On 28/07/2015 03:08, Andy Lutomirski wrote: > On Mon, Sep 1, 2014 at 10:39 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: >> This fixes virtio on Xen guests as well as on any other platform >> that uses virtio_pci on which physical addresses don't match bus >> addresses. >> >> This can be tested with: >> >> virtme-run --xen xen --kimg arch/x86/boot/bzImage --console >> >> using virtme from here: >> >> https://git.kernel.org/cgit/utils/kernel/virtme/virtme.git >> >> Without these patches, the guest hangs forever. With these patches, >> everything works. >> > > Dusting off an ancient thread. > > Now that the dust has accumulated^Wsettled, is it worth pursuing this? > I think the situation is considerably worse than it was when I > originally wrote these patches: I think that QEMU now supports a nasty > mode in which the guest's PCI bus appears to be behind an IOMMU but > the virtio devices on that bus punch straight through that IOMMU. That is an experimental feature (it's x-iommu), so it can change. The plan was: - for PPC, virtio never honors IOMMU - for non-PPC, either have virtio always honor IOMMU, or enforce that virtio is not under IOMMU. Paolo > I have a half-hearted port to modern kernels here: > > https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=virtio_ring_xen > > I didn't implement DMA API access for virtio_pci_modern, and I have no > idea what to do about detecting whether a given virtio device honors > its IOMMU or not. > > --Andy > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
