[Qemu-devel] [PATCH V2] 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.

Devices plugged directly into the Root Complex as
Integrated Endpoints remain PCI.

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

v1 -> v2:
 - Addressed Michael S. Tsirkin's comments:
   - Added the minimum required capabilities for PCIe devices
   - Integrated Endpoints remain PCI

 - Use pcie_endpoint_cap_init instead of manually creating the pcie capability.

 - Regarding Gerd Hoffman's comments:
   - Creating virtio-pcie devices:
     For the moment I prefer to not duplicate the virtio definitions,
     at least until we don't have a consensus (Personally I don't like it)
   - Removing the IO bar:
     This would be my next patch on the "virtio to express" series, I plan
     to remove it only for "modern" devices.

Any comments would be appreciated,
Thanks,
Marcel

 hw/virtio/virtio-pci.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index f55dd2b..12d0ebb 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1592,6 +1592,25 @@ 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)
+        && !pci_bus_is_root(pci_dev->bus)) {
+        int pos;
+
+        pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
+        pos = pcie_endpoint_cap_init(pci_dev, 0);
+        assert(pos > 0);
+
+        pos = pci_add_capability(pci_dev, PCI_CAP_ID_PM, 0, PCI_PM_SIZEOF);
+        assert(pos > 0);
+
+        /*
+         * Indicates that this function complies with revision 1.2 of the
+         * PCI Power Management Interface Specification.
+         */
+        pci_set_word(pci_dev->config + pos + PCI_PM_PMC, 0x3);
+    }
+
     virtio_pci_bus_new(&proxy->bus, sizeof(proxy->bus), proxy);
     if (k->realize) {
         k->realize(proxy, errp);
-- 
2.1.0