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

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

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)

> +	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

> +	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

> +
> +	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

> +
> +	report_prefix_pop();
> +}
> +
> +static void test_ptf(void)
> +{
> +	check_privilege(PTF_REQ_HORIZONTAL);
> +	check_privilege(PTF_REQ_VERTICAL);
> +	check_privilege(PTF_REQ_CHECK);
> +	check_function_code();
> +	check_reserved_bits();
> +	check_mtcr_pending();
> +	check_polarization_change();
> +}
> +
> +static struct {
> +	const char *name;
> +	void (*func)(void);
> +} tests[] = {
> +	{ "PTF", test_ptf},
> +	{ NULL, NULL }
> +};
> +
> +int main(int argc, char *argv[])
> +{
> +	int i;
> +
> +	report_prefix_push("CPU Topology");
> +
> +	if (!test_facility(11)) {
> +		report_skip("Topology facility not present");
> +		goto end;
> +	}
> +
> +	report_info("Virtual machine level %ld", stsi_get_fc());
> +
> +	for (i = 0; tests[i].name; i++) {
> +		report_prefix_push(tests[i].name);
> +		tests[i].func();
> +		report_prefix_pop();
> +	}
> +
> +end:
> +	report_prefix_pop();
> +	return report_summary();
> +}
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index 453ee9c..d0ac683 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -233,3 +233,6 @@ extra_params = -append '--parallel'
>  
>  [execute]
>  file = ex.elf
> +
> +[topology]
> +file = topology.elf