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

[Cédric Le Goater]

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 <al...@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