kvm: Conditionally register IRQ bypass consumer

If we don't support a mechanism for bypassing IRQs, don't register as
a consumer.  This eliminates meaningless dev_info()s when the connect
fails between producer and consumer, such as on AMD systems where
kvm_x86_ops->update_pi_irte is not implemented

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 57a62d1..6c774cd 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8358,19 +8358,21 @@ bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 }
 EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);
 
+bool kvm_arch_has_irq_bypass(void)
+{
+       return kvm_x86_ops->update_pi_irte != NULL;
+}
+
 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
                                      struct irq_bypass_producer *prod)
 {
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);
 
-       if (kvm_x86_ops->update_pi_irte) {
-               irqfd->producer = prod;
-               return kvm_x86_ops->update_pi_irte(irqfd->kvm,
-                               prod->irq, irqfd->gsi, 1);
-       }
+       irqfd->producer = prod;
 
-       return -EINVAL;
+       return kvm_x86_ops->update_pi_irte(irqfd->kvm,
+                                          prod->irq, irqfd->gsi, 1);
 }
 
 void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
@@ -8380,11 +8382,6 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);
 
-       if (!kvm_x86_ops->update_pi_irte) {
-               WARN_ON(irqfd->producer != NULL);
-               return;
-       }
-
        WARN_ON(irqfd->producer != prod);
        irqfd->producer = NULL;
 

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 352889d..92a0229 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1185,6 +1185,7 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
 #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
 
 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+bool kvm_arch_has_irq_bypass(void);
 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *,
                           struct irq_bypass_producer *);
 void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *,

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 46dbc0a..e469b60 100644 (file)
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -408,15 +408,17 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
         */
        fdput(f);
 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
-       irqfd->consumer.token = (void *)irqfd->eventfd;
-       irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
-       irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
-       irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
-       irqfd->consumer.start = kvm_arch_irq_bypass_start;
-       ret = irq_bypass_register_consumer(&irqfd->consumer);
-       if (ret)
-               pr_info("irq bypass consumer (token %p) registration fails: %d\n",
+       if (kvm_arch_has_irq_bypass()) {
+               irqfd->consumer.token = (void *)irqfd->eventfd;
+               irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
+               irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
+               irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
+               irqfd->consumer.start = kvm_arch_irq_bypass_start;
+               ret = irq_bypass_register_consumer(&irqfd->consumer);
+               if (ret)
+                       pr_info("irq bypass consumer (token %p) registration fails: %d\n",
                                irqfd->consumer.token, ret);
+       }
 #endif
 
        return 0;