Re: [kvm-unit-tests PATCH v3] s390x: Add tests for execute-type instructions

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

On 2/28/23 21:44, Nina Schoetterl-Glausch wrote:
> Test the instruction address used by targets of an execute instruction.
> When the target instruction calculates a relative address, the result is
> relative to the target instruction, not the execute instruction.
> 
> Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>

Some small nits below, I can fix that up when picking.

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> ---
> 
> 
[...]
>   s390x/Makefile      |   1 +
>   s390x/ex.c          | 169 ++++++++++++++++++++++++++++++++++++++++++++
>   s390x/unittests.cfg |   3 +
>   .gitlab-ci.yml      |   1 +
>   4 files changed, 174 insertions(+)
>   create mode 100644 s390x/ex.c
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 97a61611..6cf8018b 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -39,6 +39,7 @@ tests += $(TEST_DIR)/panic-loop-extint.elf
>   tests += $(TEST_DIR)/panic-loop-pgm.elf
>   tests += $(TEST_DIR)/migration-sck.elf
>   tests += $(TEST_DIR)/exittime.elf
> +tests += $(TEST_DIR)/ex.elf
>   
>   pv-tests += $(TEST_DIR)/pv-diags.elf
>   
> diff --git a/s390x/ex.c b/s390x/ex.c
> new file mode 100644
> index 00000000..3a22e496
> --- /dev/null
> +++ b/s390x/ex.c
> @@ -0,0 +1,169 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright IBM Corp. 2023
> + *
> + * Test EXECUTE (RELATIVE LONG).
> + * These instruction execute a target instruction. The target instruction is formed

s/instruction/instructions/ ?

> + * by reading an instruction from memory and optionally modifying some of its bits.
> + * The execution of the target instruction is the same as if it was executed
> + * normally as part of the instruction sequence, except for the instruction
> + * address and the instruction-length code.
> + */
> +
> +#include <libcflat.h>
> +

[...]

> +static void test_larl(void)
> +{
> +	uint64_t target, addr;
> +
> +	report_prefix_push("LARL");
> +	asm volatile ( ".pushsection .rodata\n"
> +		"0:	larl	%[addr],0\n"
> +		"	.popsection\n"
> +
> +		"	larl	%[target],0b\n"
> +		"	exrl	0,0b\n"
> +		: [target] "=d" (target),
> +		  [addr] "=d" (addr)
> +	);
> +
> +	report(target == addr, "address calculated relative to LARL");
> +	report_prefix_pop();
> +}
> +
> +/* LOAD LOGICAL RELATIVE LONG.
> + * If it is the target of an execute-type instruction, the address is relative
> + * to the LLGFRL.
> + */

This is the only instruction where there's no comment about the execute 
behavior but it would only make sense that it follows the same address 
generation rules.

> +static void test_llgfrl(void)
> +{
> +	uint64_t target, value;
> +
> +	report_prefix_push("LLGFRL");
> +	asm volatile ( ".pushsection .rodata\n"
> +		"	.balign	4\n"
> +		"0:	llgfrl	%[value],0\n"
> +		"	.popsection\n"
> +
> +		"	llgfrl	%[target],0b\n"
> +		"	exrl	0,0b\n"
> +		: [target] "=d" (target),
> +		  [value] "=d" (value)
> +	);
> +
> +	report(target == value, "loaded correct value");
> +	report_prefix_pop();
> +}
> +
> +/*
> + * COMPARE RELATIVE LONG
> + * If it is the target of an execute-type instruction, the address is relative
> + * to the CRL.
> + */
> +static void test_crl(void)
> +{
> +	uint32_t program_mask, cc, crl_word;
> +
> +	report_prefix_push("CRL");
> +	asm volatile ( ".pushsection .rodata\n"
> +		"	.balign	4\n" //operand of crl must be word aligned

Just put it on a new line so we don't mix commenting stiles.
Inline assembly is already hardly readable anyway.

> +		"0:	crl	%[crl_word],0\n"
> +		"	.popsection\n"
> +
> +		"	lrl	%[crl_word],0b\n"
> +		//align (pad with nop), in case the wrong bad operand is used
> +		"	.balignw 4,0x0707\n"
> +		"	exrl	0,0b\n"
> +		"	ipm	%[program_mask]\n"
> +		: [program_mask] "=d" (program_mask),
> +		  [crl_word] "=d" (crl_word)
> +		:: "cc"
> +	);
> +
> +	cc = program_mask >> 28;
> +	report(!cc, "operand compared to is relative to CRL");
> +	report_prefix_pop();
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	report_prefix_push("ex");
> +	test_basr();
> +	test_bras();
> +	test_larl();
> +	test_llgfrl();
> +	test_crl();
> +	report_prefix_pop();
> +
> +	return report_summary();
> +}
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index d97eb5e9..b61faf07 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -215,3 +215,6 @@ file = migration-skey.elf
>   smp = 2
>   groups = migration
>   extra_params = -append '--parallel'
> +
> +[execute]
> +file = ex.elf
> diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
> index ad7949c9..a999f64a 100644
> --- a/.gitlab-ci.yml
> +++ b/.gitlab-ci.yml
> @@ -275,6 +275,7 @@ s390x-kvm:
>     - ACCEL=kvm ./run_tests.sh
>         selftest-setup intercept emulator sieve sthyi diag10 diag308 pfmf
>         cmm vector gs iep cpumodel diag288 stsi sclp-1g sclp-3g css skrf sie
> +      execute
>         | tee results.txt
>     - grep -q PASS results.txt && ! grep -q FAIL results.txt
>    only:
> 
> base-commit: e3c5c3ef2524c58023073c0fadde2e8ae3c04ec6