Re: [Qemu-devel] [PATCH for 2.8 02/11] virtio: convert to use DMA api

[Wei Xu <wexu@redhat.com>]

On 2016年08月30日 11:06, Jason Wang wrote:
> @@ -1587,6 +1595,11 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
>       }
>
>       if (legacy) {
> +        if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
> +            error_setg(errp, "VIRTIO_F_IOMMU_PLATFORM was supported by"
> +                       "neither legacy nor transitional device.");
> +            return ;
> +        }

Not sure if i understand it correctly, the transitional device here 
maybe a bit hard to understand, just a tip for your convenience,
besides the denied prompt, can we add what kind of device is supported 
to the message? such as modern device only, like this.

"VIRTIO_F_IOMMU_PLATFORM is supported by modern device only, it
is not supported by either legacy or transitional device."

>           /* legacy and transitional */
>           pci_set_word(config + PCI_SUBSYSTEM_VENDOR_ID,
>                        pci_get_word(config + PCI_VENDOR_ID));