From: Marcel Apfelbaum <marcel@redhat.com>

IO_LIMIT and IO_BASE registers should not be writable if
gen_pcie_root_port's io-reserve property is set to 0.
The COMMAND register should have the IO flag read only.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/pci-bridge/gen_pcie_root_port.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/pci-bridge/gen_pcie_root_port.c b/hw/pci-bridge/gen_pcie_root_port.c
index ed03ffc..ad4e6aa 100644
--- a/hw/pci-bridge/gen_pcie_root_port.c
+++ b/hw/pci-bridge/gen_pcie_root_port.c
@@ -85,6 +85,13 @@ static void gen_rp_realize(DeviceState *dev, Error **errp)
         rpc->parent_class.exit(d);
         return;
     }
+
+    if (!grp->io_reserve) {
+        pci_word_test_and_clear_mask(d->wmask + PCI_COMMAND,
+                                     PCI_COMMAND_IO);
+        d->wmask[PCI_IO_BASE] = 0;
+        d->wmask[PCI_IO_LIMIT] = 0;
+    }
 }
 
 static const VMStateDescription vmstate_rp_dev = {
-- 
MST