Database/Kernel, userspace & hypervisor
Linux KVM - irqfd routing type clobbered on deassign: MULTI-TENANT ISOLATION: Deassigning a KVM_IRQFD clobbers
Impact
MULTI-TENANT ISOLATION: Deassigning a KVM_IRQFD clobbers the irqfd's copy of the interrupt routing entry, leaving stale or wrong routing behind. Interrupt routing decides which guest receives which interrupt, so corrupting it on teardown is a cross-VM correctness failure on the interrupt path - and on a GPU host, irqfd is exactly how passed-through accelerator interrupts reach their guest.
Who can reach it
Through the KVM ioctl interface, from the VMM process managing guests - reachable when devices are hot-unplugged or VMs torn down.
What to do
Fixed in the Linux kernel. Distro kernel update plus host reboot; no firmware step. Relevant to any fleet doing GPU passthrough with dynamic device attach/detach.
References
This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.