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authorJason J. Herne <jjherne@linux.ibm.com>2024-09-16 14:01:23 +0200
committerVasily Gorbik <gor@linux.ibm.com>2024-09-23 17:57:04 +0200
commit2d8721364ce83956d0a184a64052928589ef15df (patch)
treec4f4a9dac9c075952639f56c54ce0a011b4a4f1e /Documentation
parents390/vdso: Use one large alternative instead of an alternative branch (diff)
downloadlinux-2d8721364ce83956d0a184a64052928589ef15df.tar.xz
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s390/vfio-ap: Driver feature advertisement
Advertise features of the driver for the benefit of automated tooling like Libvirt and mdevctl. Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com> Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com> Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com> Link: https://lore.kernel.org/r/20240916120123.11484-1-jjherne@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arch/s390/vfio-ap.rst30
1 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/arch/s390/vfio-ap.rst b/Documentation/arch/s390/vfio-ap.rst
index ea744cbc8687..eba1991fbdba 100644
--- a/Documentation/arch/s390/vfio-ap.rst
+++ b/Documentation/arch/s390/vfio-ap.rst
@@ -999,6 +999,36 @@ the vfio_ap mediated device to which it is assigned as long as each new APQN
resulting from plugging it in references a queue device bound to the vfio_ap
device driver.
+Driver Features
+===============
+The vfio_ap driver exposes a sysfs file containing supported features.
+This exists so third party tools (like Libvirt and mdevctl) can query the
+availability of specific features.
+
+The features list can be found here: /sys/bus/matrix/devices/matrix/features
+
+Entries are space delimited. Each entry consists of a combination of
+alphanumeric and underscore characters.
+
+Example:
+cat /sys/bus/matrix/devices/matrix/features
+guest_matrix dyn ap_config
+
+the following features are advertised:
+
+---------------+---------------------------------------------------------------+
+| Flag | Description |
++==============+===============================================================+
+| guest_matrix | guest_matrix attribute exists. It reports the matrix of |
+| | adapters and domains that are or will be passed through to a |
+| | guest when the mdev is attached to it. |
++--------------+---------------------------------------------------------------+
+| dyn | Indicates hot plug/unplug of AP adapters, domains and control |
+| | domains for a guest to which the mdev is attached. |
++------------+-----------------------------------------------------------------+
+| ap_config | ap_config interface for one-shot modifications to mdev config |
++--------------+---------------------------------------------------------------+
+
Limitations
===========
Live guest migration is not supported for guests using AP devices without