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From: Sridhar Samudrala <samudrala.sridhar@gmail.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev <netdev@vger.kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Unable to create more than 1 guest virtio-net device using vhost-net backend
Date: Fri, 19 Mar 2010 15:19:27 -0700	[thread overview]
Message-ID: <1269037167.5127.12.camel@w-sridhar.beaverton.ibm.com> (raw)

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



             reply	other threads:[~2010-03-19 22:25 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-19 22:19 Sridhar Samudrala [this message]
2010-03-21  9:55 ` Unable to create more than 1 guest virtio-net device using vhost-net backend Michael S. Tsirkin
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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