On 8/13/2025 1:30 PM, Alex Williamson wrote:
On Wed, 13 Aug 2025 10:08:19 -0700
Farhan Ali <alifm@xxxxxxxxxxxxx> wrote:
For zPCI devices we should drive a platform specific function reset
as part of VFIO_DEVICE_RESET. This reset is needed recover a zPCI device
in error state.
Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
---
arch/s390/pci/pci.c | 1 +
drivers/vfio/pci/vfio_pci_core.c | 4 ++++
drivers/vfio/pci/vfio_pci_priv.h | 5 ++++
drivers/vfio/pci/vfio_pci_zdev.c | 39 ++++++++++++++++++++++++++++++++
4 files changed, 49 insertions(+)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index f795e05b5001..860a64993b58 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -788,6 +788,7 @@ int zpci_hot_reset_device(struct zpci_dev *zdev)
return rc;
}
+EXPORT_SYMBOL_GPL(zpci_hot_reset_device);
/**
* zpci_create_device() - Create a new zpci_dev and add it to the zbus
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 7dcf5439dedc..7220a22135a9 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1227,6 +1227,10 @@ static int vfio_pci_ioctl_reset(struct vfio_pci_core_device *vdev,
*/
vfio_pci_set_power_state(vdev, PCI_D0);
+ ret = vfio_pci_zdev_reset(vdev);
+ if (ret && ret != -ENODEV)
+ return ret;
+
ret = pci_try_reset_function(vdev->pdev);
up_write(&vdev->memory_lock);
You're going to be very unhappy if this lock isn't released.
Ah yes, thanks for catching that. Will fix this.
diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
index a9972eacb293..5288577b3170 100644
--- a/drivers/vfio/pci/vfio_pci_priv.h
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -86,6 +86,7 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
struct vfio_info_cap *caps);
int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev);
void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev);
+int vfio_pci_zdev_reset(struct vfio_pci_core_device *vdev);
#else
static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
struct vfio_info_cap *caps)
@@ -100,6 +101,10 @@ static inline int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev)
static inline void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev)
{}
+int vfio_pci_zdev_reset(struct vfio_pci_core_device *vdev)
+{
+ return -ENODEV;
+}
#endif
static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c
index 818235b28caa..dd1919ccb3be 100644
--- a/drivers/vfio/pci/vfio_pci_zdev.c
+++ b/drivers/vfio/pci/vfio_pci_zdev.c
@@ -212,6 +212,45 @@ static int vfio_pci_zdev_setup_err_region(struct vfio_pci_core_device *vdev)
return ret;
}
+int vfio_pci_zdev_reset(struct vfio_pci_core_device *vdev)
+{
+ struct zpci_dev *zdev = to_zpci(vdev->pdev);
+ int rc = -EIO;
+
+ if (!zdev)
+ return -ENODEV;
+
+ /*
+ * If we can't get the zdev->state_lock the device state is
+ * currently undergoing a transition and we bail out - just
+ * the same as if the device's state is not configured at all.
+ */
+ if (!mutex_trylock(&zdev->state_lock))
+ return rc;
+
+ /* We can reset only if the function is configured */
+ if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
+ goto out;
+
+ rc = zpci_hot_reset_device(zdev);
+ if (rc != 0)
+ goto out;
+
+ if (!vdev->pci_saved_state) {
+ pci_err(vdev->pdev, "No saved available for the device");
+ rc = -EIO;
+ goto out;
+ }
+
+ pci_dev_lock(vdev->pdev);
+ pci_load_saved_state(vdev->pdev, vdev->pci_saved_state);
+ pci_restore_state(vdev->pdev);
+ pci_dev_unlock(vdev->pdev);
+out:
+ mutex_unlock(&zdev->state_lock);
+ return rc;
+}
This looks like it should be a device or arch specific reset
implemented in drivers/pci, not vfio. Thanks,
Alex
Are you suggesting to move this to an arch specific function? One thing
we need to do after the zpci_hot_reset_device, is to correctly restore
the config space of the device. And for vfio-pci bound devices we want
to restore the state of the device to when it was initially opened.
Thanks
Farhan
+
int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev)
{
struct zpci_dev *zdev = to_zpci(vdev->pdev);
