Re: AMD IOMMU issue with hibernate on Asrock X600

[Johannes Stezenbach <js@sig21.net>]

On Tue, Feb 03, 2026 at 11:08:49AM +0530, Vasant Hegde wrote:
> On 1/28/2026 3:01 PM, Johannes Stezenbach wrote:
> > 
> >> [0.000] [  343.790320][ T4340] WARNING: drivers/iommu/amd/init.c:952 at amd_iommu_enable_interrupts+0x4c8/0x550, CPU#0: pm-hibernate/4340
> > 
> > - is it Linux or firmware bug?
> > - if Linux bug: please let me know what to do to help debug it
> > - if firmware bug: what additional tests to run; how to add a quirk
> > 
> > What's the downside of amd_iommu_intr=legacy? Does it only
> > affect kvm guests? What's the relationship with x2APIC?
> 
> If you pass `legacy`, then it only affects kvm. It will not accelerate
> interrupts to guest.
> 
> interrupt acceleration has two modes:
>  AVIC works with xAPIC
>  X2AVIC works with X2APIC.
> 
> Generally BIOS will automatically enables appropriate acceleration mode.

It is strange because dmesg says:

[    2.647593] [    T1] kvm_amd: AVIC enabled
[    2.647598] [    T1] kvm_amd: x2AVIC enabled (max 512 vCPUs)

but no message about x2APIC. If I enable x2APIC in BIOS (default
setting is "auto", other settings are "enable" or "disable") then
there is a message about x2APIC. So it seems BIOS default is
to have x2APIC disabled.

> Can you try below patch?

Sadly it doesn't work, same error on hibernate.


Thanks,
Johannes