[PATCH v1 2/4] virtio-pci:add support for configure interrupt

[Cindy Lu <lulu@redhat.com>]

Add support for configure interrupt, use kvm_irqfd_assign and set the
gsi to kernel. When the configure notifier was eventfd_signal by host
kernel, this will finally inject an msix interrupt to guest

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 hw/virtio/virtio-pci.c         | 93 ++++++++++++++++++++++++++++++++++
 include/hw/virtio/virtio-bus.h |  2 +
 2 files changed, 95 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 36524a5728..f8053e1fab 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -762,6 +762,98 @@ undo:
     return ret;
 }
 
+ static int kvm_virtio_pci_config_irqfd_use(VirtIOPCIProxy *proxy,
+                                 unsigned int vector)
+{
+    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    EventNotifier *n = virtio_queue_get_config_notifier(vdev);
+    assert(irqfd);
+    return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, irqfd->virq);
+}
+
+static void kvm_virtio_pci_config_irqfd_release(VirtIOPCIProxy *proxy,
+                                      unsigned int vector)
+{
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    EventNotifier *n = virtio_queue_get_config_notifier(vdev);
+    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+    assert(irqfd);
+    kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, irqfd->virq);
+    return;
+}
+static int kvm_virtio_pci_config_vector_use(VirtIOPCIProxy *proxy,
+                                        unsigned int vector)
+{
+    VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+    int ret;
+
+    if (irqfd->users == 0) {
+        ret = kvm_irqchip_add_msi_route(kvm_state, vector, &proxy->pci_dev);
+        if (ret < 0) {
+            return ret;
+        }
+        irqfd->virq = ret;
+    }
+    irqfd->users++;
+
+    return 0;
+}
+static int kvm_virtio_pci_vector_config_use(VirtIOPCIProxy *proxy)
+{
+
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    unsigned int vector;
+    int ret;
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+    vector = vdev->config_vector ;
+    ret = kvm_virtio_pci_config_vector_use(proxy, vector);
+    if (ret < 0) {
+        goto undo;
+    }
+    ret = kvm_virtio_pci_config_irqfd_use(proxy,  vector);
+    if (ret < 0) {
+        goto undo;
+    }
+    return 0;
+undo:
+    kvm_virtio_pci_config_irqfd_release(proxy, vector);
+    return ret;
+}
+static void kvm_virtio_pci_vector_config_release(VirtIOPCIProxy *proxy)
+{
+    PCIDevice *dev = &proxy->pci_dev;
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    unsigned int vector;
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    vector = vdev->config_vector ;
+    if (vector >= msix_nr_vectors_allocated(dev)) {
+        return;
+    }
+    kvm_virtio_pci_config_irqfd_release(proxy, vector);
+    kvm_virtio_pci_vq_vector_release(proxy, vector);
+}
+
+static int virtio_pci_set_guest_config_notifier(DeviceState *d,  bool assign,
+                                         bool with_irqfd)
+{
+    VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    EventNotifier *notifier = virtio_queue_get_config_notifier(vdev);
+    int r = 0;
+    if (assign) {
+        r = event_notifier_init(notifier, 1);
+        virtio_set_config_notifier_fd_handler(vdev, true, with_irqfd);
+        kvm_virtio_pci_vector_config_use(proxy);
+    } else {
+        virtio_set_config_notifier_fd_handler(vdev, false, with_irqfd);
+        kvm_virtio_pci_vector_config_release(proxy);
+        event_notifier_cleanup(notifier);
+    }
+    return r;
+}
+
 static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
 {
     PCIDevice *dev = &proxy->pci_dev;
@@ -2137,6 +2229,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
     k->ioeventfd_assign = virtio_pci_ioeventfd_assign;
     k->get_dma_as = virtio_pci_get_dma_as;
     k->queue_enabled = virtio_pci_queue_enabled;
+    k->set_config_notifiers = virtio_pci_set_guest_config_notifier;
 }
 
 static const TypeInfo virtio_pci_bus_info = {
diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
index ef8abe49c5..dae81ee414 100644
--- a/include/hw/virtio/virtio-bus.h
+++ b/include/hw/virtio/virtio-bus.h
@@ -93,6 +93,8 @@ struct VirtioBusClass {
      */
     bool has_variable_vring_alignment;
     AddressSpace *(*get_dma_as)(DeviceState *d);
+    int (*set_config_notifiers)(DeviceState *d, bool assign, bool with_irqfd);
+
 };
 
 struct VirtioBusState {
-- 
2.21.3