The qemuValidateDomainDeviceDefControllerPCI() function is
called if PCI controllers are present in the domain
configuration, which shouldn't happen if the machine type
doesn't support PCI. If we somehow find ourselves in that
scenario, reporting an error would be the right thing to do.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
---
 src/qemu/qemu_validate.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index adba3e4a89..ebcc9b8e8e 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -3975,6 +3975,13 @@ qemuValidateDomainDeviceDefControllerPCI(const virDomainControllerDef *cont,
         return -1;
     }
 
+    if (!qemuDomainSupportsPCI(def)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("Machine type '%1$s' does not support PCI"),
+                       def->os.machine);
+        return -1;
+    }
+
     /* modelName */
     switch ((virDomainControllerModelPCI) cont->model) {
     case VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE:
-- 
2.50.1

On Tue, Aug 19, 2025 at 18:22:20 +0200, Andrea Bolognani via Devel wrote:
> The qemuValidateDomainDeviceDefControllerPCI() function is
> called if PCI controllers are present in the domain
> configuration, which shouldn't happen if the machine type
> doesn't support PCI. If we somehow find ourselves in that
> scenario, reporting an error would be the right thing to do.
> 
> Signed-off-by: Andrea Bolognani <abologna@redhat.com>
> ---
>  src/qemu/qemu_validate.c | 7 +++++++
>  1 file changed, 7 insertions(+)

Reviewed-by: Peter Krempa <pkrempa@redhat.com>