On Thu, Nov 19, 2015 at 01:59:05PM -0800, Andy Lutomirski wrote: > On Nov 19, 2015 5:45 AM, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > > On Tue, Oct 27, 2015 at 11:38:57PM -0700, Andy Lutomirski wrote: > > > This switches virtio to use the DMA API unconditionally. I'm sure > > > it breaks things, but it seems to work on x86 using virtio-pci, with > > > and without Xen, and using both the modern 1.0 variant and the > > > legacy variant. > > > > So thinking hard about it, I don't see any real drawbacks to making this > > conditional on a new feature bit, that Xen can then set.. > > Can you elaborate? If I run QEMU, hosting Xen, hosting Linux, and the > virtio device is provided by QEMU, then how does Xen set the bit? You would run QEMU with the appropriate flag. E.g. -global virtio-pci,use_platform_dma=on > Similarly, how would Xen set the bit for a real physical device? > > > --Andy There's no need to set bits for physical devices I think: from security point of view, using them from a VM isn't very different from using them from host. -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
