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

["Cédric Le Goater" <clg@redhat.com>]

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.



>   #endif
>   
>   #endif