Re: [kvm-unit-tests PATCH v6 07/10] s390x: css: msch, enable test

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

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On 4/24/20 12:45 PM, Pierre Morel wrote:
> A second step when testing the channel subsystem is to prepare a channel
> for use.
> This includes:
> - Get the current SubCHannel Information Block (SCHIB) using STSCH
> - Update it in memory to set the ENABLE bit
> - Tell the CSS that the SCHIB has been modified using MSCH
> - Get the SCHIB from the CSS again to verify that the subchannel is
>   enabled.
> 
> This tests the MSCH instruction to enable a channel succesfuly.

successfully

> This is NOT a routine to really enable the channel, no retry is done,
> in case of error, a report is made.

Would we expect needing retries for the pong device?

> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  s390x/css.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/s390x/css.c b/s390x/css.c
> index cc97e79..fa068bf 100644
> --- a/s390x/css.c
> +++ b/s390x/css.c
> @@ -68,11 +68,59 @@ out:
>  	       scn, scn_found, dev_found);
>  }
>  
> +static void test_enable(void)
> +{
> +	struct pmcw *pmcw = &schib.pmcw;
> +	int cc;
> +
> +	if (!test_device_sid) {
> +		report_skip("No device");
> +		return;
> +	}

If these tests are layered on top of each other and need a device to
work, we should abort or skip and exit the test if the enumeration
doesn't bring up devices

> +	/* Read the SCHIB for this subchannel */
> +	cc = stsch(test_device_sid, &schib);
> +	if (cc) {
> +		report(0, "stsch cc=%d", cc);
> +		return;
> +	}
> +
> +	/* Update the SCHIB to enable the channel */
> +	pmcw->flags |= PMCW_ENABLE;
> +
> +	/* Tell the CSS we want to modify the subchannel */
> +	cc = msch(test_device_sid, &schib);
> +	if (cc) {
> +		/*
> +		 * If the subchannel is status pending or
> +		 * if a function is in progress,
> +		 * we consider both cases as errors.
> +		 */
> +		report(0, "msch cc=%d", cc);
> +		return;
> +	}
> +
> +	/*
> +	 * Read the SCHIB again to verify the enablement
> +	 */
> +	cc = stsch(test_device_sid, &schib);
> +	if (cc) {
> +		report(0, "stsch cc=%d", cc);
> +		return;
> +	}
> +
> +	if (!(pmcw->flags & PMCW_ENABLE)) {
> +		report(0, "Enable failed. pmcw: %x", pmcw->flags);
> +		return;
> +	}
> +	report(1, "Tested");

s/Tested/Enabled/

> +}
> +
>  static struct {
>  	const char *name;
>  	void (*func)(void);
>  } tests[] = {
>  	{ "enumerate (stsch)", test_enumerate },
> +	{ "enable (msch)", test_enable },
>  	{ NULL, NULL }
>  };
>  
> 



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