Merge tag 's390-5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

 - Add ABI to kernel image file which allows e.g. the file utility to
   figure out the kernel version.

 - Wire up clone3 system call.

 - Add support for kasan bitops instrumentation.

 - uapi header cleanup: use __u{16,32,64} instead of uint{16,32,64}_t.

 - Provide proper ARCH_ZONE_DMA_BITS so the s390 DMA zone is correctly
   defined with 2 GB instead of the default value of 1 MB.

 - Farhan Ali leaves the group of vfio-ccw maintainers.

 - Various small vfio-ccw fixes.

 - Add missing locking for airq_areas array in virtio code.

 - Minor qdio improvements.

* tag 's390-5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  MAINTAINERS: vfio-ccw: Remove myself as the maintainer
  s390/mm: use shared variables for sysctl range check
  virtio/s390: fix race on airq_areas[]
  s390/dma: provide proper ARCH_ZONE_DMA_BITS value
  s390/kasan: add bitops instrumentation
  s390/bitops: make test functions return bool
  s390: wire up clone3 system call
  kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test
  s390: use __u{16,32,64} instead of uint{16,32,64}_t in uapi header
  s390/hypfs: fix a typo in the name of a function
  s390/qdio: restrict QAOB usage to IQD unicast queues
  s390/qdio: add sanity checks to the fast-requeue path
  s390: enable detection of kernel version from bzImage
  Documentation: fix vfio-ccw doc
  vfio-ccw: Update documentation for csch/hsch
  vfio-ccw: Don't call cp_free if we are processing a channel program
  vfio-ccw: Set pa_nr to 0 if memory allocation fails for pa_iova_pfn
  vfio-ccw: Fix memory leak and don't call cp_free in cp_init
  vfio-ccw: Fix misleading comment when setting orb.cmd.c64

1 files changed, 28 insertions, 3 deletions

diff --git a/Documentation/s390/vfio-ccw.rst b/Documentation/s390/vfio-ccw.rst
index 1e210c6afa88..fca9c4f5bd9c 100644
--- a/Documentation/s390/vfio-ccw.rst
+++ b/Documentation/s390/vfio-ccw.rst
@@ -180,6 +180,13 @@ The process of how these work together.
    add it to an iommu_group and a vfio_group. Then we could pass through
    the mdev to a guest.
 
+
+VFIO-CCW Regions
+----------------
+
+The vfio-ccw driver exposes MMIO regions to accept requests from and return
+results to userspace.
+
 vfio-ccw I/O region
 -------------------
 
@@ -205,6 +212,25 @@ irb_area stores the I/O result.
 
 ret_code stores a return code for each access of the region.
 
+This region is always available.
+
+vfio-ccw cmd region
+-------------------
+
+The vfio-ccw cmd region is used to accept asynchronous instructions
+from userspace::
+
+  #define VFIO_CCW_ASYNC_CMD_HSCH (1 << 0)
+  #define VFIO_CCW_ASYNC_CMD_CSCH (1 << 1)
+  struct ccw_cmd_region {
+         __u32 command;
+         __u32 ret_code;
+  } __packed;
+
+This region is exposed via region type VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD.
+
+Currently, CLEAR SUBCHANNEL and HALT SUBCHANNEL use this region.
+
 vfio-ccw operation details
 --------------------------
 
@@ -306,9 +332,8 @@ Together with the corresponding work in QEMU, we can bring the passed
 through DASD/ECKD device online in a guest now and use it as a block
 device.
 
-While the current code allows the guest to start channel programs via
-START SUBCHANNEL, support for HALT SUBCHANNEL or CLEAR SUBCHANNEL is
-not yet implemented.
+The current code allows the guest to start channel programs via
+START SUBCHANNEL, and to issue HALT SUBCHANNEL and CLEAR SUBCHANNEL.
 
 vfio-ccw supports classic (command mode) channel I/O only. Transport
 mode (HPF) is not supported.