Re: [kvm-unit-tests PATCH v2 3/4] s390x: topology: Check the Perform Topology Function

[Janosch Frank <frankja@linux.ibm.com>]

On 8/10/21 6:22 PM, Pierre Morel wrote:
> We check the PTF instruction.
> 
> - We do not expect to support vertical polarization.

KVM does not support vertical polarization and we don't expect it to be
added in the future?

> 
> - 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.

ENOPARSE

> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  s390x/Makefile      |  1 +
>  s390x/topology.c    | 99 +++++++++++++++++++++++++++++++++++++++++++++
>  s390x/unittests.cfg |  3 ++
>  3 files changed, 103 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..a0dc3b9e
> --- /dev/null
> +++ b/s390x/topology.c
> @@ -0,0 +1,99 @@
> +/* 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 int machine_level;
> +
> +#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
> +
> +static int ptf(unsigned long fc, unsigned long *rc)
> +{
> +	int cc;
> +
> +	asm volatile(
> +		"       .insn   rre,0xb9a20000,%1,0\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_REQ_CHECK, &rc);
> +	cc = ptf(PTF_REQ_CHECK, &rc);
> +	report(cc == 0, "PTF check clear");
> +
> +	/*
> +	 * In the LPAR we can not assume the state of the polarizatiom

polarization

> +	 * at this moment.
> +	 * Let's skip the tests for LPAR.
> +	 */

Any idea what happens on z/VM?
We don't necessarily need to support z/VM but we at least need to skip
like we do on lpar :-)

Maybe also add a TODO, so we know we could improve the test?

> +	if (machine_level < 3)
> +		goto end;
> +

Add comments:
We're always horizontally polarized in KVM.

> +	cc = ptf(PTF_REQ_HORIZONTAL, &rc);
> +	report(cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED,
> +	       "PTF horizontal already configured");
> +

KVM doesn't support vertical polarization.

> +	cc = ptf(PTF_REQ_VERTICAL, &rc);
> +	report(cc == 2 && rc == PTF_ERR_NO_REASON,
> +	       "PTF vertical non possible");

s/non/not/

> +
> +end:
> +	report_prefix_pop();
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	report_prefix_push("CPU Topology");
> +
> +	if (!test_facility(11)) {
> +		report_skip("Topology facility not present");
> +		goto end;
> +	}
> +
> +	machine_level = stsi_get_fc();
> +	report_info("Machine level %d", machine_level);
> +
> +	test_ptf();
> +
> +end:
> +	report_prefix_pop();
> +	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
>