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Date: Mon, 16 Jul 2012 14:34:03 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: avi@...hat.com, mst@...hat.com
Cc: gleb@...hat.com, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
jan.kiszka@...mens.com
Subject: [PATCH v5 3/4] kvm: Create kvm_clear_irq()
This is an alternative to kvm_set_irq(,,,0) which returns the previous
assertion state of the interrupt and does nothing if it isn't changed.
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
---
include/linux/kvm_host.h | 3 ++
virt/kvm/irq_comm.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 81 insertions(+)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a7661c0..6c168f1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -219,6 +219,8 @@ struct kvm_kernel_irq_routing_entry {
u32 type;
int (*set)(struct kvm_kernel_irq_routing_entry *e,
struct kvm *kvm, int irq_source_id, int level);
+ int (*clear)(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id);
union {
struct {
unsigned irqchip;
@@ -629,6 +631,7 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
unsigned long *deliver_bitmask);
#endif
int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
+int kvm_clear_irq(struct kvm *kvm, int irq_source_id, u32 irq);
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm,
int irq_source_id, int level);
void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 5afb431..76e8f22 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -68,6 +68,42 @@ static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, level);
}
+static inline int kvm_clear_irq_line_state(unsigned long *irq_state,
+ int irq_source_id)
+{
+ return !!test_and_clear_bit(irq_source_id, irq_state);
+}
+
+static int kvm_clear_pic_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id)
+{
+#ifdef CONFIG_X86
+ struct kvm_pic *pic = pic_irqchip(kvm);
+ int level = kvm_clear_irq_line_state(&pic->irq_states[e->irqchip.pin],
+ irq_source_id);
+ if (level)
+ kvm_pic_set_irq(pic, e->irqchip.pin,
+ !!pic->irq_states[e->irqchip.pin]);
+ return level;
+#else
+ return -1;
+#endif
+}
+
+static int kvm_clear_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id)
+{
+ struct kvm_ioapic *ioapic = kvm->arch.vioapic;
+ int level;
+
+ level = kvm_clear_irq_line_state(&ioapic->irq_states[e->irqchip.pin],
+ irq_source_id);
+ if (level)
+ kvm_ioapic_set_irq(ioapic, e->irqchip.pin,
+ !!ioapic->irq_states[e->irqchip.pin]);
+ return level;
+}
+
inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
{
#ifdef CONFIG_IA64
@@ -190,6 +226,45 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
return ret;
}
+/*
+ * Return value:
+ * < 0 Error
+ * = 0 Interrupt was not set, did nothing
+ * > 0 Interrupt was pending, cleared
+ */
+int kvm_clear_irq(struct kvm *kvm, int irq_source_id, u32 irq)
+{
+ struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
+ int ret = -EINVAL, i = 0;
+ struct kvm_irq_routing_table *irq_rt;
+ struct hlist_node *n;
+
+ /* Not possible to detect if the guest uses the PIC or the
+ * IOAPIC. So clear the bit in both. The guest will ignore
+ * writes to the unused one.
+ */
+ rcu_read_lock();
+ irq_rt = rcu_dereference(kvm->irq_routing);
+ if (irq < irq_rt->nr_rt_entries)
+ hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
+ irq_set[i++] = *e;
+ rcu_read_unlock();
+
+ while (i--) {
+ int r = -EINVAL;
+
+ if (irq_set[i].clear)
+ r = irq_set[i].clear(&irq_set[i], kvm, irq_source_id);
+
+ if (r < 0)
+ continue;
+
+ ret = r + ((ret < 0) ? 0 : ret);
+ }
+
+ return ret;
+}
+
void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
struct kvm_irq_ack_notifier *kian;
@@ -344,16 +419,19 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
switch (ue->u.irqchip.irqchip) {
case KVM_IRQCHIP_PIC_MASTER:
e->set = kvm_set_pic_irq;
+ e->clear = kvm_clear_pic_irq;
max_pin = 16;
break;
case KVM_IRQCHIP_PIC_SLAVE:
e->set = kvm_set_pic_irq;
+ e->clear = kvm_clear_pic_irq;
max_pin = 16;
delta = 8;
break;
case KVM_IRQCHIP_IOAPIC:
max_pin = KVM_IOAPIC_NUM_PINS;
e->set = kvm_set_ioapic_irq;
+ e->clear = kvm_clear_ioapic_irq;
break;
default:
goto out;
--
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