On Mon, Jun 22, 2009 at 11:45:00AM -0400, Gregory Haskins wrote:
Michael S. Tsirkin wrote:
It seems that a lot of complexity and trickiness with iosignalfd isHi Michael,
handling the group/item relationship, which comes about because kvm does
not currently let a device on the bus claim a write transaction based on the
value written. This could be greatly simplified if the value written
was passed to the in_range check for write operation. We could then
simply make each kvm_iosignalfd a device on the bus.
What does everyone think of the following lightly tested patch?
Its interesting, but I am not convinced its necessary. We created the
group/item layout because iosignalfds are unique in that they are
probably the only IO device that wants to do some kind of address
We actually already have aliasing: is_write flag is used for this
purpose. Actually, it's possible to remove is_write by passing
a null pointer in write_val for reads. I like this a bit less as
the code generated is less compact ... Avi, what do you think?
One is enough :)
Seriously, do you see that this saves you all of RCU, linked lists and
counters? You don't need to keep track of iofds, you don't need to
implement your own lookup logic - you just use the kvm device
and that's it.