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Commit 01f21880 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Gleb Natapov
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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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 45e3cc7d

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

virt/kvm/irq_comm.c

+71 −12
Original line number Diff line number Diff line
@@ -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);



	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;

	kvm_set_msi_irq(e, &irq);



	/* 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;