On Tue, Feb 18, 2014 at 04:02:18PM +0100, Alexander Graf wrote: > On 02/18/2014 04:03 PM, Michael S. Tsirkin wrote: > >On Tue, Feb 18, 2014 at 03:48:38PM +0100, Alexander Graf wrote: > >>On 02/18/2014 01:38 PM, Greg Kurz wrote: > >>>From: Rusty Russell <ru...@rustcorp.com.au> > >>> > >>>virtio data structures are defined as "target endian", which assumes > >>>that's a fixed value. In fact, that actually means it's > >>>platform-specific. > >>> > >>>The OASIS virtio 1.0 spec will fix this. Meanwhile, create a hook for > >>>little endian ppc (and potentially ARM). This is called at device > >>>reset time (which is done before any driver is loaded) since it > >>>may involve a system call to get the status when running under kvm. > >>> > >>>[ fixed checkpatch.pl error with the virtio_byteswap initialisation, > >>> ldq_phys() API change, Greg Kurz <gk...@linux.vnet.ibm.com> ] > >>>Signed-off-by: Rusty Russell <ru...@rustcorp.com.au> > >>>Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com> > >>>--- > >>> hw/virtio/virtio.c | 6 ++ > >>> include/hw/virtio/virtio-access.h | 132 > >>> +++++++++++++++++++++++++++++++++++++ > >>> include/hw/virtio/virtio.h | 2 + > >>> stubs/Makefile.objs | 1 > >>> stubs/virtio_get_byteswap.c | 6 ++ > >>> 5 files changed, 147 insertions(+) > >>> create mode 100644 include/hw/virtio/virtio-access.h > >>> create mode 100644 stubs/virtio_get_byteswap.c > >>> > >>>diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > >>>index aeabf3a..4fd6ac2 100644 > >>>--- a/hw/virtio/virtio.c > >>>+++ b/hw/virtio/virtio.c > >>>@@ -19,6 +19,9 @@ > >>> #include "hw/virtio/virtio.h" > >>> #include "qemu/atomic.h" > >>> #include "hw/virtio/virtio-bus.h" > >>>+#include "hw/virtio/virtio-access.h" > >>>+ > >>>+bool virtio_byteswap; > >>Could this be a virtio object property rather than a global? Imagine > >>an AMP guest system with a BE and an LE system running in parallel > >>accessing two separate virtio devices. With a single global that > >>would break. > >> > >> > >>Alex > >Well, how does a device know which CPU uses it? > >I suspect we are better off waiting for 1.0 with this one. > > Good point. It just feels like a heavy layering violation to have a > global variable for all virtio devices. What if we start mixing > legacy and 1.0 devices? We could reuse the same flag, but it would > be initialized differently per device. > > > Alex
1.0 won't use the flag, it's all LE.
