Re: [kvm-unit-tests PATCH v1 3/3] s390x: add pgm spec interrupt loop test

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

On 6/30/22 13:30, Nico Boehr wrote:
> An invalid PSW causes a program interrupt. When an invalid PSW is
> introduced in the pgm_new_psw, an interrupt loop occurs as soon as a
> program interrupt is caused.
> 
> QEMU should detect that and panick the guest, hence add a test for it.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Test is fine but the same general comments as in patch #2 apply.

> ---
>   s390x/Makefile      |  1 +
>   s390x/pgmint-loop.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
>   s390x/unittests.cfg |  4 ++++
>   3 files changed, 51 insertions(+)
>   create mode 100644 s390x/pgmint-loop.c
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 92a020234c9f..a600dbfb3f4c 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -35,6 +35,7 @@ tests += $(TEST_DIR)/pv-attest.elf
>   tests += $(TEST_DIR)/migration-cmm.elf
>   tests += $(TEST_DIR)/migration-skey.elf
>   tests += $(TEST_DIR)/extint-loop.elf
> +tests += $(TEST_DIR)/pgmint-loop.elf
>   
>   pv-tests += $(TEST_DIR)/pv-diags.elf
>   
> diff --git a/s390x/pgmint-loop.c b/s390x/pgmint-loop.c
> new file mode 100644
> index 000000000000..5b74f26dbc3d
> --- /dev/null
> +++ b/s390x/pgmint-loop.c
> @@ -0,0 +1,46 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Program interrupt loop test
> + *
> + * Copyright IBM Corp. 2022
> + *
> + * Authors:
> + *  Nico Boehr <nrb@linux.ibm.com>
> + */
> +#include <libcflat.h>
> +#include <bitops.h>
> +#include <asm/interrupt.h>
> +#include <asm/barrier.h>
> +
> +static void pgm_int_handler(void)
> +{
> +	/*
> +	 * return to pgm_old_psw. This gives us the chance to print the return_fail
> +	 * in case something goes wrong.
> +	 */
> +	asm volatile (
> +		"lpswe %[pgm_old_psw]\n"
> +		:
> +		: [pgm_old_psw] "Q"(lowcore.pgm_old_psw)
> +		: "memory"
> +	);
> +}
> +
> +int main(void)
> +{
> +	report_prefix_push("pgmint-loop");
> +
> +	lowcore.pgm_new_psw.addr = (uint64_t) pgm_int_handler;
> +	/* bit 12 set is invalid */
> +	lowcore.pgm_new_psw.mask = extract_psw_mask() | BIT(63 - 12);
> +	mb();
> +
> +	/* cause a pgm int */
> +	*((int *)-4) = 0x42;
> +	mb();
> +
> +	report_fail("survived pgmint loop");
> +
> +	report_prefix_pop();
> +	return report_summary();
> +}
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index 7d408f2d5310..c3073bfc4363 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -188,3 +188,7 @@ groups = migration
>   [extint-loop]
>   file = extint-loop.elf
>   groups = panic
> +
> +[pgmint-loop]
> +file = pgmint-loop.elf
> +groups = panic