| Message ID | 20190507081251.24307-1-cohuck@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,v2] s390/css: handle CCW_FLAG_SKIP | expand |
On 07/05/2019 10:12, Cornelia Huck wrote: > 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. > > Signed-off-by: Cornelia Huck <cohuck@redhat.com> > --- > > v1 -> v2: fixed checks for command type [Eric] > > Still only lightly tested (it boots); I don't think I have a tool > generating channel programs with the skip flag handy. > > --- > hw/s390x/css.c | 22 ++++++++++++++++++---- > include/hw/s390x/css.h | 1 + > 2 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > index 8fc9e35ba5d3..080ac7e5bc0b 100644 > --- a/hw/s390x/css.c > +++ b/hw/s390x/css.c > @@ -830,8 +830,12 @@ static int ccw_dstream_rw_noflags(CcwDataStream *cds, void *buff, int len, > if (op == CDS_OP_A) { > goto incr; > } > - ret = address_space_rw(&address_space_memory, cds->cda, > - MEMTXATTRS_UNSPECIFIED, buff, len, op); > + if (!cds->do_skip) { > + ret = address_space_rw(&address_space_memory, cds->cda, > + MEMTXATTRS_UNSPECIFIED, buff, len, op); > + } else { > + ret = 0; > + } > 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) { > - ret = address_space_rw(&address_space_memory, cds->cda, > - MEMTXATTRS_UNSPECIFIED, buff, iter_len, op); > + if (!cds->do_skip) { > + ret = address_space_rw(&address_space_memory, cds->cda, > + MEMTXATTRS_UNSPECIFIED, buff, iter_len, > + op); > + } else { > + ret = 0; > + } > 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 & CCW_CMD_BASIC_SENSE) == CCW_CMD_BASIC_SENSE || > + (ccw->cmd_code & 0x02) == 0x02 /* read */ || > + (ccw->cmd_code & 0x0c) == 0x0c /* read backwards */); I think you should use masks like ((code & 0x3) == 2) => READ ((code & 0xf) == 0xc) => READ BACKWARD ((code & 0xf) == 0x4) => SENSE Regards, Pierre > ccw_dstream_rewind(cds); > if (!(cds->flags & CDS_F_IDA)) { > cds->op_handler = ccw_dstream_rw_noflags; > diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h > index aae19c427229..7cc183ef4366 100644 > --- a/include/hw/s390x/css.h > +++ b/include/hw/s390x/css.h > @@ -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; > > /* >
On 5/7/19 5:08 AM, Pierre Morel wrote: > On 07/05/2019 10:12, Cornelia Huck wrote: >> 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. >> >> Signed-off-by: Cornelia Huck <cohuck@redhat.com> >> --- >> >> v1 -> v2: fixed checks for command type [Eric] >> >> Still only lightly tested (it boots); I don't think I have a tool >> generating channel programs with the skip flag handy. FWIW, my test program hits this code once (read of a single page, with SLI and SKIP flags set) before getting into the passthrough codepath. >> >> --- >> hw/s390x/css.c | 22 ++++++++++++++++++---- >> include/hw/s390x/css.h | 1 + >> 2 files changed, 19 insertions(+), 4 deletions(-) >> >> diff --git a/hw/s390x/css.c b/hw/s390x/css.c >> index 8fc9e35ba5d3..080ac7e5bc0b 100644 >> --- a/hw/s390x/css.c >> +++ b/hw/s390x/css.c >> @@ -830,8 +830,12 @@ static int ccw_dstream_rw_noflags(CcwDataStream >> *cds, void *buff, int len, >> if (op == CDS_OP_A) { >> goto incr; >> } >> - ret = address_space_rw(&address_space_memory, cds->cda, >> - MEMTXATTRS_UNSPECIFIED, buff, len, op); >> + if (!cds->do_skip) { >> + ret = address_space_rw(&address_space_memory, cds->cda, >> + MEMTXATTRS_UNSPECIFIED, buff, len, op); >> + } else { >> + ret = 0; >> + } >> 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) { >> - ret = address_space_rw(&address_space_memory, cds->cda, >> - MEMTXATTRS_UNSPECIFIED, buff, >> iter_len, op); >> + if (!cds->do_skip) { >> + ret = address_space_rw(&address_space_memory, cds->cda, >> + MEMTXATTRS_UNSPECIFIED, buff, >> iter_len, >> + op); >> + } else { >> + ret = 0; >> + } >> 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 & CCW_CMD_BASIC_SENSE) == CCW_CMD_BASIC_SENSE || >> + (ccw->cmd_code & 0x02) == 0x02 /* read */ || >> + (ccw->cmd_code & 0x0c) == 0x0c /* read backwards */); > > I think you should use masks like > ((code & 0x3) == 2) => READ > ((code & 0xf) == 0xc) => READ BACKWARD > ((code & 0xf) == 0x4) => SENSE I think Pierre is right. In the v2 code, a control CCW (like NOP) would still be flagged as a READ. > > Regards, > Pierre > > > > >> ccw_dstream_rewind(cds); >> if (!(cds->flags & CDS_F_IDA)) { >> cds->op_handler = ccw_dstream_rw_noflags; >> diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h >> index aae19c427229..7cc183ef4366 100644 >> --- a/include/hw/s390x/css.h >> +++ b/include/hw/s390x/css.h >> @@ -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; >> /* >> > >
