Commit 85fa94e1 authored by Cornelia Huck's avatar Cornelia Huck
Browse files

s390/css: handle CCW_FLAG_SKIP 



If a ccw has CCW_FLAG_SKIP set, and the command is of type
read, read backwards, or sense, no data should be written
to the guest for that command.

Reviewed-by: default avatarEric Farman <farman@linux.ibm.com>
Message-Id: <20190516133327.11430-1-cohuck@redhat.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 1e3f9c69

hw/s390x/css.c

+18 −4
Original line number Diff line number Diff line
@@ -830,8 +830,12 @@ static int ccw_dstream_rw_noflags(CcwDataStream *cds, void *buff, int len, 
    if (op == CDS_OP_A) {

        goto incr;

    }

    if (!cds->do_skip) {

        ret = address_space_rw(&address_space_memory, cds->cda,

                               MEMTXATTRS_UNSPECIFIED, buff, len, op);

    } else {

        ret = MEMTX_OK;

    }

    if (ret != MEMTX_OK) {

        cds->flags |= CDS_F_STREAM_BROKEN;

        return -EINVAL;
@@ -928,8 +932,13 @@ static int ccw_dstream_rw_ida(CcwDataStream *cds, void *buff, int len, 
    do {

        iter_len = MIN(len, cont_left);

        if (op != CDS_OP_A) {

            if (!cds->do_skip) {

                ret = address_space_rw(&address_space_memory, cds->cda,

                                   MEMTXATTRS_UNSPECIFIED, buff, iter_len, op);

                                       MEMTXATTRS_UNSPECIFIED, buff, iter_len,

                                       op);

            } else {

                ret = MEMTX_OK;

            }

            if (ret != MEMTX_OK) {

                /* assume inaccessible address */

                ret = -EINVAL; /* channel program check */
@@ -968,6 +977,11 @@ void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb) 


    cds->count = ccw->count;

    cds->cda_orig = ccw->cda;

    /* skip is only effective for read, read backwards, or sense commands */

    cds->do_skip = (ccw->flags & CCW_FLAG_SKIP) &&

        ((ccw->cmd_code & 0x0f) == CCW_CMD_BASIC_SENSE ||

         (ccw->cmd_code & 0x03) == 0x02 /* read */ ||

         (ccw->cmd_code & 0x0f) == 0x0c /* read backwards */);

    ccw_dstream_rewind(cds);

    if (!(cds->flags & CDS_F_IDA)) {

        cds->op_handler = ccw_dstream_rw_noflags;

include/hw/s390x/css.h

+1 −0
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ typedef struct CcwDataStream { 
    int (*op_handler)(struct CcwDataStream *cds, void *buff, int len,

                      CcwDataStreamOp op);

    hwaddr cda;

    bool do_skip;

} CcwDataStream;



/*