KVM: Userspace controlled irq routing
Currently KVM has a static routing from GSI numbers to interrupts (namely,
0-15 are mapped 1:1 to both PIC and IOAPIC, and 16:23 are mapped 1:1 to
the IOAPIC). This is insufficient for several reasons:
- HPET requires non 1:1 mapping for the timer interrupt
- MSIs need a new method to assign interrupt numbers and dispatch them
- ACPI APIC mode needs to be able to reassign the PCI LINK interrupts to the
ioapics
This patch implements an interrupt routing table (as a linked list, but this
can be easily changed) and a userspace interface to replace the table. The
routing table is initialized according to the current hardwired mapping.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 786a3ae..c65484b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -843,6 +843,7 @@
if (IS_ERR(kvm))
goto out;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
+ INIT_LIST_HEAD(&kvm->irq_routing);
INIT_HLIST_HEAD(&kvm->mask_notifier_list);
#endif
@@ -926,6 +927,7 @@
spin_lock(&kvm_lock);
list_del(&kvm->vm_list);
spin_unlock(&kvm_lock);
+ kvm_free_irq_routing(kvm);
kvm_io_bus_destroy(&kvm->pio_bus);
kvm_io_bus_destroy(&kvm->mmio_bus);
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
@@ -1946,6 +1948,36 @@
break;
}
#endif
+#ifdef KVM_CAP_IRQ_ROUTING
+ case KVM_SET_GSI_ROUTING: {
+ struct kvm_irq_routing routing;
+ struct kvm_irq_routing __user *urouting;
+ struct kvm_irq_routing_entry *entries;
+
+ r = -EFAULT;
+ if (copy_from_user(&routing, argp, sizeof(routing)))
+ goto out;
+ r = -EINVAL;
+ if (routing.nr >= KVM_MAX_IRQ_ROUTES)
+ goto out;
+ if (routing.flags)
+ goto out;
+ r = -ENOMEM;
+ entries = vmalloc(routing.nr * sizeof(*entries));
+ if (!entries)
+ goto out;
+ r = -EFAULT;
+ urouting = argp;
+ if (copy_from_user(entries, urouting->entries,
+ routing.nr * sizeof(*entries)))
+ goto out_free_irq_routing;
+ r = kvm_set_irq_routing(kvm, entries, routing.nr,
+ routing.flags);
+ out_free_irq_routing:
+ vfree(entries);
+ break;
+ }
+#endif
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
}
@@ -2012,6 +2044,10 @@
case KVM_CAP_USER_MEMORY:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
return 1;
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+ case KVM_CAP_IRQ_ROUTING:
+ return 1;
+#endif
default:
break;
}