[Qemu-devel] [PATCH RFC] hw/virtio: Add PCIe capability to virtio devices

[Marcel Apfelbaum <marcel@redhat.com>]

The virtio devices are converted to PCI-Express
if they are plugged into a PCI-Express bus and
the 'modern' protocol is enabled.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
---

This is an RFC because all it does it adds the PCIe capability and nothing more.
I post it early so I can get feedbacks on what is the best way to continue it.

Any comments would be appreciated,
Thanks,
Marcel

 hw/virtio/virtio-pci.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 6703806..f7c93d9 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1591,6 +1591,17 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
 
     address_space_init(&proxy->modern_as, &proxy->modern_cfg, "virtio-pci-cfg-as");
 
+    if (!(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN)
+        && pci_bus_is_express(pci_dev->bus)) {
+        int pos = pci_add_capability(pci_dev, PCI_CAP_ID_EXP, 0,
+                                     PCI_EXP_VER2_SIZEOF);
+
+        if (pos > 0) {
+            pci_dev->exp.exp_cap = pos;
+            pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
+        }
+    }
+
     virtio_pci_bus_new(&proxy->bus, sizeof(proxy->bus), proxy);
     if (k->realize) {
         k->realize(proxy, errp);
-- 
2.1.0