Re: [kvm-unit-tests PATCH v7 1/2] s390x: topology: Check the Perform Topology Function

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

On 3/23/23 16:45, Claudio Imbrenda wrote:
> On Mon, 20 Mar 2023 09:56:41 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> We check that the PTF instruction is working correctly when
>> the cpu topology facility is available.
>>
>> For KVM only, we test changing of the polarity between horizontal
>> and vertical and that a reset set the horizontal polarity.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> ---
>>   s390x/Makefile      |   1 +
>>   s390x/topology.c    | 180 ++++++++++++++++++++++++++++++++++++++++++++
>>   s390x/unittests.cfg |   3 +
>>   3 files changed, 184 insertions(+)
>>   create mode 100644 s390x/topology.c
>>
>> diff --git a/s390x/Makefile b/s390x/Makefile
>> index e94b720..05dac04 100644
>> --- a/s390x/Makefile
>> +++ b/s390x/Makefile
>> @@ -40,6 +40,7 @@ tests += $(TEST_DIR)/panic-loop-pgm.elf
>>   tests += $(TEST_DIR)/migration-sck.elf
>>   tests += $(TEST_DIR)/exittime.elf
>>   tests += $(TEST_DIR)/ex.elf
>> +tests += $(TEST_DIR)/topology.elf
>>   
>>   pv-tests += $(TEST_DIR)/pv-diags.elf
>>   
>> diff --git a/s390x/topology.c b/s390x/topology.c
>> new file mode 100644
>> index 0000000..ce248f1
>> --- /dev/null
>> +++ b/s390x/topology.c
>> @@ -0,0 +1,180 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * CPU Topology
>> + *
>> + * Copyright IBM Corp. 2022
>> + *
>> + * 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>
>> +#include <s390x/hardware.h>
>> +
>> +#define PTF_REQ_HORIZONTAL	0
>> +#define PTF_REQ_VERTICAL	1
>> +#define PTF_REQ_CHECK		2
>> +
>> +#define PTF_ERR_NO_REASON	0
>> +#define PTF_ERR_ALRDY_POLARIZED	1
>> +#define PTF_ERR_IN_PROGRESS	2
>> +
>> +extern int diag308_load_reset(u64);
>> +
>> +static int ptf(unsigned long fc, unsigned long *rc)
>> +{
>> +	int cc;
>> +
>> +	asm volatile(
>> +		"	ptf	%1	\n"
>> +		"       ipm     %0	\n"
>> +		"       srl     %0,28	\n"
>> +		: "=d" (cc), "+d" (fc)
>> +		:
>> +		: "cc");
>> +
>> +	*rc = fc >> 8;
>> +	return cc;
>> +}
>> +
>> +static void check_privilege(int fc)
>> +{
>> +	unsigned long rc;
>> +
>> +	report_prefix_push("Privilege");
>> +	report_info("function code %d", fc);
>> +	enter_pstate();
>> +	expect_pgm_int();
>> +	ptf(fc, &rc);
>> +	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
>> +	report_prefix_pop();
>> +}
>> +
>> +static void check_function_code(void)
>> +{
>> +	unsigned long rc;
>> +
>> +	report_prefix_push("Undefined fc");
>> +	expect_pgm_int();
>> +	ptf(0xff, &rc);
> please don't use magic numbers, add a new macro PTF_INVALID_FUNCTION
> (or something like that)

OK


>
>> +	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>> +	report_prefix_pop();
>> +}
>> +
>> +static void check_reserved_bits(void)
>> +{
>> +	unsigned long rc;
>> +
>> +	report_prefix_push("Reserved bits");
>> +	expect_pgm_int();
>> +	ptf(0xffffffffffffff00UL, &rc);
> I would like every single bit to be tested, since all of them are
> required to be zero.
>
> make a loop and test each, but please report success of failure only
> once at the end.
> use a report_info in case of failure to indicate which bit failed


OK


>
>> +	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>> +	report_prefix_pop();
>> +}
>> +
>> +static void check_mtcr_pending(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_REQ_CHECK, &rc);
>> +	cc = ptf(PTF_REQ_CHECK, &rc);
>> +	report(cc == 0, "PTF check should clear topology report");
>> +	report_prefix_pop();
>> +}
>> +
>> +static void check_polarization_change(void)
>> +{
>> +	unsigned long rc;
>> +	int cc;
>> +
>> +	report_prefix_push("Topology polarization check");
>> +
>> +	/* We expect a clean state through reset */
>> +	report(diag308_load_reset(1), "load normal reset done");
>> +
>> +	/*
>> +	 * Set vertical polarization to verify that RESET sets
>> +	 * horizontal polarization back.
>> +	 */
>> +	cc = ptf(PTF_REQ_VERTICAL, &rc);
>> +	report(cc == 0, "Set vertical polarization.");
>> +
>> +	report(diag308_load_reset(1), "load normal reset done");
>> +
>> +	cc = ptf(PTF_REQ_CHECK, &rc);
>> +	report(cc == 0, "Reset should clear topology report");
>> +
>> +	cc = ptf(PTF_REQ_HORIZONTAL, &rc);
>> +	report(cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED,
>> +	       "After RESET polarization is horizontal");
>> +
>> +	/* Flip between vertical and horizontal polarization */
>> +	cc = ptf(PTF_REQ_VERTICAL, &rc);
>> +	report(cc == 0, "Change to vertical polarization.");
> either here or in a new block, test that setting vertical twice in
> a row will also result in a cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED


OK


>
>> +
>> +	cc = ptf(PTF_REQ_CHECK, &rc);
>> +	report(cc == 1, "Polarization change should set topology report");
>> +
>> +	cc = ptf(PTF_REQ_HORIZONTAL, &rc);
>> +	report(cc == 0, "Change to horizontal polarization.");
> it cannot hurt to add here another check for pending reports


OK


Thanks for the comments,


Regards,

Pierre