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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: 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 18:06:06 +02:00 committed by Gleb Natapov
parent 01f2188037
commit 78c634402a
1 changed files with 26 additions and 10 deletions
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36
virt/kvm/assigned-dev.c
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@ -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)
{