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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 4/6] x86/HVM: properly handle RTC periodic timer even when !RTC_PIE
At 14:53 +0100 on 29 Apr (1367247238), Jan Beulich wrote:
> Since in that case the processing it pr_intr_post() won't occur, we
> need to do some additional work in pt_update_irq(). Additionally we
> must not pay attention to the respective IRQ being masked.
I don't think this is the right fix for 4.3. We should just revert to
the old system (where the vpt code raises the IRQ) rather than bodge up
the new one -- especially since the new _behaviour_ is disabled anyway.
After 4.3 branches (which is RSN, right Goerge?) we can sort out a
proper interface for all of that, and this might well be it.
Tim.
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/hvm/rtc.c
> +++ b/xen/arch/x86/hvm/rtc.c
> @@ -67,11 +67,13 @@ static void rtc_update_irq(RTCState *s)
> hvm_isa_irq_assert(vrtc_domain(s), RTC_IRQ);
> }
>
> -void rtc_periodic_interrupt(void *opaque)
> +bool_t rtc_periodic_interrupt(void *opaque)
> {
> RTCState *s = opaque;
> + bool_t ret;
>
> spin_lock(&s->lock);
> + ret = !(s->hw.cmos_data[RTC_REG_C] & RTC_IRQF);
> if ( !(s->hw.cmos_data[RTC_REG_C] & RTC_PF) )
> {
> s->hw.cmos_data[RTC_REG_C] |= RTC_PF;
> @@ -83,7 +85,11 @@ void rtc_periodic_interrupt(void *opaque
> destroy_periodic_time(&s->pt);
> s->pt_code = 0;
> }
> + if ( !(s->hw.cmos_data[RTC_REG_C] & RTC_IRQF) )
> + ret = 0;
> spin_unlock(&s->lock);
> +
> + return ret;
> }
>
> /* Enable/configure/disable the periodic timer based on the RTC_PIE and
> --- a/xen/arch/x86/hvm/vpt.c
> +++ b/xen/arch/x86/hvm/vpt.c
> @@ -216,18 +216,23 @@ static void pt_timer_fn(void *data)
> int pt_update_irq(struct vcpu *v)
> {
> struct list_head *head = &v->arch.hvm_vcpu.tm_list;
> - struct periodic_time *pt, *temp, *earliest_pt = NULL;
> - uint64_t max_lag = -1ULL;
> + struct periodic_time *pt, *temp, *earliest_pt;
> + uint64_t max_lag;
> int irq, is_lapic;
> void *pt_priv;
>
> + rescan:
> spin_lock(&v->arch.hvm_vcpu.tm_lock);
>
> + rescan_locked:
> + earliest_pt = NULL;
> + max_lag = -1ULL;
> list_for_each_entry_safe ( pt, temp, head, list )
> {
> if ( pt->pending_intr_nr )
> {
> - if ( pt_irq_masked(pt) )
> + /* RTC code takes care of disabling the timer itself. */
> + if ( (pt->irq != RTC_IRQ || !pt->priv) && pt_irq_masked(pt) )
> {
> /* suspend timer emulation */
> list_del(&pt->list);
> @@ -260,7 +265,41 @@ int pt_update_irq(struct vcpu *v)
> if ( is_lapic )
> vlapic_set_irq(vcpu_vlapic(v), irq, 0);
> else if ( irq == RTC_IRQ && pt_priv )
> - rtc_periodic_interrupt(pt_priv);
> + {
> + if ( !rtc_periodic_interrupt(pt_priv) )
> + irq = -1;
> +
> + pt_lock(earliest_pt);
> +
> + if ( irq < 0 && earliest_pt->pending_intr_nr )
> + {
> + /*
> + * RTC periodic timer runs without the corresponding interrupt
> + * being enabled - need to mimic enough of pt_intr_post() to keep
> + * things going.
