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| author | Farhan Ali <alifm@linux.ibm.com> | 2020-05-05 15:27:41 +0300 |
|---|---|---|
| committer | Cornelia Huck <cohuck@redhat.com> | 2020-06-02 14:14:08 +0300 |
| commit | 24c986748ba670c903a9d6a11ee96de2b3f5f1b8 (patch) | |
| tree | 4117927cb0d8a23c596dc72b5e0f22f1213efd46 /Documentation/s390 | |
| parent | 600279b52659c8211c6625fb2c9cd8bf8de15061 (diff) | |
| download | linux-24c986748ba670c903a9d6a11ee96de2b3f5f1b8.tar.xz | |
vfio-ccw: Introduce a new schib region
The schib region can be used by userspace to get the subchannel-
information block (SCHIB) for the passthrough subchannel.
This can be useful to get information such as channel path
information via the SCHIB.PMCW fields.
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20200505122745.53208-5-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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 |