Merge tag 's390-6.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

 - Clean up and improve vdso code: use SYM_* macros for function and
   data annotations, add CFI annotations to fix GDB unwinding, optimize
   the chacha20 implementation

 - Add vfio-ap driver feature advertisement for use by libvirt and
   mdevctl

* tag 's390-6.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/vfio-ap: Driver feature advertisement
  s390/vdso: Use one large alternative instead of an alternative branch
  s390/vdso: Use SYM_DATA_START_LOCAL()/SYM_DATA_END() for data objects
  tools: Add additional SYM_*() stubs to linkage.h
  s390/vdso: Use macros for annotation of asm functions
  s390/vdso: Add CFI annotations to __arch_chacha20_blocks_nostack()
  s390/vdso: Fix comment within __arch_chacha20_blocks_nostack()
  s390/vdso: Get rid of permutation constants

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