Re: [kvm-unit-tests PATCH v1 3/4] s390x: topology: check the Perform Topology Function

[Pierre Morel <pmorel@linux.ibm.com>]

On 8/9/21 12:12 PM, Janosch Frank wrote:
> On 8/9/21 10:48 AM, Pierre Morel wrote:
>> We check the PTF instruction.
>>
>> - We do not expect to support vertical polarization.
>>
>> - We do not expect the Modified Topology Change Report to be
>> pending or not at the moment the first PTF instruction with
>> PTF_CHECK function code is done as some code already did run
>> a polarization change may have occur.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> ---
>>   s390x/Makefile      |  1 +
>>   s390x/topology.c    | 87 +++++++++++++++++++++++++++++++++++++++++++++
>>   s390x/unittests.cfg |  3 ++
>>   3 files changed, 91 insertions(+)
>>   create mode 100644 s390x/topology.c
>>
>> diff --git a/s390x/Makefile b/s390x/Makefile
>> index 6565561b..c82b7dbf 100644
>> --- a/s390x/Makefile
>> +++ b/s390x/Makefile
>> @@ -24,6 +24,7 @@ tests += $(TEST_DIR)/mvpg.elf
>>   tests += $(TEST_DIR)/uv-host.elf
>>   tests += $(TEST_DIR)/edat.elf
>>   tests += $(TEST_DIR)/mvpg-sie.elf
>> +tests += $(TEST_DIR)/topology.elf
>>   
>>   tests_binary = $(patsubst %.elf,%.bin,$(tests))
>>   ifneq ($(HOST_KEY_DOCUMENT),)
>> diff --git a/s390x/topology.c b/s390x/topology.c
>> new file mode 100644
>> index 00000000..4146189a
>> --- /dev/null
>> +++ b/s390x/topology.c
>> @@ -0,0 +1,87 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * CPU Topology
>> + *
>> + * Copyright (c) 2021 IBM Corp
>> + *
>> + * Authors:
>> + *  Pierre Morel <pmorel@linux.ibm.com>
>> + */
>> +
>> +#include <libcflat.h>
>> +#include <asm/page.h>
>> +#include <asm/asm-offsets.h>
>> +#include <asm/interrupt.h>
>> +#include <asm/facility.h>
>> +#include <smp.h>
>> +#include <sclp.h>
>> +
>> +static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
> 
> We don't actually need that I made a mistake in stsi_get_fc().
> I'll comment in the other patch.

OK I saw.
thx

> 
>> +int machine_level;
>> +int mnest;
>> +
>> +#define PTF_HORIZONTAL	0
>> +#define PTF_VERTICAL	1
> 
> PTF_REQ_*

OK

> 
>> +#define PTF_CHECK	2> +
>> +#define PTF_ERR_NO_REASON	0
>> +#define PTF_ERR_ALRDY_POLARIZED	1
>> +#define PTF_ERR_IN_PROGRESS	2
>> +
>> +static int ptf(unsigned long fc, unsigned long *rc)
>> +{
>> +	int cc;
>> +
>> +	asm volatile(
>> +		"       .insn   rre,0xb9a20000,%1,%1\n"
>> +		"       ipm     %0\n"
>> +		"       srl     %0,28\n"
>> +		: "=d" (cc), "+d" (fc)
>> +		: "d" (fc)
>> +		: "cc");
>> +
>> +	*rc = fc >> 8;
>> +	return cc;
>> +}
>> +
>> +static void test_ptf(void)
>> +{
>> +	unsigned long rc;
>> +	int cc;
>> +
>> +	report_prefix_push("Topology Report pending");
>> +	/*
>> +	 * At this moment the topology may already have changed
>> +	 * since the VM has been started.
>> +	 * However, we can test if a second PTF instruction
>> +	 * reports that the topology did not change since the
>> +	 * preceding PFT instruction.
>> +	 */
>> +	ptf(PTF_CHECK, &rc);
>> +	cc = ptf(PTF_CHECK, &rc)> +	report(cc == 0, "PTF check clear");
> 
> Please leave a \n after a report for readability.
OK

> 
>> +	cc = ptf(PTF_HORIZONTAL, &rc);
>> +	report(cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED,
>> +	       "PTF horizontal already configured");
>> +	cc = ptf(PTF_VERTICAL, &rc);
>> +	report(cc == 2 && rc == PTF_ERR_NO_REASON,
>> +	       "PTF vertical non possible");
> 
> I've yet to look into your KVM/qemu code so I don't really understand
> what you're testing here and why we can expect to get those results.

In KVM please ignore the stupid patch 3 commented by Heiko and that will 
disappear.

It changes nothing to the first two patches.

OK, I will add some comments to explain what we await and why.

> 
> Maybe add a comment?
> Also what will happen if we start this test under LPAR or z/VM, will it
> fail?

The last one may fail, PTF would succeed AFAIU under LPAR.
For z/VM, no idea.


> 
>> +
>> +	report_prefix_pop();
>> +}
>> +
>> +int main(int argc, char *argv[])
>> +{
>> +	report_prefix_push("stsi");
> 
> Where did you copy that test from? :-)

:) yes cut and paste, I will change trhe prefix to "CPU Topology"

> 
>> +
>> +	if (!test_facility(11)) {
>> +		report_skip("Topology facility not present");
>> +		goto end;
>> +	}
>> +
>> +	report_info("Machine level %ld", stsi_get_fc(pagebuf));
>> +
>> +	test_ptf();
>> +end:
> 
> report_prefix_pop is missing here

Right.
will add.

> 
>> +	return report_summary();
>> +}
>> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
>> index 9e1802fd..0f84d279 100644
>> --- a/s390x/unittests.cfg
>> +++ b/s390x/unittests.cfg
>> @@ -109,3 +109,6 @@ file = edat.elf
>>   
>>   [mvpg-sie]
>>   file = mvpg-sie.elf
>> +
>> +[topology]
>> +file = topology.elf
>>
> 

Thanks,
Pierre

-- 
Pierre Morel
IBM Lab Boeblingen