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

Janosch Frank
2021-08-12T09:38:46Z

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
>