Re: [kvm-unit-tests PATCH v2 6/9] s390x: css: stsch, enumeration test

Pierre Morel
2019-12-02T17:53:23Z

On 2019-12-02 15:22, Cornelia Huck wrote:
> On Thu, 28 Nov 2019 13:46:04 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> First step by testing the channel subsystem is to enumerate the css and
>
> s/by/for/

ok

>
>> retrieve the css devices.
>>
>> This test the success of STSCH I/O instruction.
>
> s/test/tests/

yes

>
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> ---
>> s390x/Makefile | 4 ++-
>> s390x/css.c | 86 +++++++++++++++++++++++++++++++++++++++++++++
>> s390x/unittests.cfg | 4 +++
>> 3 files changed, 93 insertions(+), 1 deletion(-)
>> create mode 100644 s390x/css.c
>>
>
> (...)
>
>> diff --git a/s390x/css.c b/s390x/css.c
>> new file mode 100644
>> index 0000000..8186f55
>> --- /dev/null
>> +++ b/s390x/css.c
>> @@ -0,0 +1,86 @@
>> +/*
>> + * Channel Sub-System tests
>
> s/Sub-System/Subsystem/

yes too

>
>> + *
>> + * Copyright (c) 2019 IBM Corp
>> + *
>> + * Authors:
>> + * Pierre Morel <pmorel@linux.ibm.com>
>> + *
>> + * This code is free software; you can redistribute it and/or modify it
>> + * under the terms of the GNU General Public License version 2.
>> + */
>> +
>> +#include <libcflat.h>
>> +
>> +#include <css.h>
>> +
>> +#define SID_ONE 0x00010000
>> +
>> +static struct schib schib;
>> +
>> +static const char *Channel_type[3] = {
>> + "I/O", "CHSC", "MSG"
>
> No EADM? :)

I forgot EADM, I will add it!

>
> I don't think we plan to emulate anything beyond I/O in QEMU, though.

Even, yes, no plan to use it for now.

>
>> +};
>> +
>> +static int test_device_sid;
>> +
>> +static void test_enumerate(void)
>> +{
>> + struct pmcw *pmcw = &schib.pmcw;
>> + int sid;
>> + int ret, i;
>> + int found = 0;
>> +
>> + for (sid = 0; sid < 0xffff; sid++) {
>> + ret = stsch(sid|SID_ONE, &schib);
>
> This seems a bit odd. You are basically putting the subchannel number
> into sid, OR in the one, and then use the resulting value as the sid
> (subchannel identifier).
>
>> + if (!ret && (pmcw->flags & PMCW_DNV)) {
>> + report_info("SID %04x Type %s PIM %x", sid,
>
> That's not a sid, but the subchannel number (see above).
>
>> + Channel_type[pmcw->st], pmcw->pim);
>> + for (i = 0; i < 8; i++) {
>> + if ((pmcw->pim << i) & 0x80) {
>> + report_info("CHPID[%d]: %02x", i,
>> + pmcw->chpid[i]);
>> + break;
>> + }
>> + }
>> + found++;
>> +
>> + }
>
> Here, you iterate over the 0-0xffff range, even if you got a condition
> code 3 (indicating no more subchannels in that set). Is that
> intentional?

I thought there could be more subchannels.
I need then a break in the loop when this happens.
I will reread the PoP to see how to find that no more subchannel are in
that set.

>
>> + if (found && !test_device_sid)
>> + test_device_sid = sid|SID_ONE;
>
> You set test_device_sid to the last valid subchannel? Why?

The last ? I wanted the first one

I wanted something easy but I should have explain.

To avoid doing complicated things like doing a sense on each valid
subchannel I just take the first one.
Should be enough as we do not go to the device in this test.

>
>> + }
>> + if (!found) {
>> + report("Found %d devices", 0, found);
>> + return;
>> + }
>> + ret = stsch(test_device_sid, &schib);
>
> Why do you do a stsch() again?

right, no need.
In an internal version I used to print some informations from the SCHIB.
Since in between I overwrote the SHIB, I did it again.
But in this version; no need.

>
>> + if (ret) {
>> + report("Err %d on stsch on sid %08x", 0, ret, test_device_sid);
>> + return;
>> + }
>> + report("Tested", 1);
>> + return;
>
> I don't think you need this return statement.

right I have enough work. :)

>
> Your test only enumerates devices in the first subchannel set. Do you
> plan to enhance the test to enable the MSS facility and iterate over
> all subchannel sets?

Yes, it is something we can do in a following series

>
>> +}
>> +
>> +static struct {
>> + const char *name;
>> + void (*func)(void);
>> +} tests[] = {
>> + { "enumerate (stsch)", test_enumerate },
>> + { NULL, NULL }
>> +};
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + int i;
>> +
>> + report_prefix_push("Channel Sub-System");
>
> s/Sub-System/Subsystem/

yes, again.

Thanks for the review.
Regards,

Pierre

--
Pierre Morel
IBM Lab Boeblingen