[RFC PATCH 2/4] virtio-pci: add handling of ATS state change

[Viktor Prutyanov]

Guest may enable or disable ATS for the device. Add logic for handling
these events.

Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
---
 hw/virtio/virtio-pci.c     | 12 ++++++++++++
 include/hw/virtio/virtio.h |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 247325c193..70f63a4986 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1731,6 +1731,17 @@ static void virtio_pci_device_write(void *opaque, hwaddr 
addr,
     }
 }
 
+static void virtio_pci_ats_ctrl_trigger(PCIDevice *pci_dev, bool enable)
+{
+    VirtIOPCIProxy *proxy = VIRTIO_PCI(pci_dev);
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+
+    vdev->ats_enabled = enable;
+
+    if (vdev->ats_ctrl_trigger)
+        vdev->ats_ctrl_trigger(enable, vdev);
+}
+
 static void virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy,
                                            const char *vdev_name)
 {
@@ -2166,6 +2177,7 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error 
**errp)
         if (proxy->flags & VIRTIO_PCI_FLAG_ATS) {
             pcie_ats_init(pci_dev, last_pcie_cap_offset,
                           proxy->flags & VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED);
+            pci_dev->ats_ctrl_trigger = virtio_pci_ats_ctrl_trigger;
             last_pcie_cap_offset += PCI_EXT_CAP_ATS_SIZEOF;
         }
 
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 77c6c55929..2812561aae 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -155,6 +155,8 @@ struct VirtIODevice
     QLIST_HEAD(, VirtQueue) *vector_queues;
     QTAILQ_ENTRY(VirtIODevice) next;
     EventNotifier config_notifier;
+    void (*ats_ctrl_trigger)(bool enable, VirtIODevice *vdev);
+    bool ats_enabled;
 };
 
 struct VirtioDeviceClass {
-- 
2.21.0