Linux 6.9 VFIO Updates Bring A New Driver For NVIDIA's Grace-Hopper Superchip

The Virtual Function I/O (VFIO) updates for the Linux 6.9 merge window bring a mostly mundane assortment of driver patches and other routine changes. But there is a new driver for NVIDIA's Grace-Hopper superchip.

NVIDIA has contributed a VFIO PCI variant module for the Grace Hopper Superchip to deal with peculiarities of that massive chip.

The VFIO pull request for Linux 6.9 explains of the new NVIDIA code:

"Addition of a new vfio-pci variant driver for the GPU of NVIDIA's Grace-Hopper superchip. During initialization of the chip-to-chip interconnect in this hardware module, the PCI BARs of the device become unused in favor of a faster, coherent mechanism for exposingdevice memory. This driver primarily changes the VFIO representation of the device to masquerade this coherent aperture to replace the physical PCI BARs for userspace drivers. This also incorporates use of a new vma flag allowing KVM to use write combining attributes for uncached device memory."

This patch message further describes the new VFIO driver code for NVIDIA's Grace Hopper if interested. Great seeing the continued NVIDIA upstreaming efforts to the Linux kernel where the business need presents itself.