Re: [PATCH v5 14/15] s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The newly added 'migratable' feature is not documented in the Driver Features table, and the Limitations section explicitly states migration is not supported.
--

--- Patch [14]: [PATCH v5 14/15] s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute ---
commit c8392bd6bcb1403c66327e9551bbba5ecd4a167d
Author: Anthony Krowiak <akrowiak@linux.ibm.com>

s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute

This commit adds the 'migratable' feature to the sysfs features attribute
for vfio_ap. This exposes the feature to userspace, indicating that
migration of vfio devices is supported.

> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 8e69ed286bb9c..4e973736522bc 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -26,9 +26,11 @@ MODULE_LICENSE("GPL v2");
>  struct ap_matrix_dev *matrix_dev;
>  debug_info_t *vfio_ap_dbf_info;
>  
> +#define FEATURES "guest_matrix hotplug ap_config migratable"

[Severity: Low]
Since this adds the 'migratable' feature, shouldn't
Documentation/arch/s390/vfio-ap.rst be updated to reflect this capability?

Looking at that file, the "Driver Features" table appears to be missing an
entry for this newly added 'migratable' flag.

Additionally, the "Limitations" section in the same document explicitly
states: "Live guest migration is not supported for guests using AP devices
without intervention by a system administrator."

Does this patch series render that limitation obsolete? If so, should that
section be updated or removed to avoid confusing users?

> +
>  static ssize_t features_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	return sysfs_emit(buf, "guest_matrix hotplug ap_config\n");
> +	return sysfs_emit(buf, "%s\n", FEATURES);
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260724161351.1802644-1-akrowiak@linux.ibm.com?part=14