Re: [PATCH 1/6] x86/HVM: fix processing of RTC REG_B writes

["Roger Pau Monné" <roger.pau@citrix.com>]

On 29/04/13 15:51, Jan Beulich wrote:
> We must store the new values before calling rtc_update_irq(), and we
> need to call rtc_timer_update() when PIE transitions from 0 to 1 (as we
> may have previously turned off the periodic timer due to the guest not
> reading REG_C, and hence may have to re-enable it in order to start
> IRQs getting delivered to the guest).
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Tested-by: Roger Pau Monné <roger.pau@citrix.com>

On FreeBSD

> 
> --- a/xen/arch/x86/hvm/rtc.c
> +++ b/xen/arch/x86/hvm/rtc.c
> @@ -468,12 +468,14 @@ static int rtc_ioport_write(void *opaque
>              if ( orig & RTC_SET )
>                  rtc_set_time(s);
>          }
> +        s->hw.cmos_data[RTC_REG_B] = data;
>          /*
>           * If the interrupt is already set when the interrupt becomes
>           * enabled, raise an interrupt immediately.
>           */
>          rtc_update_irq(s);
> -        s->hw.cmos_data[RTC_REG_B] = data;
> +        if ( (data & RTC_PIE) && !(orig & RTC_PIE) )
> +            rtc_timer_update(s);
>          if ( (data ^ orig) & RTC_SET )
>              check_update_timer(s);
>          if ( (data ^ orig) & (RTC_24H | RTC_DM_BINARY | RTC_SET) )
> 
> 
>