Re: [PATCH v5 07/12] hw/arm/virt: Reject instantiation of multiple IOMMUs

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 20 Oct 2021 18:27:41 +0100
Jean-Philippe Brucker <jean-philippe@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.auger@redhat.com>
> Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/arm/virt.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 3da7a86e37..25db8d4262 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2441,6 +2441,11 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>          hwaddr db_start = 0, db_end = 0;
>          char *resv_prop_str;
>  
> +        if (vms->iommu != VIRT_IOMMU_NONE) {
> +            error_setg(errp, "virt machine does not support multiple IOMMUs");
> +            return;
> +        }
> +
>          switch (vms->msi_controller) {
>          case VIRT_MSI_CTRL_NONE:
>              return;