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/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 1477f91..dbf527a 100644 (file)
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -919,6 +919,11 @@ long kvm_arch_vm_ioctl(struct file *filp,
                r = kvm_ioapic_init(kvm);
                if (r)
                        goto out;
                r = kvm_ioapic_init(kvm);
                if (r)
                        goto out;

+               r = kvm_setup_default_irq_routing(kvm);
+               if (r) {
+                       kfree(kvm->arch.vioapic);
+                       goto out;
+               }

                break;
        case KVM_IRQ_LINE: {
                struct kvm_irq_level irq_event;
                break;
        case KVM_IRQ_LINE: {
                struct kvm_irq_level irq_event;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 141a016..32e3a7e 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1835,6 +1835,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
                        }
                } else
                        goto out;
                        }
                } else
                        goto out;

+               r = kvm_setup_default_irq_routing(kvm);
+               if (r) {
+                       kfree(kvm->arch.vpic);
+                       kfree(kvm->arch.vioapic);
+                       goto out;
+               }

                break;
        case KVM_CREATE_PIT:
                mutex_lock(&kvm->lock);
                break;
        case KVM_CREATE_PIT:
                mutex_lock(&kvm->lock);

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 73f3480..7a5d73a 100644 (file)
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -399,6 +399,38 @@ struct kvm_trace_rec {
 #if defined(CONFIG_X86)
 #define KVM_CAP_REINJECT_CONTROL 24
 #endif
 #if defined(CONFIG_X86)
 #define KVM_CAP_REINJECT_CONTROL 24
 #endif

+#if defined(CONFIG_X86)||defined(CONFIG_IA64)
+#define KVM_CAP_IRQ_ROUTING 25
+#endif
+
+#ifdef KVM_CAP_IRQ_ROUTING
+
+struct kvm_irq_routing_irqchip {
+       __u32 irqchip;
+       __u32 pin;
+};
+
+/* gsi routing entry types */
+#define KVM_IRQ_ROUTING_IRQCHIP 1
+
+struct kvm_irq_routing_entry {
+       __u32 gsi;
+       __u32 type;
+       __u32 flags;
+       __u32 pad;
+       union {
+               struct kvm_irq_routing_irqchip irqchip;
+               __u32 pad[8];
+       } u;
+};
+
+struct kvm_irq_routing {
+       __u32 nr;
+       __u32 flags;
+       struct kvm_irq_routing_entry entries[0];
+};
+
+#endif

 
 /*
  * ioctls for VM fds
 
 /*
  * ioctls for VM fds


@@ -430,6 +462,7 @@ struct kvm_trace_rec {
                        _IOW(KVMIO,  0x68, struct kvm_coalesced_mmio_zone)
 #define KVM_ASSIGN_PCI_DEVICE _IOR(KVMIO, 0x69, \
                                   struct kvm_assigned_pci_dev)
                        _IOW(KVMIO,  0x68, struct kvm_coalesced_mmio_zone)
 #define KVM_ASSIGN_PCI_DEVICE _IOR(KVMIO, 0x69, \
                                   struct kvm_assigned_pci_dev)

+#define KVM_SET_GSI_ROUTING       _IOW(KVMIO, 0x6a, struct kvm_irq_routing)

 #define KVM_ASSIGN_IRQ _IOR(KVMIO, 0x70, \
                            struct kvm_assigned_irq)
 #define KVM_REINJECT_CONTROL      _IO(KVMIO, 0x71)
 #define KVM_ASSIGN_IRQ _IOR(KVMIO, 0x70, \
                            struct kvm_assigned_irq)
 #define KVM_REINJECT_CONTROL      _IO(KVMIO, 0x71)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 99963f3..ce285e0 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -107,6 +107,19 @@ struct kvm_memory_slot {
        int user_alloc;
 };
 
        int user_alloc;
 };
 

+struct kvm_kernel_irq_routing_entry {
+       u32 gsi;
+       void (*set)(struct kvm_kernel_irq_routing_entry *e,
+                   struct kvm *kvm, int level);
+       union {
+               struct {
+                       unsigned irqchip;
+                       unsigned pin;
+               } irqchip;
+       };
+       struct list_head link;
+};
+

 struct kvm {
        struct mutex lock; /* protects the vcpus array and APIC accesses */
        spinlock_t mmu_lock;
 struct kvm {
        struct mutex lock; /* protects the vcpus array and APIC accesses */
        spinlock_t mmu_lock;


@@ -128,6 +141,7 @@ struct kvm {
 #endif
 
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
 #endif
 
 #ifdef CONFIG_HAVE_KVM_IRQCHIP

+       struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */

        struct hlist_head mask_notifier_list;
 #endif
 
        struct hlist_head mask_notifier_list;
 #endif
 


@@ -480,4 +494,21 @@ static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_se
 }
 #endif
 
 }
 #endif
 

+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+
+#define KVM_MAX_IRQ_ROUTES 1024
+
+int kvm_setup_default_irq_routing(struct kvm *kvm);
+int kvm_set_irq_routing(struct kvm *kvm,
+                       const struct kvm_irq_routing_entry *entries,
+                       unsigned nr,
+                       unsigned flags);
+void kvm_free_irq_routing(struct kvm *kvm);
+
+#else
+
+static inline void kvm_free_irq_routing(struct kvm *kvm) {}
+
+#endif
+

 #endif
 #endif

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 5162a41..a797fa5 100644 (file)
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -24,9 +24,24 @@
 
 #include "ioapic.h"
 
 
 #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)
 {
 /* 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 */
        unsigned long *irq_state = (unsigned long *)&kvm->arch.irq_states[irq];
 
        /* Logical OR for level trig interrupt */


@@ -39,10 +54,9 @@ void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
         * IOAPIC.  So set the bit in both. The guest will ignore
         * writes to the unused one.
         */
         * 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)
 }
 
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi)


@@ -123,3 +137,149 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
                        kimn->func(kimn, mask);
 }
 
                        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 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -843,6 +843,7 @@ static struct kvm *kvm_create_vm(void)
        if (IS_ERR(kvm))
                goto out;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
        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
 
        INIT_HLIST_HEAD(&kvm->mask_notifier_list);
 #endif
 


@@ -926,6 +927,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
        spin_lock(&kvm_lock);
        list_del(&kvm->vm_list);
        spin_unlock(&kvm_lock);
        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
        kvm_io_bus_destroy(&kvm->pio_bus);
        kvm_io_bus_destroy(&kvm->mmio_bus);
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET


@@ -1946,6 +1948,36 @@ static long kvm_vm_ioctl(struct file *filp,
                break;
        }
 #endif
                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);
        }
        default:
                r = kvm_arch_vm_ioctl(filp, ioctl, arg);
        }


@@ -2012,6 +2044,10 @@ static long kvm_dev_ioctl_check_extension_generic(long arg)
        case KVM_CAP_USER_MEMORY:
        case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
                return 1;
        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;
        }
        default:
                break;
        }