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author | Cornelia Huck <cohuck@redhat.com> | 2020-04-07 13:16:05 +0200 |
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committer | Cornelia Huck <cohuck@redhat.com> | 2020-06-02 13:14:08 +0200 |
commit | 430220b0bbcbaaaa03718111ff541ee8cd97c781 (patch) | |
tree | 4ee362bb1b66b3dcfa42f015b1701788b20ac81e /Documentation | |
parent | 725b94d74128cd208bfdd446ad6b5f4b38cf5395 (diff) | |
download | linux-stable-430220b0bbcbaaaa03718111ff541ee8cd97c781.tar.gz linux-stable-430220b0bbcbaaaa03718111ff541ee8cd97c781.tar.bz2 linux-stable-430220b0bbcbaaaa03718111ff541ee8cd97c781.zip |
vfio-ccw: document possible errors
Interacting with the I/O and the async regions can yield a number
of errors, which had been undocumented so far. These are part of
the api, so remedy that.
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20200407111605.1795-1-cohuck@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/s390/vfio-ccw.rst | 56 |
1 files changed, 54 insertions, 2 deletions
diff --git a/Documentation/s390/vfio-ccw.rst b/Documentation/s390/vfio-ccw.rst index 23e7d136f8b4..3a946fd45562 100644 --- a/Documentation/s390/vfio-ccw.rst +++ b/Documentation/s390/vfio-ccw.rst @@ -204,15 +204,44 @@ definition of the region is:: __u32 ret_code; } __packed; +This region is always available. + While starting an I/O request, orb_area should be filled with the guest ORB, and scsw_area should be filled with the SCSW of the Virtual Subchannel. irb_area stores the I/O result. -ret_code stores a return code for each access of the region. +ret_code stores a return code for each access of the region. The following +values may occur: + +``0`` + The operation was successful. + +``-EOPNOTSUPP`` + The orb specified transport mode or an unidentified IDAW format, or the + scsw specified a function other than the start function. + +``-EIO`` + A request was issued while the device was not in a state ready to accept + requests, or an internal error occurred. + +``-EBUSY`` + The subchannel was status pending or busy, or a request is already active. + +``-EAGAIN`` + A request was being processed, and the caller should retry. + +``-EACCES`` + The channel path(s) used for the I/O were found to be not operational. + +``-ENODEV`` + The device was found to be not operational. + +``-EINVAL`` + The orb specified a chain longer than 255 ccws, or an internal error + occurred. -This region is always available. vfio-ccw cmd region ------------------- @@ -231,6 +260,29 @@ This region is exposed via region type VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD. Currently, CLEAR SUBCHANNEL and HALT SUBCHANNEL use this region. +command specifies the command to be issued; ret_code stores a return code +for each access of the region. The following values may occur: + +``0`` + The operation was successful. + +``-ENODEV`` + The device was found to be not operational. + +``-EINVAL`` + A command other than halt or clear was specified. + +``-EIO`` + A request was issued while the device was not in a state ready to accept + requests. + +``-EAGAIN`` + A request was being processed, and the caller should retry. + +``-EBUSY`` + The subchannel was status pending or busy while processing a halt request. + + vfio-ccw operation details -------------------------- |