Re: [Xen-devel] [PATCH 4/5] RTC: Add RTC update-ended interrupt support

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2012-03-05 at 03:25 -0500, Zhang, Yang Z wrote:
> Use a timer to emulate update cycle. When update cycle ended and UIE
> is set, raise an interrupt. The timer runs only when AF is cleared. 

Isn't this putting back a load of stuff which you removed in your first
patch?

> 
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> 
> diff -r edc35b026509 -r 3215fd33b9b1 xen/arch/x86/hvm/rtc.c
> --- a/xen/arch/x86/hvm/rtc.c    Mon Mar 05 14:39:41 2012 +0800
> +++ b/xen/arch/x86/hvm/rtc.c    Mon Mar 05 14:49:04 2012 +0800
> @@ -29,6 +29,7 @@
>  #include <asm/current.h>
> 
>  #define USEC_PER_SEC    1000000UL
> +#define NS_PER_USEC     1000UL
> 
>  #define domain_vrtc(x) (&(x)->arch.hvm_domain.pl_time.vrtc)
>  #define vcpu_vrtc(x)   (domain_vrtc((x)->domain))
> @@ -74,6 +75,84 @@ static void rtc_timer_update(RTCState *s
>      }
>  }
> 
> +/* handle update-ended timer */
> +static void check_update_timer(RTCState *s)
> +{
> +    uint64_t next_update_time, expire_time;
> +    uint64_t guest_usec;
> +    struct domain *d = vrtc_domain(s);
> +    stop_timer(&s->update_timer);
> +    stop_timer(&s->update_timer2);
> +
> +    ASSERT(spin_is_locked(&s->lock));
> +
> +    if (!(s->hw.cmos_data[RTC_REG_C] & RTC_UF) &&
> +            !(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
> +    {
> +        s->use_timer = 1;
> +        guest_usec = get_localtime_us(d) % USEC_PER_SEC;
> +        if (guest_usec >= (USEC_PER_SEC - 244))
> +        {
> +            /* RTC is in update cycle when enabling UIE */
> +            s->hw.cmos_data[RTC_REG_A] |= RTC_UIP;
> +            next_update_time = (USEC_PER_SEC - guest_usec) * NS_PER_USEC;
> +            expire_time = NOW() + next_update_time;
> +            /* release lock before set timer */
> +            spin_unlock(&s->lock);
> +            set_timer(&s->update_timer2, expire_time);
> +            /* fetch lock again */
> +            spin_lock(&s->lock);
> +        }
> +        else
> +        {
> +            next_update_time = (USEC_PER_SEC - guest_usec - 244) * 
> NS_PER_USEC;
> +            expire_time = NOW() + next_update_time;
> +            s->next_update_time = expire_time;
> +            /* release lock before set timer */
> +            spin_unlock(&s->lock);
> +            set_timer(&s->update_timer, expire_time);
> +            /* fetch lock again */
> +            spin_lock(&s->lock);
> +        }
> +    }
> +    else
> +        s->use_timer = 0;
> +}
> +
> +static void rtc_update_timer(void *opaque)
> +{
> +    RTCState *s = opaque;
> +
> +    spin_lock(&s->lock);
> +    if (!(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
> +    {
> +        s->hw.cmos_data[RTC_REG_A] |= RTC_UIP;
> +        set_timer(&s->update_timer2, s->next_update_time + 244000UL);
> +    }
> +    spin_unlock(&s->lock);
> +}
> +
> +static void rtc_update_timer2(void *opaque)
> +{
> +    RTCState *s = opaque;
> +    struct domain *d = vrtc_domain(s);
> +
> +    spin_lock(&s->lock);
> +    if (!(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
> +    {
> +        s->hw.cmos_data[RTC_REG_C] |= RTC_UF;
> +        s->hw.cmos_data[RTC_REG_A] &= ~RTC_UIP;
> +        if ((s->hw.cmos_data[RTC_REG_B] & RTC_UIE))
> +        {
> +            s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
> +            hvm_isa_irq_deassert(d, RTC_IRQ);
> +            hvm_isa_irq_assert(d, RTC_IRQ);
> +        }
> +        check_update_timer(s);
