On Sun, Mar 21, 2010 at 12:11:33PM +0200, Avi Kivity wrote: > On 03/21/2010 11:55 AM, Michael S. Tsirkin wrote: >> On Fri, Mar 19, 2010 at 03:19:27PM -0700, Sridhar Samudrala wrote: >> >>> When creating a guest with 2 virtio-net interfaces, i am running >>> into a issue causing the 2nd i/f falling back to userpace virtio >>> even when vhost is enabled. >>> >>> After some debugging, it turned out that KVM_IOEVENTFD ioctl() >>> call in qemu is failing with ENOSPC. >>> This is because of the NR_IOBUS_DEVS(6) limit in kvm_io_bus_register_dev() >>> routine in the host kernel. >>> >>> I think we need to increase this limit if we want to support multiple >>> network interfaces using vhost-net. >>> Is there an alternate solution? >>> >>> Thanks >>> Sridhar >>> >> Nothing easy that I can see. Each device needs 2 of these. Avi, Gleb, >> any objections to increasing the limit to say 16? That would give us >> 5 more devices to the limit of 6 per guest. >> > > Increase it to 200, then. OK. I think we'll also need a smarter allocator than bus->dev_count++ than we now have. Right? > Is the limit visible to userspace? If not, we need to expose it. I don't think it's visible: it seems to be used in a single place in kvm. Let's add an ioctl? Note that qemu doesn't need it now ... > -- > error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
