Re: [PATCH v20 2/3] vfio-pci/zdev: Add a device feature for error information

[Farhan Ali <alifm@linux.ibm.com>]

On 7/17/2026 2:26 PM, Alex Williamson wrote:
> On Tue, 30 Jun 2026 09:55:52 -0700
> Farhan Ali <alifm@linux.ibm.com> wrote:
>
>> For zPCI devices, we have platform specific error information. The platform
>> firmware provides this error information to the operating system in an
>> architecture specific mechanism. To enable recovery from userspace for
>> these devices, we want to expose this error information to userspace. Add a
>> new device feature to expose this information.
>>
>> Userspace needs to be provide a buffer of fixed size. This size is provided
>> to userspace via the VFIO_DEVICE_INFO_CAP_ZPCI_BASE capability.
>>
>> Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
>> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>>   arch/s390/include/asm/pci.h      |  2 ++
>>   arch/s390/pci/pci_event.c        | 19 ++++++++++++++
>>   drivers/vfio/pci/vfio_pci_core.c |  2 ++
>>   drivers/vfio/pci/vfio_pci_priv.h |  9 +++++++
>>   drivers/vfio/pci/vfio_pci_zdev.c | 45 ++++++++++++++++++++++++++++++--
>>   include/uapi/linux/vfio.h        | 23 ++++++++++++++++
>>   include/uapi/linux/vfio_zdev.h   |  2 ++
>>   7 files changed, 100 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
>> index 016386f7ef4a..88a125b92bdd 100644
>> --- a/arch/s390/include/asm/pci.h
>> +++ b/arch/s390/include/asm/pci.h
>> @@ -364,6 +364,8 @@ int zpci_clear_error_state(struct zpci_dev *zdev);
>>   int zpci_reset_load_store_blocked(struct zpci_dev *zdev);
>>   void zpci_start_mediated_recovery(struct zpci_dev *zdev);
>>   void zpci_stop_mediated_recovery(struct zpci_dev *zdev);
>> +int zpci_get_pending_error(struct zpci_dev *zdev,
>> +			   struct zpci_ccdf_err *ccdf);
>>   
>>   #ifdef CONFIG_NUMA
>>   
>> diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
>> index 8934b640a095..3ad16038e005 100644
>> --- a/arch/s390/pci/pci_event.c
>> +++ b/arch/s390/pci/pci_event.c
>> @@ -77,6 +77,25 @@ static int zpci_store_pci_error(struct pci_dev *pdev,
>>   	return 0;
>>   }
>>   
>> +int zpci_get_pending_error(struct zpci_dev *zdev,
>> +			   struct zpci_ccdf_err *ccdf)
>> +{
>> +	int head = 0;
> Nit, unnecessary initialization.
>
> Otherwise LGTM and I can drop the initialization on commit if there's
> no other reason for respin.  I think we just need a branch from Bjorn
> to base this on once he's happy with the PCI series.  Thanks,
>
> Alex

Hi Alex,

Bjorn has accepted the PCI patches and merged it to his pci/slot 
tree[1]. Would you be able to merge the vfio patches? I was able to 
apply these patches on 7.2-rc7 and didn't have any conflicts. But let me 
know if you need me to respin.

Thanks again for all your help reviewing this series.

Thanks

Farhan



>
>> +
>> +	guard(mutex)(&zdev->pending_errs_lock);
>> +
>> +	if (!zdev->pending_errs.count)
>> +		return -ENOMSG;
>> +
>> +	head = zdev->pending_errs.head % ZPCI_ERR_PENDING_MAX;
>> +	memcpy(ccdf, &zdev->pending_errs.err[head],
>> +	       sizeof(struct zpci_ccdf_err));
>> +	zdev->pending_errs.head++;
>> +	zdev->pending_errs.count--;
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(zpci_get_pending_error);
>> +
>>   void zpci_start_mediated_recovery(struct zpci_dev *zdev)
>>   {
>>   	guard(mutex)(&zdev->pending_errs_lock);