[PATCH 1/3] KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic

[Paolo Bonzini <pbonzini@redhat.com>]

We do not want to do too much work in atomic context, in particular
not walking all the VCPUs of the virtual machine.  So we want
to distinguish the architecture-specific injection function for irqfd
from kvm_set_msi.  Since it's still empty, reuse the newly added
kvm_arch_set_irq and rename it to kvm_arch_set_irq_inatomic.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/irq_comm.c  | 14 ++++++++------
 include/linux/kvm_host.h |  7 +++----
 virt/kvm/eventfd.c       | 11 ++++-------
 3 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 8f4499c7ffc1..26d830c1b7af 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -124,12 +124,16 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 }
 
 
-static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e,
-			 struct kvm *kvm)
+int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
+			      struct kvm *kvm, int irq_source_id, int level,
+			      bool line_status)
 {
 	struct kvm_lapic_irq irq;
 	int r;
 
+	if (unlikely(e->type != KVM_IRQ_ROUTING_MSI))
+		return -EWOULDBLOCK;
+
 	kvm_set_msi_irq(e, &irq);
 
 	if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r, NULL))
@@ -165,10 +169,8 @@ int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 	idx = srcu_read_lock(&kvm->irq_srcu);
 	if (kvm_irq_map_gsi(kvm, entries, irq) > 0) {
 		e = &entries[0];
-		if (likely(e->type == KVM_IRQ_ROUTING_MSI))
-			ret = kvm_set_msi_inatomic(e, kvm);
-		else
-			ret = -EWOULDBLOCK;
+		ret = kvm_arch_set_irq_inatomic(e, kvm, irq_source_id,
+						irq, level);
 	}
 	srcu_read_unlock(&kvm->irq_srcu, idx);
 	return ret;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index eba9caebc9c1..42fb9e089fc9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -828,10 +828,9 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level);
 int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm,
 		int irq_source_id, int level, bool line_status);
-
-int kvm_arch_set_irq(struct kvm_kernel_irq_routing_entry *irq, struct kvm *kvm,
-		     int irq_source_id, int level, bool line_status);
-
+int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
+			       struct kvm *kvm, int irq_source_id,
+			       int level, bool line_status);
 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_notify_acked_gsi(struct kvm *kvm, int gsi);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index e29fd2640709..46dbc0a7dfc1 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -171,7 +171,7 @@ irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
 	queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
 }
 
-int __attribute__((weak)) kvm_arch_set_irq(
+int __attribute__((weak)) kvm_arch_set_irq_inatomic(
 				struct kvm_kernel_irq_routing_entry *irq,
 				struct kvm *kvm, int irq_source_id,
 				int level,
@@ -201,12 +201,9 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
 			irq = irqfd->irq_entry;
 		} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
 		/* An event has been signaled, inject an interrupt */
-		if (irq.type == KVM_IRQ_ROUTING_MSI)
-			kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
-					false);
-		else if (kvm_arch_set_irq(&irq, kvm,
-					  KVM_USERSPACE_IRQ_SOURCE_ID, 1,
-					  false) == -EWOULDBLOCK)
+		if (kvm_arch_set_irq_inatomic(&irq, kvm,
+					      KVM_USERSPACE_IRQ_SOURCE_ID, 1,
+					      false) == -EWOULDBLOCK)
 			schedule_work(&irqfd->inject);
 		srcu_read_unlock(&kvm->irq_srcu, idx);
 	}
-- 
1.8.3.1