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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>
This commit is contained in:
Michael S. Tsirkin 2012-10-17 18:06:02 +02:00 committed by Gleb Natapov
parent 45e3cc7d9f
commit 01f2188037
2 changed files with 72 additions and 12 deletions
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1
include/linux/kvm_host.h
View File

@ -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);

83
virt/kvm/irq_comm.c
View File

@ -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;