On Fri, Nov 20, 2015 at 08:56:46AM +0200, Michael S. Tsirkin wrote: > On Thu, Nov 19, 2015 at 01:59:05PM -0800, Andy Lutomirski wrote: > > On Nov 19, 2015 5:45 AM, "Michael S. Tsirkin" <m...@redhat.com> 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
Or Xen code within QEMU can tweak this global internally so users don't need to care. > > 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 linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