> +    }
> +    spin_unlock(&s->lock);
> +}
> +
>  static void rtc_set_time(RTCState *s);
> 
>  static int rtc_ioport_write(void *opaque, uint32_t addr, uint32_t data)
> @@ -140,8 +219,17 @@ static int rtc_ioport_write(void *opaque
>              if ( s->hw.cmos_data[RTC_REG_B] & RTC_SET )
>                  rtc_set_time(s);
>          }
> +        /* if the interrupt is already set when the interrupt become
> +         * enabled, raise an interrupt immediately*/
> +        if ((data & RTC_UIE) && !(s->hw.cmos_data[RTC_REG_B] & RTC_UIE))
> +            if (s->hw.cmos_data[RTC_REG_C] & RTC_UF)
> +            {
> +                hvm_isa_irq_deassert(d, RTC_IRQ);
> +                hvm_isa_irq_assert(d, RTC_IRQ);
> +            }
>          s->hw.cmos_data[RTC_REG_B] = data;
>          rtc_timer_update(s);
> +        check_update_timer(s);
>          break;
>      case RTC_REG_C:
>      case RTC_REG_D:
> @@ -286,13 +374,14 @@ static uint32_t rtc_ioport_read(RTCState
>          break;
>      case RTC_REG_A:
>          ret = s->hw.cmos_data[s->hw.cmos_index];
> -        if (update_in_progress(s))
> +        if ((s->use_timer == 0) && update_in_progress(s))
>              ret |= RTC_UIP;
>          break;
>      case RTC_REG_C:
>          ret = s->hw.cmos_data[s->hw.cmos_index];
>          hvm_isa_irq_deassert(vrtc_domain(s), RTC_IRQ);
>          s->hw.cmos_data[RTC_REG_C] = 0x00;
> +        check_update_timer(s);
>          break;
>      default:
>          ret = s->hw.cmos_data[s->hw.cmos_index];
> @@ -331,9 +420,12 @@ static int handle_rtc_io(
> 
>  void rtc_migrate_timers(struct vcpu *v)
>  {
> +    RTCState *s = vcpu_vrtc(v);
> +
>      if ( v->vcpu_id == 0 )
>      {
> -        ;
> +        migrate_timer(&s->update_timer, v->processor);;
> +        migrate_timer(&s->update_timer2, v->processor);;
>      }
>  }
> 
> @@ -369,6 +461,7 @@ static int rtc_load(struct domain *d, hv
> 
>      /* Reset the periodic interrupt timer based on the registers */
>      rtc_timer_update(s);
> +    check_update_timer(s);
> 
>      spin_unlock(&s->lock);
> 
> @@ -391,10 +484,14 @@ void rtc_init(struct domain *d)
> 
>      spin_lock_init(&s->lock);
> 
> +    init_timer(&s->update_timer, rtc_update_timer, s, smp_processor_id());
> +    init_timer(&s->update_timer2, rtc_update_timer2, s, smp_processor_id());
> +
>      register_portio_handler(d, RTC_PORT(0), 2, handle_rtc_io);
> 
>      rtc_reset(d);
> 
> +
>      spin_lock(&s->lock);
> 
>      s->hw.cmos_data[RTC_REG_A] = RTC_REF_CLCK_32KHZ | 6; /* ~1kHz */
> @@ -406,6 +503,7 @@ void rtc_init(struct domain *d)
> 
>      rtc_copy_date(s);
> 
> +    check_update_timer(s);
>      spin_unlock(&s->lock);
>  }
> 
> @@ -416,6 +514,8 @@ void rtc_deinit(struct domain *d)
>      spin_barrier(&s->lock);
> 
>      destroy_periodic_time(&s->pt);
> +    kill_timer(&s->update_timer);
> +    kill_timer(&s->update_timer2);
>  }
> 
>  void rtc_update_clock(struct domain *d)
> diff -r edc35b026509 -r 3215fd33b9b1 xen/include/asm-x86/hvm/vpt.h
> --- a/xen/include/asm-x86/hvm/vpt.h     Mon Mar 05 14:39:41 2012 +0800
> +++ b/xen/include/asm-x86/hvm/vpt.h     Mon Mar 05 14:49:04 2012 +0800
> @@ -107,6 +107,11 @@ typedef struct RTCState {
>      /* second update */
>      int64_t next_second_time;
>      struct periodic_time pt;
> +    /* update-ended timer */
> +    struct timer update_timer;
> +    struct timer update_timer2;
> +    uint64_t next_update_time;
> +    uint32_t use_timer;
>      spinlock_t lock;
>  } RTCState;
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel