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Diffstat (limited to 'Documentation/s390')
| -rw-r--r-- | Documentation/s390/vfio-ccw.rst | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/Documentation/s390/vfio-ccw.rst b/Documentation/s390/vfio-ccw.rst index 3a946fd45562..32310df525ba 100644 --- a/Documentation/s390/vfio-ccw.rst +++ b/Documentation/s390/vfio-ccw.rst @@ -282,6 +282,21 @@ for each access of the region. The following values may occur: ``-EBUSY`` The subchannel was status pending or busy while processing a halt request. +vfio-ccw schib region +--------------------- + +The vfio-ccw schib region is used to return Subchannel-Information +Block (SCHIB) data to userspace:: + + struct ccw_schib_region { + #define SCHIB_AREA_SIZE 52 + __u8 schib_area[SCHIB_AREA_SIZE]; + } __packed; + +This region is exposed via region type VFIO_REGION_SUBTYPE_CCW_SCHIB. + +Reading this region triggers a STORE SUBCHANNEL to be issued to the +associated hardware. vfio-ccw operation details -------------------------- @@ -385,7 +400,8 @@ through DASD/ECKD device online in a guest now and use it as a block device. The current code allows the guest to start channel programs via -START SUBCHANNEL, and to issue HALT SUBCHANNEL and CLEAR SUBCHANNEL. +START SUBCHANNEL, and to issue HALT SUBCHANNEL, CLEAR SUBCHANNEL, +and STORE SUBCHANNEL. Currently all channel programs are prefetched, regardless of the p-bit setting in the ORB. As a result, self modifying channel |