Research · Virtualization
GPU virtualization and passthrough research
How we run GPUs inside virtual machines in production, what the settings are worth, and what broke along the way.
CloudRift, which operates RiftStack, runs three GPU virtualization strategies in production: VFIO passthrough, NVIDIA MIG with AI Enterprise vGPU drivers, and AMD SR-IOV with ROCm. The overview article covers the host-side mechanics, the driver lifecycle, the libvirt domain XML and the trade-offs of each. The host setup guide goes deeper on QEMU/KVM passthrough on Linux: IOMMU groups, driver binding, and the resets and boot failures that cost weekends.
The other two articles come out of running this at scale. One benchmarks six VM configurations to find when vCPU pinning and guest NUMA topology help, when they make no measurable difference, and when they slow multi-GPU jobs. The other is the reset bug we hit on the RTX 5090 and RTX PRO 6000 under passthrough, where a function-level reset times out and only a host reboot brings the card back. We posted a $1,000 bounty, the hardware press picked it up, and a community workaround resolved it. NVIDIA has since acknowledged the bug.
APR 2026 · BENCHMARKS · INFRASTRUCTURE & DEVOPS
GPU VM Performance: Do vCPU Pinning and NUMA Topology Really Matter?
We benchmarked six GPU VM setups to find out when vCPU pinning and guest NUMA topology improve performance, when they make no measurable difference, and when they hurt multi-GPU workloads.
APR 2026 · TUTORIALS · GPU VIRTUALIZATION
GPU Virtualization with VFIO, NVIDIA AI Enterprise, and AMD SR-IOV
A deep dive into the three GPU virtualization strategies we use at CloudRift: VFIO passthrough, NVIDIA MIG with AI Enterprise vGPU drivers, and AMD SR-IOV with ROCm. Covers the host-side mechanics, driver lifecycle, domain XML configuration, and the trade-offs of each approach.
AUG 2025 · TUTORIALS · GPU PASSTHROUGH
Host Setup for Qemu KVM GPU Passthrough with VFIO on Linux
GPU passthrough shouldn’t feel like sorcery. If you’ve ever lost a weekend to half-working configs, random resets, or a guest that only boots when the moon is right, this guide is for you.
AUG 2025 · INFRASTRUCTURE & DEVOPS · GPU
Bug Bounty: NVidia Reset Bug
Hey everyone — we're building a next-gen GPU cloud for AI developers at CloudRift, and we've run into a frustrating issue that's proven nearly impossible to debug. We're turning to the community for help.