KVM: Define a new interface kvm_intr_is_single_vcpu()
This patch defines a new interface kvm_intr_is_single_vcpu(),
which can returns whether the interrupt is for single-CPU or not.
It is used by VT-d PI, since now we only support single-CPU
interrupts, For lowest-priority interrupts, if user configures
it via /proc/irq or uses irqbalance to make it single-CPU, we
can use PI to deliver the interrupts to it. Full functionality
of lowest-priority support will be added later.
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2f4c0d0..944b38a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -755,6 +755,65 @@
return ret;
}
+bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu)
+{
+ struct kvm_apic_map *map;
+ bool ret = false;
+ struct kvm_lapic *dst = NULL;
+
+ if (irq->shorthand)
+ return false;
+
+ rcu_read_lock();
+ map = rcu_dereference(kvm->arch.apic_map);
+
+ if (!map)
+ goto out;
+
+ if (irq->dest_mode == APIC_DEST_PHYSICAL) {
+ if (irq->dest_id == 0xFF)
+ goto out;
+
+ if (irq->dest_id >= ARRAY_SIZE(map->phys_map))
+ goto out;
+
+ dst = map->phys_map[irq->dest_id];
+ if (dst && kvm_apic_present(dst->vcpu))
+ *dest_vcpu = dst->vcpu;
+ else
+ goto out;
+ } else {
+ u16 cid;
+ unsigned long bitmap = 1;
+ int i, r = 0;
+
+ if (!kvm_apic_logical_map_valid(map))
+ goto out;
+
+ apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);
+
+ if (cid >= ARRAY_SIZE(map->logical_map))
+ goto out;
+
+ for_each_set_bit(i, &bitmap, 16) {
+ dst = map->logical_map[cid][i];
+ if (++r == 2)
+ goto out;
+ }
+
+ if (dst && kvm_apic_present(dst->vcpu))
+ *dest_vcpu = dst->vcpu;
+ else
+ goto out;
+ }
+
+ ret = true;
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
/*
* Add a pending IRQ into lapic.
* Return 1 if successfully added and 0 if discarded.