Messages in this thread | | | Date | Tue, 18 Aug 2009 19:51:21 +0300 | From | Avi Kivity <> | Subject | Re: [Alacrityvm-devel] [PATCH v3 3/6] vbus: add a "vbus-proxy" bus model for vbus_driver objects |
| |
On 08/18/2009 06:53 PM, Ira W. Snyder wrote: > So, in my system, copy_(to|from)_user() is completely wrong. There is no > userspace, only a physical system. In fact, because normal x86 computers > do not have DMA controllers, the host system doesn't actually handle any > data transfer! >
In fact, modern x86s do have dma engines these days (google for Intel I/OAT), and one of our plans for vhost-net is to allow their use for packets above a certain size. So a patch allowing vhost-net to optionally use a dma engine is a good thing.
> I used virtio-net in both the guest and host systems in my example > virtio-over-PCI patch, and succeeded in getting them to communicate. > However, the lack of any setup interface means that the devices must be > hardcoded into both drivers, when the decision could be up to userspace. > I think this is a problem that vbus could solve. >
Exposing a knob to userspace is not an insurmountable problem; vhost-net already allows changing the memory layout, for example.
-- error compiling committee.c: too many arguments to function
| |