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>

2 files changed, 60 insertions, 7 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 432edc27e82b..3832243625d4 100644
--- 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 1ceb96901f32..8bd44d6985c7 100644
--- 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);