aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorMark McLoughlin <markmc@redhat.com>2008-12-02 12:16:33 +0000
committerAvi Kivity <avi@redhat.com>2008-12-31 16:55:47 +0200
commitdefaf1587c5d7dff828f6f11c8941e5bcef00f50 (patch)
treefe4bcf162e203ee80916a5d168d838ef8aa62d25
parenteb64f1e8cd5c3cae912db30a77d062367f7a11a6 (diff)
downloadmrst-s0i3-test-defaf1587c5d7dff828f6f11c8941e5bcef00f50.tar.gz
mrst-s0i3-test-defaf1587c5d7dff828f6f11c8941e5bcef00f50.tar.xz
mrst-s0i3-test-defaf1587c5d7dff828f6f11c8941e5bcef00f50.zip
KVM: fix handling of ACK from shared guest IRQ
If an assigned device shares a guest irq with an emulated device then we currently interpret an ack generated by the emulated device as originating from the assigned device leading to e.g. "Unbalanced enable for IRQ 4347" from the enable_irq() in kvm_assigned_dev_ack_irq(). The fix is fairly simple - don't enable the physical device irq unless it was previously disabled. Of course, this can still lead to a situation where a non-assigned device ACK can cause the physical device irq to be reenabled before the device was serviced. However, being level sensitive, the interrupt will merely be regenerated. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
-rw-r--r--include/linux/kvm_host.h1
-rw-r--r--virt/kvm/kvm_main.c15
2 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 8091a4d90dd..eafabd5c66b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -307,6 +307,7 @@ struct kvm_assigned_dev_kernel {
int host_busnr;
int host_devfn;
int host_irq;
+ bool host_irq_disabled;
int guest_irq;
struct msi_msg guest_msi;
#define KVM_ASSIGNED_DEV_GUEST_INTX (1 << 0)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index eb70ca6c714..fc6127cbea1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -170,6 +170,7 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
KVM_ASSIGNED_DEV_GUEST_MSI) {
assigned_device_msi_dispatch(assigned_dev);
enable_irq(assigned_dev->host_irq);
+ assigned_dev->host_irq_disabled = false;
}
mutex_unlock(&assigned_dev->kvm->lock);
kvm_put_kvm(assigned_dev->kvm);
@@ -181,8 +182,12 @@ static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
(struct kvm_assigned_dev_kernel *) dev_id;
kvm_get_kvm(assigned_dev->kvm);
+
schedule_work(&assigned_dev->interrupt_work);
+
disable_irq_nosync(irq);
+ assigned_dev->host_irq_disabled = true;
+
return IRQ_HANDLED;
}
@@ -196,8 +201,16 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
dev = container_of(kian, struct kvm_assigned_dev_kernel,
ack_notifier);
+
kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);
- enable_irq(dev->host_irq);
+
+ /* The guest irq may be shared so this ack may be
+ * from another device.
+ */
+ if (dev->host_irq_disabled) {
+ enable_irq(dev->host_irq);
+ dev->host_irq_disabled = false;
+ }
}
static void kvm_free_assigned_irq(struct kvm *kvm,