> + */
> + earliest_pt->pending_intr_nr = 0;
> + earliest_pt->irq_issued = 0;
> + set_timer(&earliest_pt->timer, earliest_pt->scheduled);
> + }
> + else if ( irq >= 0 && pt_irq_masked(earliest_pt) )
> + {
> + if ( earliest_pt->on_list )
> + {
> + /* suspend timer emulation */
> + list_del(&earliest_pt->list);
> + earliest_pt->on_list = 0;
> + }
> + irq = -1;
> + }
> +
> + /* Avoid dropping the lock if we can. */
> + if ( irq < 0 && v == earliest_pt->vcpu )
> + goto rescan_locked;
> + pt_unlock(earliest_pt);
> + if ( irq < 0 )
> + goto rescan;
> + }
> else
> {
> hvm_isa_irq_deassert(v->domain, irq);
> --- a/xen/include/asm-x86/hvm/vpt.h
> +++ b/xen/include/asm-x86/hvm/vpt.h
> @@ -183,7 +183,7 @@ void rtc_migrate_timers(struct vcpu *v);
> void rtc_deinit(struct domain *d);
> void rtc_reset(struct domain *d);
> void rtc_update_clock(struct domain *d);
> -void rtc_periodic_interrupt(void *);
> +bool_t rtc_periodic_interrupt(void *);
>
> void pmtimer_init(struct vcpu *v);
> void pmtimer_deinit(struct domain *d);
>
>
>
> x86/HVM: properly handle RTC periodic timer even when !RTC_PIE
>
> Since in that case the processing it pr_intr_post() won't occur, we
> need to do some additional work in pt_update_irq(). Additionally we
> must not pay attention to the respective IRQ being masked.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/hvm/rtc.c
> +++ b/xen/arch/x86/hvm/rtc.c
> @@ -67,11 +67,13 @@ static void rtc_update_irq(RTCState *s)
> hvm_isa_irq_assert(vrtc_domain(s), RTC_IRQ);
> }
>
> -void rtc_periodic_interrupt(void *opaque)
> +bool_t rtc_periodic_interrupt(void *opaque)
> {
> RTCState *s = opaque;
> + bool_t ret;
>
> spin_lock(&s->lock);
> + ret = !(s->hw.cmos_data[RTC_REG_C] & RTC_IRQF);
> if ( !(s->hw.cmos_data[RTC_REG_C] & RTC_PF) )
> {
> s->hw.cmos_data[RTC_REG_C] |= RTC_PF;
> @@ -83,7 +85,11 @@ void rtc_periodic_interrupt(void *opaque
> destroy_periodic_time(&s->pt);
> s->pt_code = 0;
> }
> + if ( !(s->hw.cmos_data[RTC_REG_C] & RTC_IRQF) )
> + ret = 0;
> spin_unlock(&s->lock);
> +
> + return ret;
> }
>
> /* Enable/configure/disable the periodic timer based on the RTC_PIE and
> --- a/xen/arch/x86/hvm/vpt.c
> +++ b/xen/arch/x86/hvm/vpt.c
> @@ -216,18 +216,23 @@ static void pt_timer_fn(void *data)
> int pt_update_irq(struct vcpu *v)
> {
> struct list_head *head = &v->arch.hvm_vcpu.tm_list;
> - struct periodic_time *pt, *temp, *earliest_pt = NULL;
> - uint64_t max_lag = -1ULL;
> + struct periodic_time *pt, *temp, *earliest_pt;
> + uint64_t max_lag;
> int irq, is_lapic;
> void *pt_priv;
>
> + rescan:
> spin_lock(&v->arch.hvm_vcpu.tm_lock);
>
> + rescan_locked:
> + earliest_pt = NULL;
> + max_lag = -1ULL;
> list_for_each_entry_safe ( pt, temp, head, list )
> {
> if ( pt->pending_intr_nr )
> {
> - if ( pt_irq_masked(pt) )
> + /* RTC code takes care of disabling the timer itself. */
> + if ( (pt->irq != RTC_IRQ || !pt->priv) && pt_irq_masked(pt) )
> {
> /* suspend timer emulation */
> list_del(&pt->list);
> @@ -260,7 +265,41 @@ int pt_update_irq(struct vcpu *v)
> if ( is_lapic )
> vlapic_set_irq(vcpu_vlapic(v), irq, 0);
> else if ( irq == RTC_IRQ && pt_priv )
> - rtc_periodic_interrupt(pt_priv);
> + {
> + if ( !rtc_periodic_interrupt(pt_priv) )
> + irq = -1;
> +
> + pt_lock(earliest_pt);
> +
> + if ( irq < 0 && earliest_pt->pending_intr_nr )
> + {
> + /*
> + * RTC periodic timer runs without the corresponding interrupt
> + * being enabled - need to mimic enough of pt_intr_post() to keep
> + * things going.
> + */
> + earliest_pt->pending_intr_nr = 0;
> + earliest_pt->irq_issued = 0;
> + set_timer(&earliest_pt->timer, earliest_pt->scheduled);
> + }
> + else if ( irq >= 0 && pt_irq_masked(earliest_pt) )
> + {
> + if ( earliest_pt->on_list )
> + {
> + /* suspend timer emulation */
> + list_del(&earliest_pt->list);
> + earliest_pt->on_list = 0;
> + }
> + irq = -1;
> + }
> +
> + /* Avoid dropping the lock if we can. */
> + if ( irq < 0 && v == earliest_pt->vcpu )
> + goto rescan_locked;
> + pt_unlock(earliest_pt);
> + if ( irq < 0 )
> + goto rescan;
> + }
> else
> {
> hvm_isa_irq_deassert(v->domain, irq);
> --- a/xen/include/asm-x86/hvm/vpt.h
> +++ b/xen/include/asm-x86/hvm/vpt.h
> @@ -183,7 +183,7 @@ void rtc_migrate_timers(struct vcpu *v);
> void rtc_deinit(struct domain *d);
> void rtc_reset(struct domain *d);
> void rtc_update_clock(struct domain *d);
> -void rtc_periodic_interrupt(void *);
> +bool_t rtc_periodic_interrupt(void *);
>
> void pmtimer_init(struct vcpu *v);
> void pmtimer_deinit(struct domain *d);
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