On Tue, 14 Sep 2021 15:19:59 +0100
Jean-Philippe Brucker <jean-phili...@linaro.org> wrote:
> 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.au...@redhat.com>
> Signed-off-by: Jean-Philippe Brucker <jean-phili...@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;
> + }
can you move check into 'pre_plug' callback?
(plug should not fail and just finish up whatever was
verified/set by pre_plug, there are plans to remove errp
argument from 'plug' callback)
> +
> vms->iommu = VIRT_IOMMU_VIRTIO;
> vms->virtio_iommu_bdf = pci_get_bdf(pdev);
> create_virtio_iommu_dt_bindings(vms);
