[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v7 10/12] xen/arm: don't protect GICH and lr_queue accesses with gic.lock
GICH is banked, protect accesses by disabling interrupts. Protect lr_queue accesses with the vgic.lock only. gic.lock only protects accesses to GICD now. Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> --- Changes in v5: - gic_remove_from_queues need to be protected with a vgic lock; - introduce ASSERTs to check the vgic is locked and interrupts are disabled. Changes in v4: - improved in code comments. --- xen/arch/arm/gic.c | 35 ++++++++++++++++------------------- xen/arch/arm/vgic.c | 9 +++++++-- xen/include/asm-arm/domain.h | 5 ++++- 3 files changed, 27 insertions(+), 22 deletions(-) diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 13ce703..e6e6f1a 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -119,6 +119,7 @@ void gic_save_state(struct vcpu *v) void gic_restore_state(struct vcpu *v) { int i; + ASSERT(!local_irq_is_enabled()); if ( is_idle_vcpu(v) ) return; @@ -630,6 +631,7 @@ static inline void gic_set_lr(int lr, struct pending_irq *p, { uint32_t lr_reg; + ASSERT(!local_irq_is_enabled()); BUG_ON(lr >= nr_lrs); BUG_ON(lr < 0); BUG_ON(state & ~(GICH_LR_STATE_MASK<<GICH_LR_STATE_SHIFT)); @@ -650,6 +652,8 @@ static inline void gic_add_to_lr_pending(struct vcpu *v, struct pending_irq *n) { struct pending_irq *iter; + ASSERT(spin_is_locked(&v->arch.vgic.lock)); + if ( !list_empty(&n->lr_queue) ) return; @@ -669,19 +673,20 @@ void gic_remove_from_queues(struct vcpu *v, unsigned int virtual_irq) struct pending_irq *p = irq_to_pending(v, virtual_irq); unsigned long flags; - spin_lock_irqsave(&gic.lock, flags); + spin_lock_irqsave(&v->arch.vgic.lock, flags); if ( !list_empty(&p->lr_queue) ) list_del_init(&p->lr_queue); - spin_unlock_irqrestore(&gic.lock, flags); + spin_unlock_irqrestore(&v->arch.vgic.lock, flags); } void gic_raise_guest_irq(struct vcpu *v, unsigned int virtual_irq, unsigned int priority) { int i; - unsigned long flags; struct pending_irq *n = irq_to_pending(v, virtual_irq); + ASSERT(spin_is_locked(&v->arch.vgic.lock)); + if ( test_bit(GIC_IRQ_GUEST_VISIBLE, &n->status)) { if ( v == current ) @@ -689,23 +694,17 @@ void gic_raise_guest_irq(struct vcpu *v, unsigned int virtual_irq, return; } - spin_lock_irqsave(&gic.lock, flags); - if ( v == current && list_empty(&v->arch.vgic.lr_pending) ) { i = find_first_zero_bit(&this_cpu(lr_mask), nr_lrs); if (i < nr_lrs) { set_bit(i, &this_cpu(lr_mask)); gic_set_lr(i, irq_to_pending(v, virtual_irq), GICH_LR_PENDING); - goto out; + return; } } gic_add_to_lr_pending(v, irq_to_pending(v, virtual_irq)); - -out: - spin_unlock_irqrestore(&gic.lock, flags); - return; } static void gic_update_one_lr(struct vcpu *v, int i) @@ -715,6 +714,7 @@ static void gic_update_one_lr(struct vcpu *v, int i) int irq; ASSERT(spin_is_locked(&v->arch.vgic.lock)); + ASSERT(!local_irq_is_enabled()); lr = GICH[GICH_LR + i]; irq = (lr >> GICH_LR_VIRTUAL_SHIFT) & GICH_LR_VIRTUAL_MASK; @@ -729,8 +729,6 @@ static void gic_update_one_lr(struct vcpu *v, int i) } else if ( lr & GICH_LR_PENDING ) { clear_bit(GIC_IRQ_GUEST_QUEUED, &p->status); } else { - spin_lock(&gic.lock); - GICH[GICH_LR + i] = 0; clear_bit(i, &this_cpu(lr_mask)); @@ -744,8 +742,6 @@ static void gic_update_one_lr(struct vcpu *v, int i) gic_raise_guest_irq(v, irq, p->priority); } else list_del_init(&p->inflight); - - spin_unlock(&gic.lock); } } @@ -776,11 +772,11 @@ static void gic_restore_pending_irqs(struct vcpu *v) i = find_first_zero_bit(&this_cpu(lr_mask), nr_lrs); if ( i >= nr_lrs ) return; - spin_lock_irqsave(&gic.lock, flags); + spin_lock_irqsave(&v->arch.vgic.lock, flags); gic_set_lr(i, p, GICH_LR_PENDING); list_del_init(&p->lr_queue); set_bit(i, &this_cpu(lr_mask)); - spin_unlock_irqrestore(&gic.lock, flags); + spin_unlock_irqrestore(&v->arch.vgic.lock, flags); } } @@ -788,13 +784,12 @@ static void gic_restore_pending_irqs(struct vcpu *v) void gic_clear_pending_irqs(struct vcpu *v) { struct pending_irq *p, *t; - unsigned long flags; - spin_lock_irqsave(&gic.lock, flags); + ASSERT(spin_is_locked(&v->arch.vgic.lock)); + v->arch.lr_mask = 0; list_for_each_entry_safe ( p, t, &v->arch.vgic.lr_pending, lr_queue ) list_del_init(&p->lr_queue); - spin_unlock_irqrestore(&gic.lock, flags); } int gic_events_need_delivery(void) @@ -805,6 +800,8 @@ int gic_events_need_delivery(void) void gic_inject(void) { + ASSERT(!local_irq_is_enabled()); + gic_restore_pending_irqs(current); if ( !list_empty(¤t->arch.vgic.lr_pending) && lr_all_full() ) diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c index 435a8d7..c5e17e0 100644 --- a/xen/arch/arm/vgic.c +++ b/xen/arch/arm/vgic.c @@ -393,8 +393,13 @@ static void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n) vcpu_info(current, evtchn_upcall_pending) && list_empty(&p->inflight) ) vgic_vcpu_inject_irq(v, irq); - else if ( !list_empty(&p->inflight) && !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) ) - gic_raise_guest_irq(v, irq, p->priority); + else { + unsigned long flags; + spin_lock_irqsave(&v->arch.vgic.lock, flags); + if ( !list_empty(&p->inflight) && !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) ) + gic_raise_guest_irq(v, irq, p->priority); + spin_unlock_irqrestore(&v->arch.vgic.lock, flags); + } if ( p->desc != NULL ) p->desc->handler->enable(p->desc); i++; diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h index f96dc12..71f563f 100644 --- a/xen/include/asm-arm/domain.h +++ b/xen/include/asm-arm/domain.h @@ -68,7 +68,10 @@ struct pending_irq * vgic.inflight_irqs */ struct list_head inflight; /* lr_queue is used to append instances of pending_irq to - * gic.lr_pending */ + * lr_pending. lr_pending is a per vcpu queue, therefore lr_queue + * accesses are protected with the vgic lock. + * TODO: when implementing irq migration, taking only the current + * vgic lock is not going to be enough. */ struct list_head lr_queue; }; -- 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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