Here is the next iteration:

Changes from V5:
- Remove unused code for mutexes
- Remove explicit hardware memory barriers. If the host uses non-temporal
  memory operations like movnti, it will hopefully issue the memory
  barriers, too. The cheaper compiler memory barriers are still provided
  by bus_dmamap_sync().
- block: Fix error handling broken in v5 (the crash reported by johnw)
- net: set watermark for MCLGETI
- net: define constants for the queue numbers
- net: fix handling of tx queue full situations (this hopefully fixes
  the scp stall observed by johnw)

Thanks for all comments and testing.
Merge remote-tracking branch 'origin/stefan_fritsch.virtio' into stefan_fritsch.virtio

Conflicts:
	arch/amd64/conf/GENERIC
	arch/i386/conf/GENERIC
	dev/pci/files.pci
	dev/pci/if_vio.c
	dev/pci/vioblk.c
	dev/pci/virtio.c
backout/import what was actually commited
Merge branch 'stefan_fritsch.virtio' into all2

Conflicts:
	dev/usb/usbdevs.h
	dev/usb/usbdevs_data.h
keep sylvestres branch clean
tweaks as submitted
Merge branch 'all2' of ssh://afs1.freedaemon.com/afs/freedaemon.com/code/OpenBSD/git/src/sys into all2

Conflicts:
	arch/amd64/conf/GENERIC
	arch/i386/conf/GENERIC
	dev/pci/files.pci
	dev/pci/if_vio.c
	dev/pci/vioblk.c
	dev/pci/vioblkreg.h
	dev/pci/virtio.c
	dev/pci/virtio_pci.c
	dev/pci/virtioreg.h
	dev/pci/virtiovar.h
sync
Merge remote-tracking branch 'origin/master' into all2
for those who want virtual consoles with kms
Merge branch 'kettenis.vcons' into all2
sync
sync
sync
sync
sync
Merge branch 'master' into bits
Merge branch 'master' into blambert.pipe-lock-fix

Conflicts:
	sys/pipe.h
sync
sync