[PATCH 11/42] KVM: Maintain back mapping from irqchip/pin to gsi

Avi Kivity
2009-11-16T12:21:15Z

From: Gleb Natapov <gleb@redhat.com>

Maintain back mapping from irqchip/pin to gsi to speedup
interrupt acknowledgment notifications.

[avi: build fix on non-x86/ia64]

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/ia64/include/asm/kvm.h | 1 +
arch/x86/include/asm/kvm.h | 1 +
include/linux/kvm_host.h | 9 +++++++++
virt/kvm/irq_comm.c | 31 ++++++++++++++-----------------
4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/arch/ia64/include/asm/kvm.h b/arch/ia64/include/asm/kvm.h
index 18a7e49..bc90c75 100644
--- a/arch/ia64/include/asm/kvm.h
+++ b/arch/ia64/include/asm/kvm.h
@@ -60,6 +60,7 @@ struct kvm_ioapic_state {
#define KVM_IRQCHIP_PIC_MASTER 0
#define KVM_IRQCHIP_PIC_SLAVE 1
#define KVM_IRQCHIP_IOAPIC 2
+#define KVM_NR_IRQCHIPS 3

#define KVM_CONTEXT_SIZE 8*1024

diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index 4a5fe91..f02e87a 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -79,6 +79,7 @@ struct kvm_ioapic_state {
#define KVM_IRQCHIP_PIC_MASTER 0
#define KVM_IRQCHIP_PIC_SLAVE 1
#define KVM_IRQCHIP_IOAPIC 2
+#define KVM_NR_IRQCHIPS 3

/* for KVM_GET_REGS and KVM_SET_REGS */
struct kvm_regs {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f403e66..cc2d749 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -131,7 +131,10 @@ struct kvm_kernel_irq_routing_entry {
struct hlist_node link;
};

+#ifdef __KVM_HAVE_IOAPIC
+
struct kvm_irq_routing_table {
+ int chip[KVM_NR_IRQCHIPS][KVM_IOAPIC_NUM_PINS];
struct kvm_kernel_irq_routing_entry *rt_entries;
u32 nr_rt_entries;
/*
@@ -141,6 +144,12 @@ struct kvm_irq_routing_table {
struct hlist_head map[0];
};

+#else
+
+struct kvm_irq_routing_table {};
+
+#endif
+
struct kvm {
spinlock_t mmu_lock;
spinlock_t requests_lock;
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 81950f6..59cf8da 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -175,25 +175,16 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
struct kvm_irq_ack_notifier *kian;
struct hlist_node *n;
- unsigned gsi = pin;
- int i;
+ int gsi;

trace_kvm_ack_irq(irqchip, pin);

- for (i = 0; i < kvm->irq_routing->nr_rt_entries; i++) {
- struct kvm_kernel_irq_routing_entry *e;
- e = &kvm->irq_routing->rt_entries[i];
- if (e->type == KVM_IRQ_ROUTING_IRQCHIP &&
- e->irqchip.irqchip == irqchip &&
- e->irqchip.pin == pin) {
- gsi = e->gsi;
- break;
- }
- }
-
- hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list, link)
- if (kian->gsi == gsi)
- kian->irq_acked(kian);
+ gsi = kvm->irq_routing->chip[irqchip][pin];
+ if (gsi != -1)
+ hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list,
+ link)
+ if (kian->gsi == gsi)
+ kian->irq_acked(kian);
}

void kvm_register_irq_ack_notifier(struct kvm *kvm,
@@ -332,6 +323,9 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
}
e->irqchip.irqchip = ue->u.irqchip.irqchip;
e->irqchip.pin = ue->u.irqchip.pin + delta;
+ if (e->irqchip.pin >= KVM_IOAPIC_NUM_PINS)
+ goto out;
+ rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
break;
case KVM_IRQ_ROUTING_MSI:
e->set = kvm_set_msi;
@@ -356,7 +350,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
unsigned flags)
{
struct kvm_irq_routing_table *new, *old;
- u32 i, nr_rt_entries = 0;
+ u32 i, j, nr_rt_entries = 0;
int r;

for (i = 0; i < nr; ++i) {
@@ -377,6 +371,9 @@ int kvm_set_irq_routing(struct kvm *kvm,
new->rt_entries = (void *)&new->map[nr_rt_entries];

new->nr_rt_entries = nr_rt_entries;
+ for (i = 0; i < 3; i++)
+ for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
+ new->chip[i][j] = -1;

for (i = 0; i < nr; ++i) {
r = -EINVAL;
--
1.6.5.2