Messages in this thread |  | | Subject | Re: [RFC] virtio: Use DMA MAP API for devices without an IOMMU | From | Benjamin Herrenschmidt <> | Date | Fri, 06 Apr 2018 07:18:33 +1000 |
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On Thu, 2018-04-05 at 21:34 +0300, Michael S. Tsirkin wrote: > > In this specific case, because that would make qemu expect an iommu, > > and there isn't one. > > > I think that you can set iommu_platform in qemu without an iommu.
No I mean the platform has one but it's not desirable for it to be used due to the performance hit.
Cheers, Ben. > > > Anshuman, you need to provide more background here. I don't have time > > right now it's late, but explain about the fact that this is for a > > specific type of secure VM which has only a limited pool of (insecure) > > memory that can be shared with qemu, so all IOs need to bounce via that > > pool, which can be achieved by using swiotlb. > > > > Note: this isn't urgent, we can discuss alternative approaches, this is > > just to start the conversation. > > > > Cheers, > > Ben.
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