Re: [BUG] Continuously increasing spurious interrupts inside pSeries guest on PowerNV host

----- Original Message -----
> From: "Timothy Pearson" <[email protected]>
> To: "linuxppc-dev" <[email protected]>
> Cc: "Ritesh Harjani" <[email protected]>
> Sent: Friday, August 14, 2026 9:56:30 AM
> Subject: [BUG] Continuously increasing spurious interrupts inside pSeries guest on PowerNV host

> 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.

Actually, I don't know where the spurious interrupts are coming from.  This is in XIVE mode.  Switching to XICS mode via -M pseries,ic-mode=xics greatly reduces the rate of spurious interrupts, but does not eliminate them.

I don't recall this being an issue on the 5.x series kernels, but do not have the ability to test either those or the 7.x series at the moment.