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.
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
---
drivers/vfio/pci/vfio_pci_core.c | 2 ++
drivers/vfio/pci/vfio_pci_priv.h | 9 +++++++++
drivers/vfio/pci/vfio_pci_zdev.c | 34 ++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 16 +++++++++++++++
4 files changed, 61 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 3a11e6f450f7..f677705921e6 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1526,6 +1526,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
return vfio_pci_core_feature_token(vdev, flags, arg, argsz);
case VFIO_DEVICE_FEATURE_DMA_BUF:
return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz);
+ case VFIO_DEVICE_FEATURE_ZPCI_ERROR:
+ return vfio_pci_zdev_feature_err(device, flags, arg, argsz);
default:
return -ENOTTY;
}
diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
index 27ac280f00b9..eed69926d8a1 100644
--- a/drivers/vfio/pci/vfio_pci_priv.h
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -89,6 +89,8 @@ 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_feature_err(struct vfio_device *device, u32 flags,
+ void __user *arg, size_t argsz);
#else
static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
struct vfio_info_cap *caps)
@@ -103,6 +105,13 @@ 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)
{}
+
+static inline int vfio_pci_zdev_feature_err(struct vfio_device *device,
+ u32 flags, void __user *arg,
+ size_t argsz)
+{
+ 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 2be37eab9279..261954039aa9 100644
--- a/drivers/vfio/pci/vfio_pci_zdev.c
+++ b/drivers/vfio/pci/vfio_pci_zdev.c
@@ -141,6 +141,40 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
return ret;
}
+int vfio_pci_zdev_feature_err(struct vfio_device *device, u32 flags,
+ void __user *arg, size_t argsz)
+{
+ struct vfio_device_feature_zpci_err err;
+ struct vfio_pci_core_device *vdev =
+ container_of(device, struct vfio_pci_core_device, vdev);
+ struct zpci_dev *zdev = to_zpci(vdev->pdev);
+ int ret;
+ int head = 0;
+
+ if (!zdev)
+ return -ENODEV;
+
+ ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET,
+ sizeof(err));
+ if (ret != 1)
+ return ret;
+
+ mutex_lock(&zdev->pending_errs_lock);
+ if (zdev->pending_errs.count) {
+ head = zdev->pending_errs.head % ZPCI_ERR_PENDING_MAX;
+ err.pec = zdev->pending_errs.err[head].pec;
+ zdev->pending_errs.head++;
+ zdev->pending_errs.count--;
+ err.pending_errors = zdev->pending_errs.count;
+ }
+ mutex_unlock(&zdev->pending_errs_lock);
+
+ if (copy_to_user(arg, &err, sizeof(err)))
+ return -EFAULT;
+
+ return 0;
+}
+
int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev)
{
struct zpci_dev *zdev = to_zpci(vdev->pdev);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ac2329f24141..89b44762ef02 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1506,6 +1506,22 @@ struct vfio_device_feature_dma_buf {
struct vfio_region_dma_range dma_ranges[] __counted_by(nr_ranges);
};
+/**
+ * VFIO_DEVICE_FEATURE_ZPCI_ERROR feature provides PCI error information to
+ * userspace for vfio-pci devices on s390x. On s390x PCI error recovery involves
+ * platform firmware and notification to operating system is done by
+ * architecture specific mechanism. Exposing this information to userspace
+ * allows userspace to take appropriate actions to handle an error on the
+ * device.
+ */
+
+struct vfio_device_feature_zpci_err {
+ __u16 pec;
+ __u8 pending_errors;
+ __u8 pad;
+};
+#define VFIO_DEVICE_FEATURE_ZPCI_ERROR 12
+
/* -------- API for Type1 VFIO IOMMU -------- */
/**
--
2.43.0On Wed Jan 7, 2026 at 7:32 PM CET, Farhan Ali 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.
>
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
> drivers/vfio/pci/vfio_pci_core.c | 2 ++
> drivers/vfio/pci/vfio_pci_priv.h | 9 +++++++++
> drivers/vfio/pci/vfio_pci_zdev.c | 34 ++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 16 +++++++++++++++
> 4 files changed, 61 insertions(+)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 3a11e6f450f7..f677705921e6 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1526,6 +1526,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
> return vfio_pci_core_feature_token(vdev, flags, arg, argsz);
> case VFIO_DEVICE_FEATURE_DMA_BUF:
> return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz);
> + case VFIO_DEVICE_FEATURE_ZPCI_ERROR:
> + return vfio_pci_zdev_feature_err(device, flags, arg, argsz);
Would it make sense to name this more generically, e.g.
VFIO_DEVICE_FEATURE_ERROR_RECOVERY, in case other architectures also want to
support something like this in the future?
-- snip --
>
> 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 2be37eab9279..261954039aa9 100644
> --- a/drivers/vfio/pci/vfio_pci_zdev.c
> +++ b/drivers/vfio/pci/vfio_pci_zdev.c
> @@ -141,6 +141,40 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
> return ret;
> }
>
> +int vfio_pci_zdev_feature_err(struct vfio_device *device, u32 flags,
> + void __user *arg, size_t argsz)
> +{
> + struct vfio_device_feature_zpci_err err;
> + struct vfio_pci_core_device *vdev =
> + container_of(device, struct vfio_pci_core_device, vdev);
> + struct zpci_dev *zdev = to_zpci(vdev->pdev);
> + int ret;
> + int head = 0;
Maybe we should use reverse x-mas notation:
struct vfio_device_feature_zpci_err err;
struct vfio_pci_core_device *vdev;
struct zpci_dev *zdev;
int head = 0;
int ret;
vdev = container_of(device, struct vfio_pci_core_device, vdev);
zdev = to_zpci(vdev->pdev);
-- snip --
On 1/19/2026 8:24 AM, Julian Ruess 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. >> >> Signed-off-by: Farhan Ali<alifm@linux.ibm.com> >> --- >> drivers/vfio/pci/vfio_pci_core.c | 2 ++ >> drivers/vfio/pci/vfio_pci_priv.h | 9 +++++++++ >> drivers/vfio/pci/vfio_pci_zdev.c | 34 ++++++++++++++++++++++++++++++++ >> include/uapi/linux/vfio.h | 16 +++++++++++++++ >> 4 files changed, 61 insertions(+) >> >> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c >> index 3a11e6f450f7..f677705921e6 100644 >> --- a/drivers/vfio/pci/vfio_pci_core.c >> +++ b/drivers/vfio/pci/vfio_pci_core.c >> @@ -1526,6 +1526,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, >> return vfio_pci_core_feature_token(vdev, flags, arg, argsz); >> case VFIO_DEVICE_FEATURE_DMA_BUF: >> return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz); >> + case VFIO_DEVICE_FEATURE_ZPCI_ERROR: >> + return vfio_pci_zdev_feature_err(device, flags, arg, argsz); > Would it make sense to name this more generically, e.g. > VFIO_DEVICE_FEATURE_ERROR_RECOVERY, in case other architectures also want to > support something like this in the future? The error recovery mechanism here and also the uapi structure exposed via this device feature is very specific to zPCI devices. Making this a generic device feature would mean having different uapi structure for zPCI devices vs PCI devices on other architectures. I am not sure that would be desirable and might be cleaner to have separate device feature and separate uapi constructs for zPCI vs other architectures. Thanks Farhan
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