From: "Michael S. Tsirkin" <mst@redhat.com>
To: Sridhar Samudrala <samudrala.sridhar@gmail.com>
Cc: netdev <netdev@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
avi@redhat.com, gleb@redhat.com
Subject: Re: Unable to create more than 1 guest virtio-net device using vhost-net backend
Date: Sun, 21 Mar 2010 11:55:44 +0200 [thread overview]
Message-ID: <20100321095544.GA6443@redhat.com> (raw)
In-Reply-To: <1269037167.5127.12.camel@w-sridhar.beaverton.ibm.com>
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.
--
MST
next prev parent reply other threads:[~2010-03-21 9:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-19 22:19 Unable to create more than 1 guest virtio-net device using vhost-net backend Sridhar Samudrala
2010-03-21 9:55 ` Michael S. Tsirkin [this message]
2010-03-21 10:11 ` Avi Kivity
2010-03-21 10:15 ` Michael S. Tsirkin
2010-03-21 10:29 ` Avi Kivity
2010-03-21 11:34 ` Michael S. Tsirkin
2010-03-21 11:58 ` Avi Kivity
2010-03-22 18:16 ` Michael S. Tsirkin
2010-03-22 23:41 ` Sridhar Samudrala
2010-03-21 10:21 ` Gleb Natapov
2010-03-21 10:31 ` Avi Kivity
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