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/irq_comm.c b/virt/kvm/irq_comm.c
index 5162a41..a797fa5 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -24,9 +24,24 @@
#include "ioapic.h"
+static void kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int level)
+{
+#ifdef CONFIG_X86
+ kvm_pic_set_irq(pic_irqchip(kvm), e->irqchip.pin, level);
+#endif
+}
+
+static void kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int level)
+{
+ kvm_ioapic_set_irq(kvm->arch.vioapic, e->irqchip.pin, level);
+}
+
/* This should be called with the kvm->lock mutex held */
void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
{
+ struct kvm_kernel_irq_routing_entry *e;
unsigned long *irq_state = (unsigned long *)&kvm->arch.irq_states[irq];
/* Logical OR for level trig interrupt */
@@ -39,10 +54,9 @@
* IOAPIC. So set the bit in both. The guest will ignore
* writes to the unused one.
*/
- kvm_ioapic_set_irq(kvm->arch.vioapic, irq, !!(*irq_state));
-#ifdef CONFIG_X86
- kvm_pic_set_irq(pic_irqchip(kvm), irq, !!(*irq_state));
-#endif
+ list_for_each_entry(e, &kvm->irq_routing, link)
+ if (e->gsi == irq)
+ e->set(e, kvm, !!(*irq_state));
}
void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi)
@@ -123,3 +137,149 @@
kimn->func(kimn, mask);
}
+static void __kvm_free_irq_routing(struct list_head *irq_routing)
+{
+ struct kvm_kernel_irq_routing_entry *e, *n;
+
+ list_for_each_entry_safe(e, n, irq_routing, link)
+ kfree(e);
+}
+
+void kvm_free_irq_routing(struct kvm *kvm)
+{
+ __kvm_free_irq_routing(&kvm->irq_routing);
+}
+
+int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+ const struct kvm_irq_routing_entry *ue)
+{
+ int r = -EINVAL;
+ int delta;
+
+ e->gsi = ue->gsi;
+ switch (ue->type) {
+ case KVM_IRQ_ROUTING_IRQCHIP:
+ delta = 0;
+ switch (ue->u.irqchip.irqchip) {
+ case KVM_IRQCHIP_PIC_MASTER:
+ e->set = kvm_set_pic_irq;
+ break;
+ case KVM_IRQCHIP_PIC_SLAVE:
+ e->set = kvm_set_pic_irq;
+ delta = 8;
+ break;
+ case KVM_IRQCHIP_IOAPIC:
+ e->set = kvm_set_ioapic_irq;
+ break;
+ default:
+ goto out;
+ }
+ e->irqchip.irqchip = ue->u.irqchip.irqchip;
+ e->irqchip.pin = ue->u.irqchip.pin + delta;
+ break;
+ default:
+ goto out;
+ }
+ r = 0;
+out:
+ return r;
+}
+
+
+int kvm_set_irq_routing(struct kvm *kvm,
+ const struct kvm_irq_routing_entry *ue,
+ unsigned nr,
+ unsigned flags)
+{
+ struct list_head irq_list = LIST_HEAD_INIT(irq_list);
+ struct list_head tmp = LIST_HEAD_INIT(tmp);
+ struct kvm_kernel_irq_routing_entry *e = NULL;
+ unsigned i;
+ int r;
+
+ for (i = 0; i < nr; ++i) {
+ r = -EINVAL;
+ if (ue->gsi >= KVM_MAX_IRQ_ROUTES)
+ goto out;
+ if (ue->flags)
+ goto out;
+ r = -ENOMEM;
+ e = kzalloc(sizeof(*e), GFP_KERNEL);
+ if (!e)
+ goto out;
+ r = setup_routing_entry(e, ue);
+ if (r)
+ goto out;
+ ++ue;
+ list_add(&e->link, &irq_list);
+ e = NULL;
+ }
+
+ mutex_lock(&kvm->lock);
+ list_splice(&kvm->irq_routing, &tmp);
+ INIT_LIST_HEAD(&kvm->irq_routing);
+ list_splice(&irq_list, &kvm->irq_routing);
+ INIT_LIST_HEAD(&irq_list);
+ list_splice(&tmp, &irq_list);
+ mutex_unlock(&kvm->lock);
+
+ r = 0;
+
+out:
+ kfree(e);
+ __kvm_free_irq_routing(&irq_list);
+ return r;
+}
+
+#define IOAPIC_ROUTING_ENTRY(irq) \
+ { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
+ .u.irqchip.irqchip = KVM_IRQCHIP_IOAPIC, .u.irqchip.pin = (irq) }
+#define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
+
+#ifdef CONFIG_X86
+#define SELECT_PIC(irq) \
+ ((irq) < 8 ? KVM_IRQCHIP_PIC_MASTER : KVM_IRQCHIP_PIC_SLAVE)
+# define PIC_ROUTING_ENTRY(irq) \
+ { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
+ .u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }
+# define ROUTING_ENTRY2(irq) \
+ IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
+#else
+# define ROUTING_ENTRY2(irq) \
+ IOAPIC_ROUTING_ENTRY(irq)
+#endif
+
+static const struct kvm_irq_routing_entry default_routing[] = {
+ ROUTING_ENTRY2(0), ROUTING_ENTRY2(1),
+ ROUTING_ENTRY2(2), ROUTING_ENTRY2(3),
+ ROUTING_ENTRY2(4), ROUTING_ENTRY2(5),
+ ROUTING_ENTRY2(6), ROUTING_ENTRY2(7),
+ ROUTING_ENTRY2(8), ROUTING_ENTRY2(9),
+ ROUTING_ENTRY2(10), ROUTING_ENTRY2(11),
+ ROUTING_ENTRY2(12), ROUTING_ENTRY2(13),
+ ROUTING_ENTRY2(14), ROUTING_ENTRY2(15),
+ ROUTING_ENTRY1(16), ROUTING_ENTRY1(17),
+ ROUTING_ENTRY1(18), ROUTING_ENTRY1(19),
+ ROUTING_ENTRY1(20), ROUTING_ENTRY1(21),
+ ROUTING_ENTRY1(22), ROUTING_ENTRY1(23),
+#ifdef CONFIG_IA64
+ ROUTING_ENTRY1(24), ROUTING_ENTRY1(25),
+ ROUTING_ENTRY1(26), ROUTING_ENTRY1(27),
+ ROUTING_ENTRY1(28), ROUTING_ENTRY1(29),
+ ROUTING_ENTRY1(30), ROUTING_ENTRY1(31),
+ ROUTING_ENTRY1(32), ROUTING_ENTRY1(33),
+ ROUTING_ENTRY1(34), ROUTING_ENTRY1(35),
+ ROUTING_ENTRY1(36), ROUTING_ENTRY1(37),
+ ROUTING_ENTRY1(38), ROUTING_ENTRY1(39),
+ ROUTING_ENTRY1(40), ROUTING_ENTRY1(41),
+ ROUTING_ENTRY1(42), ROUTING_ENTRY1(43),
+ ROUTING_ENTRY1(44), ROUTING_ENTRY1(45),
+ ROUTING_ENTRY1(46), ROUTING_ENTRY1(47),
+#endif
+};
+
+int kvm_setup_default_irq_routing(struct kvm *kvm)
+{
+ return kvm_set_irq_routing(kvm, default_routing,
+ ARRAY_SIZE(default_routing), 0);
+}
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;
}