On 2019/9/27 下午4:04, Tiwei Bie wrote:

On Fri, Sep 27, 2019 at 03:14:42PM +0800, Jason Wang wrote:

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On 2019/9/27 下午12:54, Tiwei Bie wrote:

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+
+		/*
+		 * In vhost-mdev, userspace should pass ring addresses
+		 * in guest physical addresses when IOMMU is disabled or
+		 * IOVAs when IOMMU is enabled.
+		 */

A question here, consider we're using noiommu mode. If guest physical
address is passed here, how can a device use that?

I believe you meant "host physical address" here? And it also have the
implication that the HPA should be continuous (e.g using hugetlbfs).

The comment is talking about the virtual IOMMU (i.e. iotlb in vhost).
It should be rephrased to cover the noiommu case as well. Thanks for
spotting this.

So the question still, if GPA is passed how can it be used by the
virtio-mdev device?

Sorry if I didn't make it clear..
Of course, GPA can't be passed in noiommu mode.

I see.

Thanks for the confirmation.

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Thanks