On Tue, 5 Sep 2017 13:16:44 +0200
Halil Pasic <pa...@linux.vnet.ibm.com> wrote:
> Let's add indirect data addressing support for our virtual channel
> subsystem. This implementation does no prefetching, but steps
> trough the idal as we go.
>
> Signed-off-by: Halil Pasic <pa...@linux.vnet.ibm.com>
> ---
> hw/s390x/css.c | 110
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 109 insertions(+), 1 deletion(-)
>
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index c1bc9944e6..9d8f9fd7ea 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -819,6 +819,114 @@ incr:
> return 0;
> }
>
> +/* retuns values between 1 and bs, where bs is a power of 2 */
'bs' is 'block size'?
> +static inline uint16_t ida_continuous_left(hwaddr cda, uint64_t bs)
> +{
> + return bs - (cda & (bs - 1));
> +}
> +
> +static inline uint64_t ccw_ida_block_size(uint8_t flags)
> +{
> + return 1ULL << (((flags ^ CDS_F_C64) & (CDS_F_C64 | CDS_F_I2K)) ? 11 :
> 12);
> +}
> +
> +static inline int ida_read_next_idaw(CcwDataStream *cds)
> +{
> + union {uint64_t fmt2; uint32_t fmt1; } idaw;
> + bool is_fmt2 = cds->flags & CDS_F_C64;
> + int ret;
> + hwaddr idaw_addr;
> +
> + if (is_fmt2) {
> + idaw_addr = cds->cda_orig + sizeof(idaw.fmt2) * cds->at_idaw;
> + if (idaw_addr & 0x07) {
> + return -EINVAL; /* chanel program check */
How fashionable ;)
[s/chanel/channel/ :D]
> + }
> + ret = address_space_rw(&address_space_memory, idaw_addr,
> + MEMTXATTRS_UNSPECIFIED, (void *) &idaw.fmt2,
> + sizeof(idaw.fmt2), false);
> + cds->cda = be64_to_cpu(idaw.fmt2);
> + } else {
> + idaw_addr = cds->cda_orig + sizeof(idaw.fmt1) * cds->at_idaw;
> + if (idaw_addr & 0x03) {
> + return -EINVAL; /* chanel program check */
> +
> + }
> + ret = address_space_rw(&address_space_memory, idaw_addr,
> + MEMTXATTRS_UNSPECIFIED, (void *) &idaw.fmt1,
> + sizeof(idaw.fmt1), false);
> + cds->cda = be64_to_cpu(idaw.fmt1);
> + }
> + ++(cds->at_idaw);
> + if (ret != MEMTX_OK) {
> + /* assume inaccessible address */
> + return -EINVAL; /* chanel program check */
> +
> + }
> + return 0;
> +}
> +
> +static int ccw_dstream_rw_ida(CcwDataStream *cds, void *buff, int len,
> + CcwDataStreamOp op)
> +{
> + uint64_t bs = ccw_ida_block_size(cds->flags);
> + int ret = 0;
> + uint16_t cont_left, iter_len;
> +
> + ret = cds_check_len(cds, len);
> + if (ret <= 0) {
> + return ret;
> + }
> + if (!cds->at_idaw) {
> + /* read first idaw */
> + ret = ida_read_next_idaw(cds);
> + if (ret) {
> + goto err;
> + }
> + cont_left = ida_continuous_left(cds->cda, bs);
> + } else {
> + cont_left = ida_continuous_left(cds->cda, bs);
> + if (cont_left == bs) {
> + ret = ida_read_next_idaw(cds);
> + if (ret) {
> + goto err;
> + }
> + if (cds->cda & (bs - 1)) {
> + ret = -EINVAL; /* chanel program check */
> + goto err;
> + }
> + }
> + }
> +do_iter_len:
> + iter_len = MIN(len, cont_left);
> + if (op == CDS_OP_A) {
> + goto incr;
> + }
> + ret = address_space_rw(&address_space_memory, cds->cda,
> + MEMTXATTRS_UNSPECIFIED, buff, iter_len, op);
> + if (ret != MEMTX_OK) {
> + /* assume inaccessible address */
> + ret = -EINVAL; /* chanel program check */
> + goto err;
> + }
> +incr:
> + cds->at_byte += iter_len;
> + cds->cda += iter_len;
> + len -= iter_len;
> + if (len) {
> + ret = ida_read_next_idaw(cds);
> + if (ret) {
> + goto err;
> + }
> + cont_left = bs;
> + goto do_iter_len;
> + }
> + return ret;
> +err:
> + cds->flags |= CDS_F_STREAM_BROKEN;
> + return ret;
> +}
I'm not so happy about the many gotos (excepting the err ones). Any
chance to get around these?
> +
> void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb)
> {
> /*
> @@ -835,7 +943,7 @@ void ccw_dstream_init(CcwDataStream *cds, CCW1 const
> *ccw, ORB const *orb)
> if (!(cds->flags & CDS_F_IDA)) {
> cds->op_handler = ccw_dstream_rw_noflags;
> } else {
> - assert(false);
> + cds->op_handler = ccw_dstream_rw_ida;
> }
> }
>
