Re: [kvm-unit-tests PATCH v12 9/9] s390x: css: ssch/tsch with sense and interrupt

Thomas Huth
2020-07-14T11:38:21Z

On 14/07/2020 13.15, Pierre Morel wrote:
> After a channel is enabled we start a SENSE_ID command using
> the SSCH instruction to recognize the control unit and device.
>
> This tests the success of SSCH, the I/O interruption and the TSCH
> instructions.
>
> The SENSE_ID command response is tested to report 0xff inside
> its reserved field and to report the same control unit type
> as the cu_type kernel argument.
>
> Without the cu_type kernel argument, the test expects a device
> with a default control unit type of 0x3832, a.k.a virtio-net-ccw.
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
[...]
> @@ -102,6 +113,19 @@ struct irb {
> uint32_t emw[8];
> } __attribute__ ((aligned(4)));
>
> +#define CCW_CMD_SENSE_ID 0xe4
> +#define CSS_SENSEID_COMMON_LEN 8
> +struct senseid {
> + /* common part */
> + uint8_t reserved; /* always 0x'FF' */
> + uint16_t cu_type; /* control unit type */
> + uint8_t cu_model; /* control unit model */
> + uint16_t dev_type; /* device type */
> + uint8_t dev_model; /* device model */
> + uint8_t unused; /* padding byte */
> + uint8_t padding[256 - 10]; /* Extra padding for CCW */
> +} __attribute__ ((aligned(4))) __attribute__ ((packed));

Is that padding[256 - 10] right? If I count right, there are only 8
bytes before the padding field, so "10" sounds wrong here?

[...]
> diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
> index e47a945..274c293 100644
> --- a/lib/s390x/css_lib.c
> +++ b/lib/s390x/css_lib.c
[...]
> +/*
> + * css_residual_count
> + * Return the residual count, if it is valid.
> + *
> + * Return value:
> + * Success: the residual count
> + * Not meaningful: -1 (-1 can not be a valid count)
> + */
> +int css_residual_count(unsigned int schid)
> +{
> +
> + if (!(irb.scsw.ctrl & (SCSW_SC_PENDING | SCSW_SC_PRIMARY)))
> + goto invalid;
> +
> + if (irb.scsw.dev_stat)
> + if (irb.scsw.sch_stat & ~(SCSW_SCHS_PCI | SCSW_SCHS_IL))
> + goto invalid;
> +
> + return irb.scsw.count;
> +
> +invalid:
> + return -1;
> +}

Cosmetical nit: Unless you want to add something between "invalid:" and
"return -1" later, I'd rather replace "goto invalid" with "return -1"
and get rid of the "invalid" label here.

Thomas