Re: [PATCH v1 4/4] s390x: Testing the Subchannel I/O read

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On 2019-11-14 18:09, Janosch Frank wrote:
On 11/14/19 5:38 PM, Pierre Morel wrote:
On 2019-11-14 10:15, Janosch Frank wrote:
On 11/13/19 1:23 PM, Pierre Morel wrote:
This simple test test the I/O reading by the SUB Channel by:
- initializing the Channel SubSystem with predefined CSSID:
    0xfe000000 CSSID for a Virtual CCW
    0x00090000 SSID for CCW-PONG
- initializing the ORB pointing to a single READ CCW
- starts the STSH command with the ORB
- Expect an interrupt
- writes the read data to output

The test implements lots of traces when DEBUG is on and
tests if memory above the stack is corrupted.
What happens if we do not habe the pong device?
CC error on stsch() which is currently not cached (but will in the next
version)

CC error on msch() and on ssch() which is cached and makes the test to fail.


Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
   lib/s390x/css.h      | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++
   lib/s390x/css_dump.c | 141 +++++++++++++++++++++++++++++
Hmm, what about splitting the patch into css.h/css_dump.c and the actual
test in s390x/css.c?
OK


   s390x/Makefile       |   2 +
   s390x/css.c          | 222 ++++++++++++++++++++++++++++++++++++++++++++++
   s390x/unittests.cfg  |   4 +
   5 files changed, 613 insertions(+)
   create mode 100644 lib/s390x/css.h
   create mode 100644 lib/s390x/css_dump.c
   create mode 100644 s390x/css.c

diff --git a/lib/s390x/css.h b/lib/s390x/css.h
new file mode 100644
OK to all comments...  (I sniped out for clarity)

...snip...


+static char buffer[4096];
+
+static void delay(int d)
+{
+	int i, j;
+
+	while (d--)
+		for (i = 1000000; i; i--)
+			for (j = 1000000; j; j--)
+				;
+}
You could set a timer.

Hum, do we really want to do this?
Why exactly do you need it if you can't have an exact time to wait for?

In fact I do not need it since the CCW instructions are treated synchronously.

It was for the fact we speak to a real device or if QEMU uses iothreads for CCW handling.


...snip


+
+	delay(1);
+
+	stsch(CSSID_PONG, &schib);
+	dump_schib(&schib);
Is all that dumping necessary or just a dev remainder?

it goes in the logs, so I thought it could be interresting to keep it.
Depends on how much output is produced.
If I have to scroll through your dumps to get to the ouptuts
  of the reports then they are .

See the answer below...


OK




+	DBG("got: %s\n", buffer);
+
+	return 0;
+}
+
+#define MAX_ERRORS 10
+static int checkmem(phys_addr_t start, phys_addr_t end)
+{
+	phys_addr_t curr;
+	int err = 0;
+
+	for (curr = start; curr != end; curr += PAGE_SIZE)
+		if (memcmp((void *)start, (void *)curr, PAGE_SIZE)) {
+			report("memcmp failed %lx", true, curr);
How many errors do you normally run into (hopefully 0)?

hopefully.

However I thought it could be interesting to know how many pages have
been dirtied.
Honestly, for debugging a failing test we would need to add prints or
attach gdb anyway. So I see no reason to not fail on the first occurrence.


OK

I will make the second version more quiet and much better.

Thanks for the comments,

Regards,

Pierre



--
Pierre Morel
IBM Lab Boeblingen




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