should vm_bind take an array of binds?

I was contemplating future nouveau uapi and looked at the vulkan sparse binding api, and it made me wonder if the xe VM_BIND should take something like

{ vm_id; num_in_syncs; in_syncs_ptr num_binds; ptr to an array of binds num_out_syncs; out_syncs_ptr; }

So that the vulkan API could be represented with a single ioctl that batches up a bunch of operations on a single vm with a single set of in/out fences for all the binds. @mbrost and I had a quick chat on irc, and it should be possible, just wondering whether it is a good plan up-front.

@jekstrand @danvet for comment!