tree 841d0b0bcd8a5f72f8d8bdc455672d9a6e7468ca
parent 20f77f5654042cf484d8964b618faf9d620f639b
author Rusty Russell <rusty@rustcorp.com.au> 1244866595 -0600
committer Rusty Russell <rusty@rustcorp.com.au> 1244810795 +0930

virtio: meet virtio spec by finalizing features before using device

Virtio devices are supposed to negotiate features before they start using
the device, but the current code doesn't do this.  This is because the
driver's probe() function invariably has to add buffers to a virtqueue,
or probe the disk (virtio_blk).

This currently doesn't matter since no existing backend is strict about
the feature negotiation.  But it's possible to imagine a future feature
which completely changes how a device operates: in this case, we'd need
to acknowledge it before using the device.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>