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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 10:06:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 10:06:12 -0700
commit1758feddb0f9751debdc865fefde94b45907c948 (patch)
tree3b677285709b730e572724dcdd925e43333f2d45 /Documentation/ABI
parent278ecbf027c3c559deb225f0cf53a23b7672dacf (diff)
parent499723d12063aab97dfe6b41c822e9c1c74eff3e (diff)
downloadlinux-1758feddb0f9751debdc865fefde94b45907c948.tar.bz2
Merge tag 's390-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik: - Improve stop_machine wait logic: replace cpu_relax_yield call in generic stop_machine function with a weak stop_machine_yield function. This is overridden on s390, which yields the current cpu to the neighbouring cpu after a couple of retries, instead of blindly giving up the cpu to the hipervisor. This significantly improves stop_machine performance on s390 in overcommitted scenarios. This includes common code changes which have been Acked by Peter Zijlstra and Thomas Gleixner. - Improve jump label transformation speed: transform jump labels without using stop_machine. - Refactoring of the vfio-ccw cp handling, simplifying the code and avoiding unneeded allocating/copying. - Various vfio-ccw fixes (ccw translation, state machine). - Add support for vfio-ap queue interrupt control in the guest. This includes s390 kvm changes which have been Acked by Christian Borntraeger. - Add protected virtualization support for virtio-ccw. - Enforce both CONFIG_SMP and CONFIG_HOTPLUG_CPU, which allows to remove some code which most likely isn't working at all, besides that s390 didn't even compile for !CONFIG_SMP. - Support for special flagged EP11 CPRBs for zcrypt. - Handle PCI devices with no support for new MIO instructions. - Avoid KASAN false positives in reworked stack unwinder. - Couple of fixes for the QDIO layer. - Convert s390 specific documentation to ReST format. - Let s390 crypto modules return -ENODEV instead of -EOPNOTSUPP if hardware is missing. This way our modules behave like most other modules and which is also what systemd's systemd-modules-load.service expects. - Replace defconfig with performance_defconfig, so there is one config file less to maintain. - Remove the SCLP call home device driver, which was never useful. - Cleanups all over the place. * tag 's390-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (83 commits) docs: s390: s390dbf: typos and formatting, update crash command docs: s390: unify and update s390dbf kdocs at debug.c docs: s390: restore important non-kdoc parts of s390dbf.rst vfio-ccw: Fix the conversion of Format-0 CCWs to Format-1 s390/pci: correctly handle MIO opt-out s390/pci: deal with devices that have no support for MIO instructions s390: ap: kvm: Enable PQAP/AQIC facility for the guest s390: ap: implement PAPQ AQIC interception in kernel vfio: ap: register IOMMU VFIO notifier s390: ap: kvm: add PQAP interception for AQIC s390/unwind: cleanup unused READ_ONCE_TASK_STACK s390/kasan: avoid false positives during stack unwind s390/qdio: don't touch the dsci in tiqdio_add_input_queues() s390/qdio: (re-)initialize tiqdio list entries s390/dasd: Fix a precision vs width bug in dasd_feature_list() s390/cio: introduce driver_override on the css bus vfio-ccw: make convert_ccw0_to_ccw1 static vfio-ccw: Remove copy_ccw_from_iova() vfio-ccw: Factor out the ccw0-to-ccw1 transition vfio-ccw: Copy CCW data outside length calculation ...
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-css23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-css b/Documentation/ABI/testing/sysfs-bus-css
index 2979c40c10e9..966f8504bd7b 100644
--- a/Documentation/ABI/testing/sysfs-bus-css
+++ b/Documentation/ABI/testing/sysfs-bus-css
@@ -33,3 +33,26 @@ Description: Contains the PIM/PAM/POM values, as reported by the
in sync with the values current in the channel subsystem).
Note: This is an I/O-subchannel specific attribute.
Users: s390-tools, HAL
+
+What: /sys/bus/css/devices/.../driver_override
+Date: June 2019
+Contact: Cornelia Huck <cohuck@redhat.com>
+ linux-s390@vger.kernel.org
+Description: This file allows the driver for a device to be specified. When
+ specified, only a driver with a name matching the value written
+ to driver_override will have an opportunity to bind to the
+ device. The override is specified by writing a string to the
+ driver_override file (echo vfio-ccw > driver_override) and
+ may be cleared with an empty string (echo > driver_override).
+ This returns the device to standard matching rules binding.
+ Writing to driver_override does not automatically unbind the
+ device from its current driver or make any attempt to
+ automatically load the specified driver. If no driver with a
+ matching name is currently loaded in the kernel, the device
+ will not bind to any driver. This also allows devices to
+ opt-out of driver binding using a driver_override name such as
+ "none". Only a single driver may be specified in the override,
+ there is no support for parsing delimiters.
+ Note that unlike the mechanism of the same name for pci, this
+ file does not allow to override basic matching rules. I.e.,
+ the driver must still match the subchannel type of the device.