[PATCH v3 04/10] hw/arm/virt: Reject instantiation of multiple IOMMUs

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

We do not support instantiating multiple IOMMUs. Before adding a
virtio-iommu, check that no other IOMMU is present. This will detect
both "iommu=smmuv3" machine parameter and another virtio-iommu instance.

Fixes: 70e89132c9 ("hw/arm/virt: Add the virtio-iommu device tree mappings")
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 hw/arm/virt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index f238766aa1..26069f943a 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2471,6 +2471,11 @@ static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
     if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
         PCIDevice *pdev = PCI_DEVICE(dev);
 
+        if (vms->iommu != VIRT_IOMMU_NONE) {
+            error_setg(errp, "virt machine does not support multiple IOMMUs");
+            return;
+        }
+
         vms->iommu = VIRT_IOMMU_VIRTIO;
         vms->virtio_iommu_bdf = pci_get_bdf(pdev);
         create_virtio_iommu_dt_bindings(vms);
-- 
2.33.0