VFIO is about running for example Windows 10 in a virtual machine (VM), using a discrete graphics card that you pass through to the VM. The Linux driver framework that is used to bind the graphics card during the host boot is called VFIO. The virtual machine itself (e.g. Windows 10) then uses its own native graphics driver to drive the GPU, significantly boosting VM graphics performance. This enables you to run Linux on the host and create Windows virtual machines for gaming and other high performance tasks.
AMD graphics cards have been plagued with the notorious FLR reset bug over several years now. Independent developers wrote a kernel patch as a workaround that would work most of the time. But the patch required kernel or module compilation, which is not everyone’s cup of tea.
Yesterday Wendell at Level1Techs posted a (p)review of the latest AMD Radeon 6800 and 6800XT graphics cards. He attests that the AMD Radeon 6800/6800XT are perfectly suitable for VFIO passthrough. No more FLR reset bug. Wendell goes further to point out that the Linux graphics drivers available in Ubuntu 20.04 already support these cards. This is great news for the Linux user community in general, and VFIO passthrough enthusiasts especially! Finally an alternative to NVIDIA.
There are more good news: Those of you who already own an AMD Navi, Vega or Polaris graphics card plagued with the FLR reset bug can now enjoy a simpler, better workaround. Instead of compiling the patch into the kernel, all you need to do now is to “build the module and modprobe it, or use dmks to manage it directly”.
AMD has already shown its Linux support through its open source graphics drivers. The new graphics cards based on the RDNA2 architecture have finally corrected the product flaw of previous releases. Welcome to the VFIO club.
You will probably have to wait some time to get hold of one of these cards, as they seem to have sold out on launch day.
I’ve already written a detailed tutorial on VGA passthrough based on QEMU version 2.11. Time has passed and today distributions like Ubuntu 20.04, Linux Mint 20, or Manjaro come with QEMU 4.0, 4.2 or 5.0.
It wasn’t easy this time. Don’t get me wrong – the VFIO passthrough part, though challenging in some ways, went quite well. All in all I’m pleased now with the results. Here the Passmark 9.0 benchmark as uploaded onto their database (for more details, click the frame below):
I’ve been contemplating a PC upgrade for more than a year (see my post here). At first I considered staying with Intel and getting an i9-9900K CPU with integrated GPU on a Z390 motherboard.
Along came the AMD Ryzen 9 3900X that topped the benchmarks, including the Adobe Lightroom and Photoshop benchmarks (to be precise, it ranked #4 in the Adobe Lightroom benchmark, and a narrow #1 in the Adobe Photoshop benchmark). These good news about the AMD Ryzen 3900X were soon followed by reports about BIOS issues and VFIO incompatibility. At the very least, it looked like VGA passthrough was more challenging.
A year ago I wrote about the 2D graphics performance impact of the Windows 10 (1803) update inside a virtual machine. As it turned out, the performance impact was related to the Spectre vulnerability patch that Microsoft had introduced. However, the same patch had practically no performance impact on a Windows 10 bare-metal installation.
For some time I wanted to run a kvm virtual machine with GPU passthrough on a low-end Asus H110M-K D3 motherboard with an i3-6100 CPU and an Nvidia GTX 1060 GPU, but never found the time. Now I finally had a chance to give it a try. While the preparations were easy, I ran into a problem when starting the Windows 10 VM:
When running a VM with GPU passthrough, that GPU should be bound to the VFIO driver. To make this happen, we need to prevent the regular graphics driver from binding to the passthrough GPU and instead bind the vfio-pci driver.
Back in 2012 I built a PC around the Intel i7 3930K 6-core/12HT processor which I have been using ever since. While it’s still a strong PC, especially with the upgrades (GPU, SSD) I made, I’m starting to feel that editing photos isn’t as snappy as it used to be. I am also curious in how well the new generation of CPUs lend themselves to VGA passthrough. In short, I’m considering building a new PC. Continue reading “New PC Build”
You may wonder what’s wrong with this fellow (meaning me, the author). Has he completely lost his mind when he proposes a Linux virtual gaming machine? Before you discredit the idea, let me explain. Continue reading “Linux Virtual Gaming Machine”