On 20.10.14 08:58, Michael S. Tsirkin wrote: > Current support for bus master (clearing OK bit) together with the need to > support guests which do not enable PCI bus mastering, leads to extra state in > VIRTIO_PCI_FLAG_BUS_MASTER_BUG bit, which isn't robust in case of > cross-version > migration for the case when guests use the device before setting DRIVER_OK. > > Rip out this code, and replace it: > - Modern QEMU doesn't need VIRTIO_PCI_FLAG_BUS_MASTER_BUG > so just drop it for latest machine type. > - For compat machine types, set PCI_COMMAND if DRIVER_OK > is set. > > As this is needed for 2.1 for both pc and ppc, move PC_COMPAT macros from pc.h > to a new common header. > > Reviewed-by: Greg Kurz <gk...@linux.vnet.ibm.com> > Tested-by: Greg Kurz <gk...@linux.vnet.ibm.com> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > > Alexander, could you pls ack me merging this? > Thanks!
Have you tried whether this works with old kernel versions? We introduced the broken flag for very specific old kernel versions that got their flags wrong IIRC. Alex