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Commit 399ec807 authored by Avi Kivity's avatar Avi Kivity
Browse files

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: default avatarAvi Kivity <avi@redhat.com>
parent 19355475

arch/ia64/kvm/kvm-ia64.c

+5 −0
Original line number Diff line number Diff line
@@ -919,6 +919,11 @@ long kvm_arch_vm_ioctl(struct file *filp, 
		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;

arch/x86/kvm/x86.c

+6 −0
Original line number Diff line number Diff line
@@ -1835,6 +1835,12 @@ long kvm_arch_vm_ioctl(struct file *filp, 
			}

		} 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);

include/linux/kvm.h

+33 −0
Original line number Diff line number Diff line
@@ -398,6 +398,38 @@ struct kvm_trace_rec { 
#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



/*
@@ -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)

#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)

include/linux/kvm_host.h

+31 −0
Original line number Diff line number Diff line
@@ -107,6 +107,19 @@ struct kvm_memory_slot { 
	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;
@@ -128,6 +141,7 @@ struct kvm { 
#endif



#ifdef CONFIG_HAVE_KVM_IRQCHIP

	struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */

	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



#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

virt/kvm/irq_comm.c

+164 −4
Original line number Diff line number Diff line
@@ -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 @@ 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.

	 */

	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 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool 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);

}