* [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP
@ 2019-05-07 8:12 Cornelia Huck
2019-05-07 9:08 ` Pierre Morel
0 siblings, 1 reply; 4+ messages in thread
From: Cornelia Huck @ 2019-05-07 8:12 UTC (permalink / raw)
To: Halil Pasic, Christian Borntraeger
Cc: Eric Farman, qemu-s390x, Cornelia Huck, qemu-devel
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 */);
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;
/*
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP
2019-05-07 8:12 [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP Cornelia Huck
@ 2019-05-07 9:08 ` Pierre Morel
2019-05-07 15:31 ` Eric Farman
0 siblings, 1 reply; 4+ messages in thread
From: Pierre Morel @ 2019-05-07 9:08 UTC (permalink / raw)
To: Cornelia Huck, Halil Pasic, Christian Borntraeger
Cc: Eric Farman, qemu-s390x, qemu-devel
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;
>
> /*
>
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP
2019-05-07 9:08 ` Pierre Morel
@ 2019-05-07 15:31 ` Eric Farman
2019-05-08 8:44 ` Cornelia Huck
0 siblings, 1 reply; 4+ messages in thread
From: Eric Farman @ 2019-05-07 15:31 UTC (permalink / raw)
To: pmorel, Cornelia Huck, Halil Pasic, Christian Borntraeger
Cc: qemu-s390x, qemu-devel
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;
>> /*
>>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP
2019-05-07 15:31 ` Eric Farman
@ 2019-05-08 8:44 ` Cornelia Huck
0 siblings, 0 replies; 4+ messages in thread
From: Cornelia Huck @ 2019-05-08 8:44 UTC (permalink / raw)
To: Eric Farman
Cc: Halil Pasic, Christian Borntraeger, qemu-s390x, qemu-devel, pmorel
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.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-05-08 8:44 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-05-07 8:12 [Qemu-devel] [PATCH RFC v2] s390/css: handle CCW_FLAG_SKIP Cornelia Huck
2019-05-07 9:08 ` Pierre Morel
2019-05-07 15:31 ` Eric Farman
2019-05-08 8:44 ` Cornelia Huck
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