On Wed, May 07 2014 at 11:10:56 am BST, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: > On 7 May 2014 10:52, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >> On Wed, May 07 2014 at 10:34:30 am BST, Peter Maydell >> <peter.maydell@xxxxxxxxxx> wrote: >>> Current opinion on the qemu-devel thread seems to be that we >>> should just define that the endianness of the virtio device is >>> the endianness of the guest kernel at the point where the guest >>> triggers a reset of the virtio device by writing zero the QueuePFN >>> or Status registers. >> >> On AArch32, we only have the CPSR.E bit to select the endiannes. Are we >> going to simply explode if the access comes from userspace? > > There's SCTLR.EE in AArch32, right? Indeed, good point. >> On AArch64, we can either select the kernel endianness, or userspace >> endianness. Are we going to go a different route just for the sake of >> enforcing kernel access? >> >> I'm inclined to think of userspace access as a valid use case. > > I don't actually care much about the details of what we decide; I just > want us to be consistent between QEMU and kvmtool and (to the extent > that architectural differences permit) consistent between PPC and > ARM. At the moment we seem to be heading in gratuitously different > directions. My point is: is there any good technical reason for deciding not to support guest user space access, other than religious matters about the latest incarnation of The Holy Virtio Spec? Thanks, M. -- Jazz is not dead. It just smells funny. -- 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
