Il 03/09/2014 17:07, Andy Lutomirski ha scritto: >> > Yes, only for virtio---but for x86 I think it should be off by default, >> > even if that means virtio+IOMMU requires a new kernel. > Just to clarify: is "it" the direct-ram-access property? If so, I > think I might agree.
Yes. > Alternatively, could QEMU easily teach the IOMMU code to generate the > ACPI tables such that virtio-pci devices aren't advertised as living > behind the IOMMU? This would work both with and without my patches. > On the other hand, maybe this gets complicated when hotplug is > involved. That could be possible. For hot-plug, you can simply forbid hotplugging with direct-ram-access=on. If you want hotplug, then we should add the direct-ram-access property to PCI bridges too (with the same limitation on hotplug). All devices under such a bridge would be outside the IOMMU, including virtio devices with direct-ram-access=off. Paolo _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
