Commit 78c63440 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Gleb Natapov
Browse files

kvm: deliver msi interrupts from irq handler 



We can deliver certain interrupts, notably MSI,
from atomic context.  Use kvm_set_irq_inatomic,
to implement an irq handler for msi.

This reduces the pressure on scheduler in case
where host and guest irq share a host cpu.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 01f21880

virt/kvm/assigned-dev.c

+26 −10
Original line number Diff line number Diff line
@@ -105,6 +105,15 @@ static irqreturn_t kvm_assigned_dev_thread_intx(int irq, void *dev_id) 
}



#ifdef __KVM_HAVE_MSI

static irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)

{

	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;

	int ret = kvm_set_irq_inatomic(assigned_dev->kvm,

				       assigned_dev->irq_source_id,

				       assigned_dev->guest_irq, 1);

	return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;

}



static irqreturn_t kvm_assigned_dev_thread_msi(int irq, void *dev_id)

{

	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
@@ -117,6 +126,23 @@ static irqreturn_t kvm_assigned_dev_thread_msi(int irq, void *dev_id) 
#endif



#ifdef __KVM_HAVE_MSIX

static irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)

{

	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;

	int index = find_index_from_host_irq(assigned_dev, irq);

	u32 vector;

	int ret = 0;



	if (index >= 0) {

		vector = assigned_dev->guest_msix_entries[index].vector;

		ret = kvm_set_irq_inatomic(assigned_dev->kvm,

					   assigned_dev->irq_source_id,

					   vector, 1);

	}



	return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;

}



static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)

{

	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
@@ -334,11 +360,6 @@ static int assigned_device_enable_host_intx(struct kvm *kvm, 
}



#ifdef __KVM_HAVE_MSI

static irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)

{

	return IRQ_WAKE_THREAD;

}



static int assigned_device_enable_host_msi(struct kvm *kvm,

					   struct kvm_assigned_dev_kernel *dev)

{
@@ -363,11 +384,6 @@ static int assigned_device_enable_host_msi(struct kvm *kvm, 
#endif



#ifdef __KVM_HAVE_MSIX

static irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)

{

	return IRQ_WAKE_THREAD;

}



static int assigned_device_enable_host_msix(struct kvm *kvm,

					    struct kvm_assigned_dev_kernel *dev)

{

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