On Mon, Jul 27, 2015 at 06:08:59PM -0700, 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. > > 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 It's worth thinking about. I'll need to measure what's the overhead of supporting both modes - probably after I'm back from the KVM forum. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
