On 23/11/2018 21:56, Michael S. Tsirkin wrote:
>> +config VIRTIO_IOMMU
>> + bool "Virtio IOMMU driver"
>> + depends on VIRTIO=y
>> + select IOMMU_API
>> + select INTERVAL_TREE
>> + select ARM_DMA_USE_IOMMU if ARM
>> + help
>> + Para-virtualised IOMMU driver with virtio.
>> +
>> + Say Y here if you intend to run this kernel as a guest.
>> +
>
> Given it is arm specific right now, shouldn't this depend on ARM?
> E.g. there's a hack for x86 right now.
Sure, I'll make it depend on ARM64 for now
[..]
>> +static int viommu_probe(struct virtio_device *vdev)
>> +{
>> + struct device *parent_dev = vdev->dev.parent;
>> + struct viommu_dev *viommu = NULL;
>> + struct device *dev = &vdev->dev;
>> + u64 input_start = 0;
>> + u64 input_end = -1UL;
>> + int ret;
>> +
>> + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
>> + !virtio_has_feature(vdev, VIRTIO_IOMMU_F_MAP_UNMAP))
>
> Why bother with a feature bit for this then btw?
We'll need a new feature bit for sharing page tables with the hardware,
because they require different requests (attach_table/invalidate instead
of map/unmap.) A future device supporting page table sharing won't
necessarily need to support map/unmap.
Thanks,
Jean
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