Gregory Haskins wrote: > Certain GSI's support lockless injecton, but we have no way to detect > which ones at the GSI level. Knowledge of this attribute will be > useful later in the series so that we can optimize irqfd injection > paths for cases where we know the code will not sleep. Therefore, > we provide an API to query a specific GSI. > > Signed-off-by: Gregory Haskins <[email protected]> > --- > > include/linux/kvm_host.h | 2 ++ > virt/kvm/irq_comm.c | 19 +++++++++++++++++++ > 2 files changed, 21 insertions(+), 0 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index bd5a616..93393a4 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -119,6 +119,7 @@ struct kvm_memory_slot { > struct kvm_kernel_irq_routing_entry { > u32 gsi; > u32 type; > + bool lockless; > int (*set)(struct kvm_kernel_irq_routing_entry *e, > struct kvm *kvm, int irq_source_id, int level); > union { > @@ -417,6 +418,7 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic > *ioapic, > unsigned long *deliver_bitmask); > #endif > int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level); > +int kvm_irq_check_lockless(struct kvm *kvm, u32 irq); > void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin); > void kvm_register_irq_ack_notifier(struct kvm *kvm, > struct kvm_irq_ack_notifier *kian); > diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c > index 00c68d2..04f0134 100644 > --- a/virt/kvm/irq_comm.c > +++ b/virt/kvm/irq_comm.c > @@ -174,6 +174,23 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 > irq, int level) > return ret; > } > > +int kvm_irq_check_lockless(struct kvm *kvm, u32 irq) > +{ > + struct kvm_kernel_irq_routing_entry *e; > + struct kvm_irq_routing_table *irq_rt; > + struct hlist_node *n; > + int ret = -ENOENT; > + > + rcu_read_lock(); > + irq_rt = rcu_dereference(kvm->irq_routing); > + if (irq < irq_rt->nr_rt_entries) > + hlist_for_each_entry(e, n, &irq_rt->map[irq], link) > + ret = e->lockless ? 1 : 0;
Sigh... just noticed this as it hits the list. I should probably break
out of the loop here.
> + rcu_read_unlock();
> +
> + return ret;
> +}
> +
> void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
> {
> struct kvm_irq_ack_notifier *kian;
> @@ -314,6 +331,7 @@ static int setup_routing_entry(struct
> kvm_irq_routing_table *rt,
>
> e->gsi = ue->gsi;
> e->type = ue->type;
> + e->lockless = false;
> switch (ue->type) {
> case KVM_IRQ_ROUTING_IRQCHIP:
> delta = 0;
> @@ -342,6 +360,7 @@ static int setup_routing_entry(struct
> kvm_irq_routing_table *rt,
> e->msi.address_lo = ue->u.msi.address_lo;
> e->msi.address_hi = ue->u.msi.address_hi;
> e->msi.data = ue->u.msi.data;
> + e->lockless = true;
> break;
> default:
> goto out;
>
> --
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