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@xxxxxxxxx>
---
v9:
- Move kvm_intr_is_single_vcpu_fast() to lapic.c
- Remove incorrect WARN_ON_ONCE()
v8:
- Some optimizations in kvm_intr_is_single_vcpu().
- Expose kvm_intr_is_single_vcpu() so we can use it in vmx code.
- Add kvm_intr_is_single_vcpu_fast() as the fast path to find
the target vCPU for the single-destination interrupt
arch/x86/include/asm/kvm_host.h | 3 +++
arch/x86/kvm/irq_comm.c | 27 +++++++++++++++++++
arch/x86/kvm/lapic.c | 59 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/lapic.h | 2 ++
4 files changed, 91 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 49ec903..af11bca 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1204,4 +1204,7 @@ int __x86_set_memory_region(struct kvm *kvm,
int x86_set_memory_region(struct kvm *kvm,
const struct kvm_userspace_memory_region *mem);
+bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu);
+
#endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 9efff9e..f86a0da 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -297,6 +297,33 @@ out:
return r;
}
+bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu)
+{
+ int i, r = 0;
+ struct kvm_vcpu *vcpu;
+
+ if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
+ return true;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (!kvm_apic_present(vcpu))
+ continue;
+
+ if (!kvm_apic_match_dest(vcpu, NULL, irq->shorthand,
+ irq->dest_id, irq->dest_mode))
+ continue;
+
+ if (++r == 2)
+ return false;
+
+ *dest_vcpu = vcpu;
+ }
+
+ return r == 1;
+}
+EXPORT_SYMBOL_GPL(kvm_intr_is_single_vcpu);
+
#define IOAPIC_ROUTING_ENTRY(irq) \
{ .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
.u.irqchip = { .irqchip = KVM_IRQCHIP_IOAPIC, .pin = (irq) } }
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2a5ca97..3c8fc71 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -764,6 +764,65 @@ out:
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.
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 7195274..032fe2d 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -169,4 +169,6 @@ bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
void wait_lapic_expire(struct kvm_vcpu *vcpu);
+bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu);
#endif
--
2.1.0
--
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