| Message ID | 20170721200010.29010-4-andre.przywara@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Andre, On 21/07/17 20:59, Andre Przywara wrote: > Currently there is a gic_raise_inflight_irq(), which serves the very > special purpose of handling a newly injected interrupt while an older > one is still handled. This has only one user, in vgic_vcpu_inject_irq(). > > Now with the introduction of the pending_irq lock this will later on > result in a nasty deadlock, which can only be solved properly by > actually embedding the function into the caller (and dropping the lock > later in-between). > > This has the admittedly hideous consequence of needing to export > gic_update_one_lr(), but this will go away in a later stage of a rework. > In this respect this patch is more a temporary kludge. > > Signed-off-by: Andre Przywara <andre.przywara@arm.com> > --- > xen/arch/arm/gic.c | 30 +----------------------------- > xen/arch/arm/vgic.c | 11 ++++++++++- > xen/include/asm-arm/gic.h | 2 +- > 3 files changed, 12 insertions(+), 31 deletions(-) > > diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c > index 2c99d71..5bd66a2 100644 > --- a/xen/arch/arm/gic.c > +++ b/xen/arch/arm/gic.c > @@ -44,8 +44,6 @@ static DEFINE_PER_CPU(uint64_t, lr_mask); > > #undef GIC_DEBUG > > -static void gic_update_one_lr(struct vcpu *v, int i); > - > static const struct gic_hw_operations *gic_hw_ops; > > void register_gic_ops(const struct gic_hw_operations *ops) > @@ -416,32 +414,6 @@ void gic_remove_irq_from_queues(struct vcpu *v, struct pending_irq *p) > gic_remove_from_lr_pending(v, p); > } > > -void gic_raise_inflight_irq(struct vcpu *v, unsigned int virtual_irq) > -{ > - struct pending_irq *n = irq_to_pending(v, virtual_irq); > - > - /* If an LPI has been removed meanwhile, there is nothing left to raise. */ > - if ( unlikely(!n) ) > - return; > - > - ASSERT(spin_is_locked(&v->arch.vgic.lock)); > - > - /* Don't try to update the LR if the interrupt is disabled */ > - if ( !test_bit(GIC_IRQ_GUEST_ENABLED, &n->status) ) > - return; > - > - if ( list_empty(&n->lr_queue) ) > - { > - if ( v == current ) > - gic_update_one_lr(v, n->lr); > - } > -#ifdef GIC_DEBUG > - else > - gdprintk(XENLOG_DEBUG, "trying to inject irq=%u into d%dv%d, when it is still lr_pending\n", > - virtual_irq, v->domain->domain_id, v->vcpu_id); > -#endif > -} > - > /* > * Find an unused LR to insert an IRQ into, starting with the LR given > * by @lr. If this new interrupt is a PRISTINE LPI, scan the other LRs to > @@ -503,7 +475,7 @@ void gic_raise_guest_irq(struct vcpu *v, unsigned int virtual_irq, > gic_add_to_lr_pending(v, p); > } > > -static void gic_update_one_lr(struct vcpu *v, int i) > +void gic_update_one_lr(struct vcpu *v, int i) > { > struct pending_irq *p; > int irq; > diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c > index 38dacd3..7b122cd 100644 > --- a/xen/arch/arm/vgic.c > +++ b/xen/arch/arm/vgic.c > @@ -536,7 +536,16 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int virq) > > if ( !list_empty(&n->inflight) ) > { > - gic_raise_inflight_irq(v, virq); > + bool update = test_bit(GIC_IRQ_GUEST_ENABLED, &n->status) && > + list_empty(&n->lr_queue) && (v == current); > + > + if ( update ) > + gic_update_one_lr(v, n->lr); > +#ifdef GIC_DEBUG > + else > + gdprintk(XENLOG_DEBUG, "trying to inject irq=%u into d%dv%d, when it is still lr_pending\n", > + n->irq, v->domain->domain_id, v->vcpu_id); The previous code was only printing this message when the pending_irq is queued. Now you will print any time you don't update the LR. > +#endif > goto out; > } > > diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h > index 6203dc5..cf8b8fb 100644 > --- a/xen/include/asm-arm/gic.h > +++ b/xen/include/asm-arm/gic.h > @@ -237,12 +237,12 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned int virq, > > extern void gic_inject(void); > extern void gic_clear_pending_irqs(struct vcpu *v); > +extern void gic_update_one_lr(struct vcpu *v, int lr); > extern int gic_events_need_delivery(void); > > extern void init_maintenance_interrupt(void); > extern void gic_raise_guest_irq(struct vcpu *v, unsigned int irq, > unsigned int priority); > -extern void gic_raise_inflight_irq(struct vcpu *v, unsigned int virtual_irq); > extern void gic_remove_from_lr_pending(struct vcpu *v, struct pending_irq *p); > extern void gic_remove_irq_from_queues(struct vcpu *v, struct pending_irq *p); > > Cheers,
