On 09/15/2009 04:50 PM, Gregory Haskins wrote: >> Why? vhost will call get_user_pages() or copy_*_user() which ought to >> do the right thing. >> > I was speaking generally, not specifically to Ira's architecture. What > I mean is that vbus was designed to work without assuming that the > memory is pageable. There are environments in which the host is not > capable of mapping hvas/*page, but the memctx->copy_to/copy_from > paradigm could still work (think rdma, for instance). >
Sure, vbus is more flexible here. >>> As an aside: a bigger issue is that, iiuc, Ira wants more than a single >>> ethernet channel in his design (multiple ethernets, consoles, etc). A >>> vhost solution in this environment is incomplete. >>> >>> >> Why? Instantiate as many vhost-nets as needed. >> > a) what about non-ethernets? > There's virtio-console, virtio-blk etc. None of these have kernel-mode servers, but these could be implemented if/when needed. > b) what do you suppose this protocol to aggregate the connections would > look like? (hint: this is what a vbus-connector does). > You mean multilink? You expose the device as a multiqueue. > c) how do you manage the configuration, especially on a per-board basis? > pci (for kvm/x86). > Actually I have patches queued to allow vbus to be managed via ioctls as > well, per your feedback (and it solves the permissions/lifetime > critisims in alacrityvm-v0.1). > That will make qemu integration easier. >> The only difference is the implementation. vhost-net >> leaves much more to userspace, that's the main difference. >> > Also, > > *) vhost is virtio-net specific, whereas vbus is a more generic device > model where thing like virtio-net or venet ride on top. > I think vhost-net is separated into vhost and vhost-net. > *) vhost is only designed to work with environments that look very > similar to a KVM guest (slot/hva translatable). vbus can bridge various > environments by abstracting the key components (such as memory access). > Yes. virtio is really virtualization oriented. > *) vhost requires an active userspace management daemon, whereas vbus > can be driven by transient components, like scripts (ala udev) > vhost by design leaves configuration and handshaking to userspace. I see it as an advantage. -- error compiling committee.c: too many arguments to function _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
