• Harald Freudenberger's avatar
    s390/ap: add ap status asynch error support · 038c5bed
    Harald Freudenberger authored
    Review and extend the low level AP code to be able to
    deal with asynchronous reported errors on APQNs.
    
    The hypervisor and the SE guest may be confronted with
    an asynchronously reported error at return of an AP
    instruction. So all places where AP instructions are
    called need review and may eventually need extensions.
    However, not all places need rework. As together with
    the AP status and the enabled asynch bit there is always
    a response code set. The asynch error reporting comes
    with new response codes which may be simple handled in
    the default case of a switch statement.
    
    The idea behind this patch is to report asynch errors
    as -EPERM (read this as "Operation not permitted") which
    reflects the fact that only a rapq (with F bit enabled)
    is a valid AP instruction when an asynch error is flagged.
    
    The AP queue state machine functions return
    AP_SM_WAIT_NONE when a asynch error is detected to reflect
    the fact, that the state machine can't do anything with
    such an error as long as the queue is reset.
    
    Unfortunately the ap bus scan function needed some
    update as the ap_queue_info() now needs to return
    3 states: 1 if an APQN exists and info is available,
    -1 if it is assumed an APQN does not exist and the new
    return value 0 without any info values filled. This 0
    returncode is handled as "there is an APQN but we currently
    don't know any more hw info about this, so please use
    your previous info and try again later".
    Signed-off-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
    Reviewed-by: default avatarHolger Dengler <dengler@linux.ibm.com>
    Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
    038c5bed
ap_queue.c 31.5 KB