From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: Unable to create more than 1 guest virtio-net device using vhost-net backend Date: Sun, 21 Mar 2010 13:34:43 +0200 Message-ID: <20100321113443.GB12339@redhat.com> References: <1269037167.5127.12.camel@w-sridhar.beaverton.ibm.com> <20100321095544.GA6443@redhat.com> <4BA5F0D5.6020801@redhat.com> <20100321101527.GH6443@redhat.com> <4BA5F50B.8080302@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sridhar Samudrala , netdev , "kvm@vger.kernel.org" , gleb@redhat.com To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43794 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752023Ab0CULiL (ORCPT ); Sun, 21 Mar 2010 07:38:11 -0400 Content-Disposition: inline In-Reply-To: <4BA5F50B.8080302@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, Mar 21, 2010 at 12:29:31PM +0200, Avi Kivity wrote: > On 03/21/2010 12:15 PM, Michael S. Tsirkin wrote: >>>> 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? >> > > No, why? We'll run into problems if devices are created/removed in random order, won't we? > Eventually we'll want faster scanning than the linear search we employ > now, though. Yes I suspect with 200 entries we will :). Let's just make it 16 for now? >>> 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 ... >> > > We usually expose limits via KVM_CHECK_EXTENSION(KVM_CAP_BLAH). We can > expose it via KVM_CAP_IOEVENTFD (and need to reserve iodev entries for > those). > > -- > error compiling committee.c: too many arguments to function