On 7/8/20 5:00 PM, Thomas Huth wrote:
> When running the kvm-unit-tests with TCG on s390x, the cpumodel test
> always reports the error about the missing DFP (decimal floating point)
> facility. This is kind of expected, since DFP is not required for
> running Linux and thus nobody is really interested in implementing
> this facility in TCG. Thus let's mark this as an expected error instead,
> so that we can run the kvm-unit-tests also with TCG without getting
> test failures that we do not care about.
>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
Acked-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> v3:
> - Moved the is_tcg() function to the library so that it can be used
> later by other tests, too
> - Make sure to call alloc_page() and stsi() only once
>
> v2:
> - Rewrote the logic, introduced expected_tcg_fail flag
> - Use manufacturer string instead of VM name to detect TCG
>
> lib/s390x/vm.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> lib/s390x/vm.h | 14 ++++++++++++++
> s390x/Makefile | 1 +
> s390x/cpumodel.c | 19 +++++++++++++------
> 4 files changed, 74 insertions(+), 6 deletions(-)
> create mode 100644 lib/s390x/vm.c
> create mode 100644 lib/s390x/vm.h
>
> diff --git a/lib/s390x/vm.c b/lib/s390x/vm.c
> new file mode 100644
> index 0000000..c852713
> --- /dev/null
> +++ b/lib/s390x/vm.c
> @@ -0,0 +1,46 @@
> +/*
> + * Functions to retrieve VM-specific information
> + *
> + * Copyright (c) 2020 Red Hat Inc
> + *
> + * Authors:
> + * Thomas Huth <thuth@xxxxxxxxxx>
> + *
> + * SPDX-License-Identifier: LGPL-2.1-or-later
> + */
> +
> +#include <libcflat.h>
> +#include <alloc_page.h>
> +#include <asm/arch_def.h>
> +#include "vm.h"
> +
> +/**
> + * Detect whether we are running with TCG (instead of KVM)
> + */
> +bool vm_is_tcg(void)
> +{
> + const char qemu_ebcdic[] = { 0xd8, 0xc5, 0xd4, 0xe4 };
> + static bool initialized = false;
> + static bool is_tcg = false;
> + uint8_t *buf;
> +
> + if (initialized)
> + return is_tcg;
> +
> + buf = alloc_page();
> + if (!buf)
> + return false;
> +
> + if (stsi(buf, 1, 1, 1))
> + goto out;
> +
> + /*
> + * If the manufacturer string is "QEMU" in EBCDIC, then we
> + * are on TCG (otherwise the string is "IBM" in EBCDIC)
> + */
> + is_tcg = !memcmp(&buf[32], qemu_ebcdic, sizeof(qemu_ebcdic));
> + initialized = true;
> +out:
> + free_page(buf);
> + return is_tcg;
> +}
> diff --git a/lib/s390x/vm.h b/lib/s390x/vm.h
> new file mode 100644
> index 0000000..33008d8
> --- /dev/null
> +++ b/lib/s390x/vm.h
> @@ -0,0 +1,14 @@
> +/*
> + * Functions to retrieve VM-specific information
> + *
> + * Copyright (c) 2020 Red Hat Inc
> + *
> + * SPDX-License-Identifier: LGPL-2.1-or-later
> + */
> +
> +#ifndef S390X_VM_H
> +#define S390X_VM_H
> +
> +bool vm_is_tcg(void);
> +
> +#endif /* S390X_VM_H */
> diff --git a/s390x/Makefile b/s390x/Makefile
> index ddb4b48..98ac29e 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -51,6 +51,7 @@ cflatobjs += lib/s390x/sclp-console.o
> cflatobjs += lib/s390x/interrupt.o
> cflatobjs += lib/s390x/mmu.o
> cflatobjs += lib/s390x/smp.o
> +cflatobjs += lib/s390x/vm.o
>
> OBJDIRS += lib/s390x
>
> diff --git a/s390x/cpumodel.c b/s390x/cpumodel.c
> index 5d232c6..116a966 100644
> --- a/s390x/cpumodel.c
> +++ b/s390x/cpumodel.c
> @@ -11,14 +11,19 @@
> */
>
> #include <asm/facility.h>
> +#include <vm.h>
>
> -static int dep[][2] = {
> +static struct {
> + int facility;
> + int implied;
> + bool expected_tcg_fail;
> +} dep[] = {
> /* from SA22-7832-11 4-98 facility indications */
> { 4, 3 },
> { 5, 3 },
> { 5, 4 },
> { 19, 18 },
> - { 37, 42 },
> + { 37, 42, true }, /* TCG does not have DFP and won't get it soon */
> { 43, 42 },
> { 73, 49 },
> { 134, 129 },
> @@ -46,11 +51,13 @@ int main(void)
>
> report_prefix_push("dependency");
> for (i = 0; i < ARRAY_SIZE(dep); i++) {
> - if (test_facility(dep[i][0])) {
> - report(test_facility(dep[i][1]), "%d implies %d",
> - dep[i][0], dep[i][1]);
> + if (test_facility(dep[i].facility)) {
> + report_xfail(dep[i].expected_tcg_fail && vm_is_tcg(),
> + test_facility(dep[i].implied),
> + "%d implies %d",
> + dep[i].facility, dep[i].implied);
> } else {
> - report_skip("facility %d not present", dep[i][0]);
> + report_skip("facility %d not present", dep[i].facility);
> }
> }
> report_prefix_pop();
>
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