Re: [PATCH v3 0/6] ppc/spapr: Add RTAS error injection support for VFIO EEH

[Narayana Murty N <nnmlinux@linux.ibm.com>]

On 08/06/26 11:01 PM, Anushree Mathur wrote:
> Hi Narayana,
> I tested this patch and saw a qemu crash just after triggering error 
> injection on guest after applying the patch series.
> Here is my full analysis:
>
> 1) Started the guest
> 2) Attached an NVME backplane device to the guest.
> 3) Triggered the error injection on guest console for the attached 
> NVME device.
>
> It came to the following message and the guest crashed:
>
> Injecting an ioa-bus-error...
>
> Following is the qemu logs after crash:
>
>
> 2026-06-08T06:25:16.420015Z qemu-system-ppc64: warning: kernel_irqchip 
> allowed but unavailable: IRQ_XIVE capability must be present for KVM
> Falling back to kernel-irqchip=off
> 2026-06-08T06:25:16.495864Z RTAS: Read 236 bytes from device-tree
> 2026-06-08T06:28:43.769276Z qemu-system-ppc64: 0213:60:00.0 BAR 0: 
> failed to create dma-buf: PCI BAR IOMMU mappings may fail: Invalid 
> argument
> 2026-06-08T13:21:00.218278Z RTAS: Read 236 bytes from device-tree
> 2026-06-08T13:21:05.658991Z qemu-system-ppc64: warning: kernel_irqchip 
> allowed but unavailable: IRQ_XIVE capability must be present for KVM
> Falling back to kernel-irqchip=off
> 2026-06-08T13:21:05.794879Z RTAS: Read 236 bytes from device-tree
> 2026-06-08T13:41:59.736480Z RTAS: Read 236 bytes from device-tree
> 2026-06-08T13:42:13.712991Z qemu-system-ppc64: warning: kernel_irqchip 
> allowed but unavailable: IRQ_XIVE capability must be present for KVM
> Falling back to kernel-irqchip=off
> 2026-06-08T13:42:13.848406Z RTAS: Read 236 bytes from device-tree
> 2026-06-08T14:24:42.012714Z qemu-system-ppc64: 0213:60:00.0 BAR 0: 
> failed to create dma-buf: PCI BAR IOMMU mappings may fail: Invalid 
> argument
> 2026-06-08 14:34:09.570+0000: shutting down, reason=crashed
>
Hi Anushree,

Thank you very much for the detailed crash report and thorough testing!
This is extremely valuable feedback that helped identify a critical bug in
the error injection implementation.

I'll prepare a v4 of the patch series with this fix. Could you please 
test it
again once I send it out? I'd particularly appreciate testing with:
- Multiple PHBs in the system
- Devices attached to different PHBs
- Both IOA bus errors and other error types (if possible)

Thanks again for the excellent bug report!

Best regards,
Narayana Murty N
>
> Thank you,
> Anushree Mathur
>
> On 20/05/26 3:24 PM, Narayana Murty N wrote:
>> This patch series implements comprehensive RTAS-based error injection
>> support for VFIO EEH (Enhanced Error Handling) on PowerPC sPAPR 
>> platforms.
>> The implementation enables guest-initiated PCI error injection for 
>> improved
>> testing and diagnostics of EEH recovery mechanisms.
>>
>> Background
>> ----------
>> EEH is a critical feature on PowerPC platforms that provides error 
>> detection,
>> isolation, and recovery for PCI devices. Testing EEH recovery paths 
>> requires
>> the ability to inject various types of errors into the system. While 
>> physical
>> hardware supports error injection through firmware interfaces, QEMU's 
>> VFIO
>> implementation previously lacked this capability.
>>
>> This series bridges that gap by implementing the IBM RTAS error 
>> injection
>> interface, allowing guests to inject PCI errors through the same 
>> firmware
>> calls used on physical hardware. This enables comprehensive testing 
>> of device
>> drivers' EEH recovery code paths in virtualized environments.
>>
>> Implementation Overview
>> -----------------------
>> The patch series introduces three new RTAS calls:
>>    - ibm,open-errinjct:  Opens an error injection session
>>    - ibm,errinjct:       Injects a specific error type
>>    - ibm,close-errinjct: Closes the error injection session
>>
>> The implementation supports multiple error types including:
>>    - IOA bus errors (32-bit and 64-bit addressing)
>>    - Memory/IO/Config space load/store errors
>>    - DMA read/write errors
>>    - Cache and TLB corruption scenarios
>>    - Special recovery events
>>
>> Tesed on pseries and powernv hosts on kvm guest with errinjct tool.
>>
>> Patch Organization
>> ------------------
>> Patch 1: Adds the VFIO backend for error injection
>> Patch 2: Implements the ibm,errinjct RTAS call handler
>> Patch 3: Adds session management (open/close) RTAS calls
>> Patch 4: Advertises capabilities via device tree properties
>> Patch 5: Refactors EEH specific code/stubs to new files.
>> Patch 6: Updates MAINTAINERS file
>>
>> Changelog:
>> ----------
>> v3:
>>    - Fixed the build failure reported at 
>> https://github.com/p-b-o/qemu-ci/actions/runs/26094993976
>>    - Also fixed a gitlab CI breakage in patch 2 (qemu_log_mask 
>> LOG_UNIMP)
>> v2: Addressed refactor suggestions from Cedric, Pierrick
>> v1: 
>> https://lore.kernel.org/all/20260512071112.9675-1-nnmlinux@linux.ibm.com/ 
>>
>>
>>
>> Narayana Murty N (6):
>>    ppc/spapr: Add VFIO EEH error injection backend
>>    ppc/spapr: Add ibm,errinjct RTAS call handler
>>    ppc/spapr: Add support for 'ibm, open-errinjct' and 'ibm,
>>      close-errinjct'
>>    ppc/spapr: Advertise RTAS error injection call support via FDT
>>      property
>>    ppc/spapr: Split VFIO code and refactor EEH interface
>>    MAINTAINERS: Add entry for sPAPR PCI VFIO EEH support
>>
>>   MAINTAINERS                  |   6 +
>>   hw/ppc/Kconfig               |   2 +-
>>   hw/ppc/meson.build           |   1 +
>>   hw/ppc/spapr.c               | 104 +++++++++++
>>   hw/ppc/spapr_pci.c           | 219 ++++++++++++++++++++++
>>   hw/ppc/spapr_pci_vfio.c      | 314 +------------------------------
>>   hw/ppc/spapr_pci_vfio_eeh.c  | 346 +++++++++++++++++++++++++++++++++++
>>   include/hw/pci-host/spapr.h  |  37 +---
>>   include/hw/ppc/spapr.h       |  57 +++++-
>>   include/hw/ppc/spapr_vfio.h  |  28 +++
>>   stubs/meson.build            |   1 +
>>   stubs/spapr_phb_vfio-stubs.c |  52 ++++++
>>   12 files changed, 816 insertions(+), 351 deletions(-)
>>   create mode 100644 hw/ppc/spapr_pci_vfio_eeh.c
>>   create mode 100644 include/hw/ppc/spapr_vfio.h
>>   create mode 100644 stubs/spapr_phb_vfio-stubs.c