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| author | Michael S. Tsirkin <mst@redhat.com> | 2012-10-17 18:06:06 +0200 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2012-12-05 15:10:53 +0200 |
| commit | 78c634402a1825f1f5bef13077f0985f3b8a3212 (patch) | |
| tree | 1dac3b54821c39c1b893f0a2db4806dacc917bdc /virt/kvm/assigned-dev.c | |
| parent | 01f218803757c9ec1152ac2fd39d03c27c452634 (diff) | |
| download | lwn-78c634402a1825f1f5bef13077f0985f3b8a3212.tar.gz lwn-78c634402a1825f1f5bef13077f0985f3b8a3212.zip | |
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>
Diffstat (limited to 'virt/kvm/assigned-dev.c')
| -rw-r--r-- | virt/kvm/assigned-dev.c | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c index 23a41a9f8db9..3642239252b0 100644 --- a/virt/kvm/assigned-dev.c +++ b/virt/kvm/assigned-dev.c @@ -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) { |