vfio-pci: Enable PCIe extended config space

We don't know pre-init time whether the device we're exposing is PCIe or legacy PCI. We could ask for it to be specified via a device option, but that seems like too much to ask of the user. Instead we can assume everything will be PCIe, which makes PCI-core allocate enough config space. Removing the flag during init leaves the space allocated, but allows legacy PCI devices to report the real device config space size to rest of Qemu.

Signed-off-by Alex Williamson <[email protected]>

---
 hw/vfio_pci.c |    4 ++++
 1 file changed, 4 insertions(+)

hw/vfio_pci.c +4 -0

index c51ae67..66537b7 100644
@@ -1899,6 +1899,9 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
             (unsigned long)reg_info.flags);
 
     vdev->config_size = reg_info.size;
+    if (vdev->config_size == PCI_CONFIG_SPACE_SIZE) {
+        vdev->pdev.cap_present &= ~QEMU_PCI_CAP_EXPRESS;
+    }
     vdev->config_offset = reg_info.offset;
 
 error:

@@ -2121,6 +2124,7 @@ static void vfio_pci_dev_class_init(ObjectClass *klass, void *data)
     pdc->exit = vfio_exitfn;
     pdc->config_read = vfio_pci_read_config;
     pdc->config_write = vfio_pci_write_config;
+    pdc->is_express = 1; /* We might be */
 }
 
 static const TypeInfo vfio_pci_dev_info = {