ich777/linux_media
1
0
Fork 0
mirror of https://github.com/tbsdtv/linux_media.git synced 2025-07-23 04:33:26 +02:00
Code Issues Packages Projects Releases Wiki Activity

vfio-ccw: Introduce a new CRW region

Browse Source 
This region provides a mechanism to pass a Channel Report Word
that affect vfio-ccw devices, and needs to be passed to the guest
for its awareness and/or processing.

The base driver (see crw_collect_info()) provides space for two
CRWs, as a subchannel event may have two CRWs chained together
(one for the ssid, one for the subchannel).  As vfio-ccw will
deal with everything at the subchannel level, provide space
for a single CRW to be transferred in one shot.

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: <20200505122745.53208-7-farman@linux.ibm.com>
[CH: added padding to ccw_crw_region]
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Farhan Ali
2020-05-05 14:27:43 +02:00
committed by Cornelia Huck
parent 4296151d23
commit d8cac29b1d
7 changed files with 118 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
Documentation/s390/vfio-ccw.rst
View File

@@ -298,6 +298,26 @@ 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 crw region
---------------------
The vfio-ccw crw region is used to return Channel Report Word (CRW)
data to userspace::
struct ccw_crw_region {
__u32 crw;
__u32 pad;
} __packed;
This region is exposed via region type VFIO_REGION_SUBTYPE_CCW_CRW.
Reading this region returns a CRW if one that is relevant for this
subchannel (e.g. one reporting changes in channel path state) is
pending, or all zeroes if not. If multiple CRWs are pending (including
possibly chained CRWs), reading this region again will return the next
one, until no more CRWs are pending and zeroes are returned. This is
similar to how STORE CHANNEL REPORT WORD works.
vfio-ccw operation details
--------------------------