With kernel 6.12 (Debian stable) we see a continuously increasing spurious
interrupt count inside a pSeries guest running on a PowerNV host:
cat /proc/interrupts
CPU0
16: 0 XIVE-IPI 0 Edge IPI-0
17: 0 XIVE-IRQ 4096 Edge RAS_EPOW
21: 2 XIVE-IRQ 4353 Edge hvc_console
23: 0 XIVE-IRQ 4097 Edge RAS_HOTPLUG
24: 0 pSeries-PCI-MSI 0 Edge virtio0-config
25: 50995 pSeries-PCI-MSI 1 Edge virtio0-input.0
26: 45569 pSeries-PCI-MSI 2 Edge virtio0-output.0
27: 0 pSeries-PCI-MSI 16384 Edge virtio1-config
28: 6 pSeries-PCI-MSI 16385 Edge virtio1-input
LOC: 5781 Local timer interrupts for timer event device
BCT: 0 Broadcast timer interrupts for timer event device
LOC: 2 Local timer interrupts for others
SPU: 449927 Spurious interrupts
PMI: 0 Performance monitoring interrupts
MCE: 0 Machine check exceptions
NMI: 0 System Reset interrupts
WDG: 0 Watchdog soft-NMI interrupts
DBL: 0 Doorbell interrupts
The spurious interrupts are apparently from the virtio0-[input|output] devices.