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authorMichael S. Tsirkin <mst@redhat.com>2012-10-17 18:06:02 +0200
committerGleb Natapov <gleb@redhat.com>2012-12-05 15:10:45 +0200
commit01f218803757c9ec1152ac2fd39d03c27c452634 (patch)
treee64afc26da5c1a1b1b434cf7fda755ddaf436892
parent45e3cc7d9fe69844cd12d51c511e1e98d156bbe1 (diff)
downloadvexpress-lsk-01f218803757c9ec1152ac2fd39d03c27c452634.tar.gz
kvm: add kvm_set_irq_inatomic
Add an API to inject IRQ from atomic context. Return EWOULDBLOCK if impossible (e.g. for multicast). Only MSI is supported ATM. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
-rw-r--r--include/linux/kvm_host.h1
-rw-r--r--virt/kvm/irq_comm.c83
2 files changed, 72 insertions, 12 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 8e5c7b65165..36c3704bfa7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -693,6 +693,7 @@ 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_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level);
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 2eb58af7ee9..656fa455e15 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -102,6 +102,23 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
return r;
}
+static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm_lapic_irq *irq)
+{
+ trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
+
+ irq->dest_id = (e->msi.address_lo &
+ MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
+ irq->vector = (e->msi.data &
+ MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
+ irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
+ irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
+ irq->delivery_mode = e->msi.data & 0x700;
+ irq->level = 1;
+ irq->shorthand = 0;
+ /* TODO Deal with RH bit of MSI message address */
+}
+
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
struct kvm *kvm, int irq_source_id, int level)
{
@@ -110,22 +127,26 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
if (!level)
return -1;
- trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
+ kvm_set_msi_irq(e, &irq);
- irq.dest_id = (e->msi.address_lo &
- MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
- irq.vector = (e->msi.data &
- MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
- irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
- irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
- irq.delivery_mode = e->msi.data & 0x700;
- irq.level = 1;
- irq.shorthand = 0;
-
- /* TODO Deal with RH bit of MSI message address */
return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
}
+
+static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm)
+{
+ struct kvm_lapic_irq irq;
+ int r;
+
+ kvm_set_msi_irq(e, &irq);
+
+ if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r))
+ return r;
+ else
+ return -EWOULDBLOCK;
+}
+
int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
{
struct kvm_kernel_irq_routing_entry route;
@@ -178,6 +199,44 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
return ret;
}
+/*
+ * Deliver an IRQ in an atomic context if we can, or return a failure,
+ * user can retry in a process context.
+ * Return value:
+ * -EWOULDBLOCK - Can't deliver in atomic context: retry in a process context.
+ * Other values - No need to retry.
+ */
+int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level)
+{
+ struct kvm_kernel_irq_routing_entry *e;
+ int ret = -EINVAL;
+ struct kvm_irq_routing_table *irq_rt;
+ struct hlist_node *n;
+
+ trace_kvm_set_irq(irq, level, irq_source_id);
+
+ /*
+ * Injection into either PIC or IOAPIC might need to scan all CPUs,
+ * which would need to be retried from thread context; when same GSI
+ * is connected to both PIC and IOAPIC, we'd have to report a
+ * partial failure here.
+ * Since there's no easy way to do this, we only support injecting MSI
+ * which is limited to 1:1 GSI mapping.
+ */
+ 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) {
+ if (likely(e->type == KVM_IRQ_ROUTING_MSI))
+ ret = kvm_set_msi_inatomic(e, kvm);
+ else
+ ret = -EWOULDBLOCK;
+ break;
+ }
+ rcu_read_unlock();
+ return ret;
+}
+
void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
struct kvm_irq_ack_notifier *kian;