Re: [Qemu-devel] [PATCH 2/3] s390/css: Fix subchannel detection

[Andreas Färber]

Am 22.02.2013 20:01, schrieb Jens Freimann:
> From: Christian Borntraeger <address@hidden>
> 
> We have to consider the m bit to find the real channel subsystem when
> determining the last subchannel.
> 
> If we fail to take this into account, removal of a subchannel in
> the middle of a big list of devices will stop device detection after
> a reboot.
> 
> Signed-off-by: Christian Borntraeger <address@hidden>
> Signed-off-by: Jens Freimann <address@hidden>
> Reviewed-by: Cornelia Huck <address@hidden>
> ---
>  hw/s390x/css.c        | 11 +++++++----
>  target-s390x/cpu.h    |  2 +-
>  target-s390x/ioinst.c |  2 +-
>  3 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index 3244201..8240e48 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -988,15 +988,18 @@ int css_do_rchp(uint8_t cssid, uint8_t chpid)
>      return 0;
>  }
>  
> -bool css_schid_final(uint8_t cssid, uint8_t ssid, uint16_t schid)
> +bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid)
>  {
>      SubchSet *set;
> +    uint8_t real_cssid;
>  
> -    if (cssid > MAX_CSSID || ssid > MAX_SSID || !channel_subsys->css[cssid] 
> ||
> -        !channel_subsys->css[cssid]->sch_set[ssid]) {
> +    real_cssid = (!m && (cssid == 0)) ? channel_subsys->default_cssid : 
> cssid;

If m is a single bit and only used as boolean here, any reason not to
make the argument a bool?

Cheers,
Andreas

> +    if (real_cssid > MAX_CSSID || ssid > MAX_SSID ||
> +        !channel_subsys->css[real_cssid] ||
> +        !channel_subsys->css[real_cssid]->sch_set[ssid]) {
>          return true;
>      }
> -    set = channel_subsys->css[cssid]->sch_set[ssid];
> +    set = channel_subsys->css[real_cssid]->sch_set[ssid];
>      return schid > find_last_bit(set->schids_used,
>                                   (MAX_SCHID + 1) / sizeof(unsigned long));
>  }
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index 01e59b9..670603a 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -405,7 +405,7 @@ SubchDev *css_find_subch(uint8_t m, uint8_t cssid, 
> uint8_t ssid,
>  bool css_subch_visible(SubchDev *sch);
>  void css_conditional_io_interrupt(SubchDev *sch);
>  int css_do_stsch(SubchDev *sch, SCHIB *schib);
> -bool css_schid_final(uint8_t cssid, uint8_t ssid, uint16_t schid);
> +bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
>  int css_do_msch(SubchDev *sch, SCHIB *schib);
>  int css_do_xsch(SubchDev *sch);
>  int css_do_csch(SubchDev *sch);
> diff --git a/target-s390x/ioinst.c b/target-s390x/ioinst.c
> index e3531f3..28c508d 100644
> --- a/target-s390x/ioinst.c
> +++ b/target-s390x/ioinst.c
> @@ -316,7 +316,7 @@ int ioinst_handle_stsch(CPUS390XState *env, uint64_t 
> reg1, uint32_t ipb)
>              cc = 3;
>          }
>      } else {
> -        if (css_schid_final(cssid, ssid, schid)) {
> +        if (css_schid_final(m, cssid, ssid, schid)) {
>              cc = 3; /* No more subchannels in this css/ss */
>          } else {
>              /* Store an empty schib. */
> 


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