: Gigabyte Nvidia GeForce GTX 770
                                           GPU model: GV-N770OC-2GD
                                            GPU BIOS: 80.04.C3.00.0F
                                        GPU codename: GK104

                                                [Software]
                                        Linux Distro: ArchLinux
                                        Linux Kernel: 4.17.11 vanilla
                                       Nvidia divers: 396.45-2
                                        QEMU version: 2.12.0-2
                                        OVMF version: r24021

                                                 [Guests]
                                             Windows: Windows 10 Pro 1709 x64
                                               MacOS: MacOS 10.13.3

```  

## Configure
1. Clone this repository
```bash
git clone https://gitlab.com/YuriAlek/vfio.git
```

2. Enable vfio at boot. Edit `/etc/mkinitcpio.conf`
```
MODULES=(... vfio_pci vfio vfio_iommu_type1 vfio_virqfd ...)
HOOKS=(... modconf ...)
```

3. [Regenerate the initramfs][initramfs_archwiki]
```bash
sudo mkinitcpio -p linux
```

4. Reboot the system to load the vfio drivers

5. (Optional)[Download virtio drivers][virtio_drivers]
```
wget -o virtio-win.iso "https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso"
```

6. Get the GPU BIOS [Source][GPU_BIOS_video] [Why?][]
[You can download the bios.][techpowerup vgabios] If you do so, download a HEX editor and skip to step 4.
1. Boot the host into Windows.
2. [Download and install GPU-Z][GPU-Z].
3. [Download and install a HEX editor][bless].
3. Open GPU-Z and backup the GPU BIOS. Right next to the `Bios Version`; in my case `80.04.C3.00.0F`, there is an icon for backup. A file named `GK104.rom` will be created. [There is also a way of doing it in Linux][] but it did not work for me.
4. Open the ROM (`GK104.rom`) in the HEX editor.
5. After a bunch of `00` there is a `55` or `U` in HEX, delete everything before the `55`, and save. I strongly recommend not to overwrite the original ROM.

And you must supply QEMU with the Full GPU's ROM extracted extracted using a tool called "nvagetbios" , which you can find in a package called "envytools"



\\ Mod this section, refer to guide
7. Get the iommu groups needed for the VM (GPU, GPU audio and USB controller)
```bash
chmod +x scripts/iommu.sh
bash scripts/iommu.sh
----
# GPU
IOMMU group 13
	06:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK104 [GeForce GTX 770] [10de:1184] (rev a1)
	06:00.1 Audio device [0403]: NVIDIA Corporation GK104 HDMI Audio Controller [10de:0e0a] (rev a1)
# USB 3.0 Controller
IOMMU group 16
	07:00.3 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] USB 3.0 Host controller [1022:145f]
# SATA Controller
IOMMU group 18
	08:00.2 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
```

8. (Optional) Create the image for the VM
```
qemu-img create -f raw windows.raw 60G
```

9. Edit the script `windows-install.sh` and `windows.sh` to convenience
Things you may have to edit:
  1. PCI devices
  2. User
  3. Location of HDD, vBIOS and OVMF image
  4. The Desktop Environment, Display Manager, Windows Manager, etc.
  5. QEMU options like RAM and CPU config
  6. Kernel modules
Check the guides [IOMMU][], [other guide, may be important][]

10. Start the VM
```
sudo scripts/windows-install.sh
```

11. Install Windows
When you are asked for a hard drive there will be none.
  1. Load driver
  2. Browse
  3. CD Drive (E:) virtio-win-0.1.1
  4. vioscsi
  5. w10
  6. amd64
  7. ok
  8. Load driver `Red Hat VirtIO SCSI pass-through controller (E:\vioscsi\w10\amd64\vioscsi.inf)`
  9. Next
  10. Select the `Unallocated Space`
  11. Proceed as normal.
  12. Let Windows find the drivers for the GPU (if Windows has network) or [download the updated ones from NVIDIA][GPU_drivers].

12. Once installed Windows, run the VM with
```
sudo scripts/windows.sh
```

## For the sake of convenience
sudo ln -s /home/yu/scripts/qemu@.service /usr/lib/systemd/system/
alias fuckmicrosoft="sudo systemctl start qemu@windows.service"

## About peripherals
For audio I use an USB sound card.
For internet I use network.sh
For USB I simply passthrough an USB 3.0 controller.

## Known problems
### Race condition
There is something somewhere that makes it crash. That's why there is so many `sleep 1`

### Root
QEMU should never be run as root. If you must launch it in a script as root, you should use the `-runas` option to make QEMU drop root privileges.