Re: [kvm-unit-tests PATCH v2 4/4] s390x: Test effect of storage keys on diag 308

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Tue, 17 May 2022 13:56:07 +0200
Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:

> Test that key-controlled protection does not apply to diag 308.
> 
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
>  s390x/skey.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/s390x/skey.c b/s390x/skey.c
> index 60ae8158..c2d28ffd 100644
> --- a/s390x/skey.c
> +++ b/s390x/skey.c
> @@ -285,6 +285,31 @@ static void test_store_cpu_address(void)
>  	report_prefix_pop();
>  }
>  
> +static void test_diag_308(void)
> +{
> +	uint16_t response;
> +	uint32_t (*ipib)[1024] = (void *)pagebuf;

why not just uint32_t *ipib = (void *)pagebuf; ?

> +
> +	report_prefix_push("DIAG 308");
> +	(*ipib)[0] = 0; /* Invalid length */

then you can simply do:

ipib[0] = 0;

> +	set_storage_key(ipib, 0x28, 0);
> +	/* key-controlled protection does not apply */
> +	asm volatile (
> +		"lr	%%r2,%[ipib]\n\t"
> +		"spka	0x10\n\t"
> +		"diag	%%r2,%[code],0x308\n\t"
> +		"spka	0\n\t"
> +		"lr	%[response],%%r3\n"
> +		: [response] "=d" (response)
> +		: [ipib] "d" (ipib),
> +		  [code] "d" (5)
> +		: "%r2", "%r3"
> +	);
> +	report(response == 0x402, "no exception on fetch, response: invalid IPIB");
> +	set_storage_key(ipib, 0x00, 0);
> +	report_prefix_pop();
> +}
> +
>  /*
>   * Perform CHANNEL SUBSYSTEM CALL (CHSC)  instruction while temporarily executing
>   * with access key 1.
> @@ -714,6 +739,7 @@ int main(void)
>  	test_chg();
>  	test_test_protection();
>  	test_store_cpu_address();
> +	test_diag_308();
>  	test_channel_subsystem_call();
>  
>  	setup_vm();