KVM: Add MSI-X interrupt injection logic

We have to handle more than one interrupt with one handler for MSI-X. Avi
suggested to use a flag to indicate the pending. So here is it.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 432edc2..3832243 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -319,6 +319,7 @@ struct kvm_irq_ack_notifier {
        void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
 };
 
+#define KVM_ASSIGNED_MSIX_PENDING              0x1
 struct kvm_guest_msix_entry {
        u32 vector;
        u16 entry;

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1ceb969..8bd44d6 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -95,25 +95,69 @@ static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *h
        return NULL;
 }
 
+static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
+                                   *assigned_dev, int irq)
+{
+       int i, index;
+       struct msix_entry *host_msix_entries;
+
+       host_msix_entries = assigned_dev->host_msix_entries;
+
+       index = -1;
+       for (i = 0; i < assigned_dev->entries_nr; i++)
+               if (irq == host_msix_entries[i].vector) {
+                       index = i;
+                       break;
+               }
+       if (index < 0) {
+               printk(KERN_WARNING "Fail to find correlated MSI-X entry!\n");
+               return 0;
+       }
+
+       return index;
+}
+
 static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
 {
        struct kvm_assigned_dev_kernel *assigned_dev;
+       struct kvm *kvm;
+       int irq, i;
 
        assigned_dev = container_of(work, struct kvm_assigned_dev_kernel,
                                    interrupt_work);
+       kvm = assigned_dev->kvm;
 
        /* This is taken to safely inject irq inside the guest. When
         * the interrupt injection (or the ioapic code) uses a
         * finer-grained lock, update this
         */
-       mutex_lock(&assigned_dev->kvm->lock);
-       kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
-                   assigned_dev->guest_irq, 1);
-
-       if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_GUEST_MSI) {
-               enable_irq(assigned_dev->host_irq);
-               assigned_dev->host_irq_disabled = false;
+       mutex_lock(&kvm->lock);
+       if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_MSIX) {
+               struct kvm_guest_msix_entry *guest_entries =
+                       assigned_dev->guest_msix_entries;
+               for (i = 0; i < assigned_dev->entries_nr; i++) {
+                       if (!(guest_entries[i].flags &
+                                       KVM_ASSIGNED_MSIX_PENDING))
+                               continue;
+                       guest_entries[i].flags &= ~KVM_ASSIGNED_MSIX_PENDING;
+                       kvm_set_irq(assigned_dev->kvm,
+                                   assigned_dev->irq_source_id,
+                                   guest_entries[i].vector, 1);
+                       irq = assigned_dev->host_msix_entries[i].vector;
+                       if (irq != 0)
+                               enable_irq(irq);
+                       assigned_dev->host_irq_disabled = false;
+               }
+       } else {
+               kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
+                           assigned_dev->guest_irq, 1);
+               if (assigned_dev->irq_requested_type &
+                               KVM_ASSIGNED_DEV_GUEST_MSI) {
+                       enable_irq(assigned_dev->host_irq);
+                       assigned_dev->host_irq_disabled = false;
+               }
        }
+
        mutex_unlock(&assigned_dev->kvm->lock);
 }
 
@@ -122,6 +166,14 @@ static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
        struct kvm_assigned_dev_kernel *assigned_dev =
                (struct kvm_assigned_dev_kernel *) dev_id;
 
+       if (assigned_dev->irq_requested_type == KVM_ASSIGNED_DEV_MSIX) {
+               int index = find_index_from_host_irq(assigned_dev, irq);
+               if (index < 0)
+                       return IRQ_HANDLED;
+               assigned_dev->guest_msix_entries[index].flags |=
+                       KVM_ASSIGNED_MSIX_PENDING;
+       }
+
        schedule_work(&assigned_dev->interrupt_work);
 
        disable_irq_nosync(irq);