On 09/20/2017 10:33 AM, Cornelia Huck wrote:
> On Wed, 20 Sep 2017 15:42:38 +0800
> Dong Jia Shi <bjsdj...@linux.vnet.ibm.com> wrote:
>
>> * Halil Pasic <pa...@linux.vnet.ibm.com> [2017-09-19 20:27:45 +0200]:
>>
>>> Let's add indirect data addressing support for our virtual channel
>>> subsystem. This implementation does not bother with any kind of
>>> prefetching. We simply step through the IDAL on demand.
>>>
>>> Signed-off-by: Halil Pasic <pa...@linux.vnet.ibm.com>
>>> Signed-off-by: Cornelia Huck <coh...@redhat.com>
>>> ---
>>> hw/s390x/css.c | 117
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 116 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
>>> index 2d37a9ddde..a3ce6d89b6 100644
>>> --- a/hw/s390x/css.c
>>> +++ b/hw/s390x/css.c
>>> @@ -827,6 +827,121 @@ incr:
>>> return 0;
>>> }
>>>
>>> +/* returns values between 1 and bsz, where bsz is a power of 2 */
>>> +static inline uint16_t ida_continuous_left(hwaddr cda, uint64_t bsz)
>>> +{
>>> + return bsz - (cda & (bsz - 1));
>>> +}
>>> +
>>> +static inline uint64_t ccw_ida_block_size(uint8_t flags)
>>> +{
>>> + if ((flags & CDS_F_C64) && !(flags & CDS_F_I2K)) {
>>> + return 1ULL << 12;
>>> + }
>>> + return 1ULL << 11;
>>> +}
>>> +
>>> +static inline int ida_read_next_idaw(CcwDataStream *cds, bool ccw_fmt1,
>>> + bool idaw_fmt_2)
>>> +{
>>> + union {uint64_t fmt2; uint32_t fmt1; } idaw;
>>> + int ret;
>>> + hwaddr idaw_addr;
>>> +
>>> + if (idaw_fmt_2) {
>>> + idaw_addr = cds->cda_orig + sizeof(idaw.fmt2) * cds->at_idaw;
>>> + if (idaw_addr & 0x07 && cds_ccw_addrs_ok(idaw_addr, 0, ccw_fmt1)) {
>>> + return -EINVAL; /* channel program check */
>>> + }
>>> + ret = address_space_rw(&address_space_memory, idaw_addr,
>> Ahh, just got one question here:
>> Do we need to considerate endianess for idaw_addr?
>
> That is taken care of below.
>
> And the previous version worked on my laptop via tcg ;)
Nod.
>
>>
>>> + 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 && cds_ccw_addrs_ok(idaw_addr, 0, ccw_fmt1)) {
>>> + return -EINVAL; /* channel 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);
>> Still need to check bit 0x80000000 here I think.
>
> Yes, I think this is 'must be zero' for format-1 idaws, and not covered
> by the ccw-format specific checks above. (Although the PoP can be a bit
> confusing with many similar terms...)
>
It's taken care of in ccw_dstream_rw_ida before the actual
access happens. Code looks like this:
+ if (!idaw_fmt2 && (cds->cda + iter_len) >= (1ULL << 31)) {
+ ret = -EINVAL; /* channel program check */
+ goto err;
+ }
The idea was to have it similar to the non-indirect case.
>>
>>> + }
>>> + ++(cds->at_idaw);
>>> + if (ret != MEMTX_OK) {
>>> + /* assume inaccessible address */
>>> + return -EINVAL; /* channel program check */
>>> +
>> Extra line.
>>
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +static int ccw_dstream_rw_ida(CcwDataStream *cds, void *buff, int len,
>>> + CcwDataStreamOp op)
>>> +{
>>> + uint64_t bsz = ccw_ida_block_size(cds->flags);
>>> + int ret = 0;
>>> + uint16_t cont_left, iter_len;
>>> + const bool idaw_fmt2 = cds->flags & CDS_F_C64;
>>> + bool ccw_fmt1 = cds->flags & CDS_F_FMT;
>> Use 'const bool' either? Although I doubt the value of using const here.
>> ;)
>
> Both being the same is still a good idea.
>
Yeah. For which one should I go (with const or without)?
>>
>>> +
>>> + ret = cds_check_len(cds, len);
>>> + if (ret <= 0) {
>>> + return ret;
>>> + }
>>
>> [...]
>>
>