On Tue, 7 May 2019 11:31:16 -0400 Eric Farman <farman@linux.ibm.com> wrote: > On 5/7/19 5:08 AM, Pierre Morel wrote: > > On 07/05/2019 10:12, Cornelia Huck wrote: > >> 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. > >> > >> Signed-off-by: Cornelia Huck <cohuck@redhat.com> > >> --- > >> > >> v1 -> v2: fixed checks for command type [Eric] > >> > >> Still only lightly tested (it boots); I don't think I have a tool > >> generating channel programs with the skip flag handy. > > FWIW, my test program hits this code once (read of a single page, with > SLI and SKIP flags set) before getting into the passthrough codepath. Ah, good. > > >> > >> --- > >> hw/s390x/css.c | 22 ++++++++++++++++++---- > >> include/hw/s390x/css.h | 1 + > >> 2 files changed, 19 insertions(+), 4 deletions(-) > >> > >> diff --git a/hw/s390x/css.c b/hw/s390x/css.c > >> index 8fc9e35ba5d3..080ac7e5bc0b 100644 > >> --- a/hw/s390x/css.c > >> +++ b/hw/s390x/css.c > >> @@ -830,8 +830,12 @@ static int ccw_dstream_rw_noflags(CcwDataStream > >> *cds, void *buff, int len, > >> if (op == CDS_OP_A) { > >> goto incr; > >> } > >> - ret = address_space_rw(&address_space_memory, cds->cda, > >> - MEMTXATTRS_UNSPECIFIED, buff, len, op); > >> + if (!cds->do_skip) { > >> + ret = address_space_rw(&address_space_memory, cds->cda, > >> + MEMTXATTRS_UNSPECIFIED, buff, len, op); > >> + } else { > >> + ret = 0; > >> + } > >> 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) { > >> - ret = address_space_rw(&address_space_memory, cds->cda, > >> - MEMTXATTRS_UNSPECIFIED, buff, > >> iter_len, op); > >> + if (!cds->do_skip) { > >> + ret = address_space_rw(&address_space_memory, cds->cda, > >> + MEMTXATTRS_UNSPECIFIED, buff, > >> iter_len, > >> + op); > >> + } else { > >> + ret = 0; > >> + } > >> 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 & CCW_CMD_BASIC_SENSE) == CCW_CMD_BASIC_SENSE || > >> + (ccw->cmd_code & 0x02) == 0x02 /* read */ || > >> + (ccw->cmd_code & 0x0c) == 0x0c /* read backwards */); > > > > I think you should use masks like > > ((code & 0x3) == 2) => READ > > ((code & 0xf) == 0xc) => READ BACKWARD > > ((code & 0xf) == 0x4) => SENSE > > I think Pierre is right. In the v2 code, a control CCW (like NOP) would > still be flagged as a READ. Sigh. I hope third time's the charm.
diff --git a/hw/s390x/css.c b/hw/s390x/css.c index 8fc9e35ba5d3..080ac7e5bc0b 100644 --- a/hw/s390x/css.c +++ b/hw/s390x/css.c @@ -830,8 +830,12 @@ static int ccw_dstream_rw_noflags(CcwDataStream *cds, void *buff, int len, if (op == CDS_OP_A) { goto incr; } - ret = address_space_rw(&address_space_memory, cds->cda, - MEMTXATTRS_UNSPECIFIED, buff, len, op); + if (!cds->do_skip) { + ret = address_space_rw(&address_space_memory, cds->cda, + MEMTXATTRS_UNSPECIFIED, buff, len, op); + } else { + ret = 0; + } 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) { - ret = address_space_rw(&address_space_memory, cds->cda, - MEMTXATTRS_UNSPECIFIED, buff, iter_len, op); + if (!cds->do_skip) { + ret = address_space_rw(&address_space_memory, cds->cda, + MEMTXATTRS_UNSPECIFIED, buff, iter_len, + op); + } else { + ret = 0; + } 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 & CCW_CMD_BASIC_SENSE) == CCW_CMD_BASIC_SENSE || + (ccw->cmd_code & 0x02) == 0x02 /* read */ || + (ccw->cmd_code & 0x0c) == 0x0c /* read backwards */); ccw_dstream_rewind(cds); if (!(cds->flags & CDS_F_IDA)) { cds->op_handler = ccw_dstream_rw_noflags; diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h index aae19c427229..7cc183ef4366 100644 --- a/include/hw/s390x/css.h +++ b/include/hw/s390x/css.h @@ -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; /*
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. Signed-off-by: Cornelia Huck <cohuck@redhat.com> --- v1 -> v2: fixed checks for command type [Eric] Still only lightly tested (it boots); I don't think I have a tool generating channel programs with the skip flag handy. --- hw/s390x/css.c | 22 ++++++++++++++++++---- include/hw/s390x/css.h | 1 + 2 files changed, 19 insertions(+), 4 deletions(-)