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 2c99d71..5bd66a2 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -44,8 +44,6 @@ static DEFINE_PER_CPU(uint64_t, lr_mask); #undef GIC_DEBUG -static void gic_update_one_lr(struct vcpu *v, int i); - static const struct gic_hw_operations *gic_hw_ops; void register_gic_ops(const struct gic_hw_operations *ops) @@ -416,32 +414,6 @@ void gic_remove_irq_from_queues(struct vcpu *v, struct pending_irq *p) gic_remove_from_lr_pending(v, p); } -void gic_raise_inflight_irq(struct vcpu *v, unsigned int virtual_irq) -{ - struct pending_irq *n = irq_to_pending(v, virtual_irq); - - /* If an LPI has been removed meanwhile, there is nothing left to raise. */ - if ( unlikely(!n) ) - return; - - ASSERT(spin_is_locked(&v->arch.vgic.lock)); - - /* Don't try to update the LR if the interrupt is disabled */ - if ( !test_bit(GIC_IRQ_GUEST_ENABLED, &n->status) ) - return; - - if ( list_empty(&n->lr_queue) ) - { - if ( v == current ) - gic_update_one_lr(v, n->lr); - } -#ifdef GIC_DEBUG - else - gdprintk(XENLOG_DEBUG, "trying to inject irq=%u into d%dv%d, when it is still lr_pending\n", - virtual_irq, v->domain->domain_id, v->vcpu_id); -#endif -} - /* * Find an unused LR to insert an IRQ into, starting with the LR given * by @lr. If this new interrupt is a PRISTINE LPI, scan the other LRs to @@ -503,7 +475,7 @@ void gic_raise_guest_irq(struct vcpu *v, unsigned int virtual_irq, gic_add_to_lr_pending(v, p); } -static void gic_update_one_lr(struct vcpu *v, int i) +void gic_update_one_lr(struct vcpu *v, int i) { struct pending_irq *p; int irq; diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c index 38dacd3..7b122cd 100644 --- a/xen/arch/arm/vgic.c +++ b/xen/arch/arm/vgic.c @@ -536,7 +536,16 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int virq) if ( !list_empty(&n->inflight) ) { - gic_raise_inflight_irq(v, virq); + bool update = test_bit(GIC_IRQ_GUEST_ENABLED, &n->status) && + list_empty(&n->lr_queue) && (v == current); + + if ( update ) + gic_update_one_lr(v, n->lr); +#ifdef GIC_DEBUG + else + gdprintk(XENLOG_DEBUG, "trying to inject irq=%u into d%dv%d, when it is still lr_pending\n", + n->irq, v->domain->domain_id, v->vcpu_id); +#endif goto out; } diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h index 6203dc5..cf8b8fb 100644 --- a/xen/include/asm-arm/gic.h +++ b/xen/include/asm-arm/gic.h @@ -237,12 +237,12 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned int virq, extern void gic_inject(void); extern void gic_clear_pending_irqs(struct vcpu *v); +extern void gic_update_one_lr(struct vcpu *v, int lr); extern int gic_events_need_delivery(void); extern void init_maintenance_interrupt(void); extern void gic_raise_guest_irq(struct vcpu *v, unsigned int irq, unsigned int priority); -extern void gic_raise_inflight_irq(struct vcpu *v, unsigned int virtual_irq); extern void gic_remove_from_lr_pending(struct vcpu *v, struct pending_irq *p); extern void gic_remove_irq_from_queues(struct vcpu *v, struct pending_irq *p);
Currently there is a gic_raise_inflight_irq(), which serves the very special purpose of handling a newly injected interrupt while an older one is still handled. This has only one user, in vgic_vcpu_inject_irq(). Now with the introduction of the pending_irq lock this will later on result in a nasty deadlock, which can only be solved properly by actually embedding the function into the caller (and dropping the lock later in-between). This has the admittedly hideous consequence of needing to export gic_update_one_lr(), but this will go away in a later stage of a rework. In this respect this patch is more a temporary kludge. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- xen/arch/arm/gic.c | 30 +----------------------------- xen/arch/arm/vgic.c | 11 ++++++++++- xen/include/asm-arm/gic.h | 2 +- 3 files changed, 12 insertions(+), 31 deletions(-)