Re: [PATCH v2 4/4] s390x/pci: Reset a device in error state

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

On 9/1/2025 4:17 AM, Cédric Le Goater wrote:
> On 8/25/25 23:24, Farhan Ali wrote:
>> For passthrough devices in error state, for a guest driven reset of the
>> device we can attempt a reset to recover the device. A reset of the 
>> device
>> will trigger a CLP disable/enable cycle on the host to bring the device
>> into a recovered state.
>>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> ---
>>   hw/s390x/s390-pci-bus.c          | 7 +++++++
>>   hw/s390x/s390-pci-vfio.c         | 6 ++++++
>>   include/hw/s390x/s390-pci-vfio.h | 2 ++
>>   3 files changed, 15 insertions(+)
>>
>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
>> index af42eb9938..c9c2d775f0 100644
>> --- a/hw/s390x/s390-pci-bus.c
>> +++ b/hw/s390x/s390-pci-bus.c
>> @@ -1493,6 +1493,8 @@ static void s390_pci_device_reset(DeviceState 
>> *dev)
>>           return;
>>       case ZPCI_FS_STANDBY:
>>           break;
>> +    case ZPCI_FS_ERROR:
>> +        break;
>>       default:
>>           pbdev->fh &= ~FH_MASK_ENABLE;
>>           pbdev->state = ZPCI_FS_DISABLED;
>> @@ -1505,6 +1507,11 @@ static void s390_pci_device_reset(DeviceState 
>> *dev)
>>       } else if (pbdev->summary_ind) {
>>           pci_dereg_irqs(pbdev);
>>       }
>> +
>> +    if (pbdev->state == ZPCI_FS_ERROR) {
>> +        s390_pci_reset(pbdev);
>> +    }
>> +
>>       if (pbdev->iommu->enabled) {
>>           pci_dereg_ioat(pbdev->iommu);
>>       }
>> diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
>> index 87ecd06a81..a11ec770a7 100644
>> --- a/hw/s390x/s390-pci-vfio.c
>> +++ b/hw/s390x/s390-pci-vfio.c
>> @@ -158,6 +158,12 @@ static void s390_pci_err_handler(VFIOPCIDevice 
>> *vfio_pci)
>>       return;
>>   }
>>   +void s390_pci_reset(S390PCIBusDevice *pbdev)
>> +{
>> +    VFIOPCIDevice *vfio_pci = container_of(pbdev->pdev, 
>> VFIOPCIDevice, pdev);
>> +    ioctl(vfio_pci->vbasedev.fd, VFIO_DEVICE_RESET);
>> +}
>> +
>>   static void s390_pci_read_base(S390PCIBusDevice *pbdev,
>>                                  struct vfio_device_info *info)
>>   {
>> diff --git a/include/hw/s390x/s390-pci-vfio.h 
>> b/include/hw/s390x/s390-pci-vfio.h
>> index 66b274293c..c28dafeed8 100644
>> --- a/include/hw/s390x/s390-pci-vfio.h
>> +++ b/include/hw/s390x/s390-pci-vfio.h
>> @@ -23,6 +23,7 @@ void s390_pci_end_dma_count(S390pciState *s, 
>> S390PCIDMACount *cnt);
>>   bool s390_pci_get_host_fh(S390PCIBusDevice *pbdev, uint32_t *fh);
>>   void s390_pci_get_clp_info(S390PCIBusDevice *pbdev);
>>   void s390_pci_setup_err_handler(S390PCIBusDevice *pbdev);
>> +void s390_pci_reset(S390PCIBusDevice *pbdev);
>>   #else
>>   static inline bool s390_pci_update_dma_avail(int fd, unsigned int 
>> *avail)
>>   {
>> @@ -41,6 +42,7 @@ static inline bool 
>> s390_pci_get_host_fh(S390PCIBusDevice *pbdev, uint32_t *fh)
>>   }
>>   static inline void s390_pci_get_clp_info(S390PCIBusDevice *pbdev) { }
>>   static inline void s390_pci_setup_err_handler(S390PCIBusDevice 
>> *pbdev) { }
>> +void s390_pci_reset(S390PCIBusDevice *pbdev) { }
>
> static inline void ... ^
>
>
> Thanks,
>
> C.

Ack, will change.

Thanks

Farhan


>
>
>
>>   #endif
>>     #endif
>
>