It is confusing, for sure. As far as I understand, virtio is more or less paravirtualization (guest OS modification to talk to the host and provide device emulation via API), but requires the host hardware to have support (VT-x or what have you) in order to function. I'm not clear on those details as to why. The Xen kernel apparently doesn't, and I assumed it was then just falling back to full virtualization, but perhaps not.
I'll be at Hosting Con at the end of June, and may not be able to swing the cloudstack conference, but I'll take you up on that the next chance I get. On Thu, May 2, 2013 at 3:38 PM, Kelcey Damage (BT) < kel...@backbonetechnology.com> wrote: > Lol, > > We are just using different terms, haha. I call Hardware assisted > virtualization HAV, and separate it from paravirtualization(software > wrapper). That's where the confusion is. I agree with what you're saying, > Just not used to people referring to tier 2 HAV as paravirtualization > support. > > I build my dev cloud with full KVM_intel for the nested HV on workstation. > > But I am not using just vmx, I am also using pDMA/vt-x2/d so there is more > funky passthrough happening including pci control/north-bridge. > > On the other hand you did get me to re-read the paravirt wiki :). > > If I see you at CCC I'll buy you a beer! > > -kelcey > > > >-----Original Message----- > >From: Marcus Sorensen [mailto:shadow...@gmail.com] > >Sent: Thursday, May 02, 2013 2:32 PM > >To: dev@cloudstack.apache.org > >Subject: Re: Dev/Test Environment > > > >Libvirt is just a wrapper that controls the hypervisor. With KVM hosts, > we > look > >for the kvm_intel or kvm_amd modules, signifying that there's hardware > >support for paravirtualization. We don't see it in virtualbox, because it > doesn't > >support nested paravirtualization (It's the vmx flag that you see in > >/proc/cpuinfo, missing in virtualbox guests but not in fusion or KVM > guests). > >KVM and fusion do support it, hence we can run devcloud there. > > > >Xen devcloud doesn't require the vmx flag to be present on the cpu, so we > can > >run it in virtualbox. > > > > > >On Thu, May 2, 2013 at 2:41 PM, kel...@backbonetechnology.com < > >kel...@backbonetechnology.com> wrote: > > > >> Hate to be that guy, but it's the other way around.. Xen does provide > >> paravirtualization, KVM does not, but libvirt does with Qemu. > >> > >> Virtualbox is PV only not HAV > >> > >> http://en.m.wikipedia.org/wiki/Paravirtualization > >> > >> :) > >> > >> Sent from my HTC > >> > >> ----- Reply message ----- > >> From: "Marcus Sorensen" <shadow...@gmail.com> > >> To: "dev@cloudstack.apache.org" <dev@cloudstack.apache.org> > >> Subject: Dev/Test Environment > >> Date: Thu, May 2, 2013 1:22 PM > >> > >> Virtualbox doesn't support nested virtualization (unless they just > >> barely added it), which is why we have to use fusion (or KVM if you > >> run linux) for the KVM version of devcloud. Vbox works for the Xen > >> devcloud though because it doesn't require the Xen guests to have > >> paravirtualization, whereas cloudstack KVM guests do. > >> > >> > >> On Thu, May 2, 2013 at 2:17 PM, Joe Brockmeier <j...@zonker.net> wrote: > >> > >> > On Thu, May 2, 2013, at 03:16 PM, Joe Brockmeier wrote: > >> > > On Thu, May 2, 2013, at 01:44 PM, Soheil Eizadi wrote: > >> > > > The wiki is organized around VirtualBox, assuming it works, I > >> > > > think > >> it > >> > is > >> > > > a better choice than Fusion since it free and easy to setup. I > >> > > > don't > >> > have > >> > > > much experience with VirtualBox, does it not support nested > >> > hypervisors? > >> > > > >> > > If you've gotten something working in Fusion, it would be worth > >> > > putting that on the wiki for folks who aren't a fan of VirtualBox. > >> > > (Or folks > >> who > >> > > already use Fusion and don't want to run two desktop virt. > >> > > products...) > >> > > >> > Didn't complete my thought - would be worth putting on the wiki *on > >> > a new page* so that it's not conflicting with the "standard" > >> > DevCloud info. > >> > > >> > Best, > >> > > >> > jzb > >> > -- > >> > Joe Brockmeier > >> > j...@zonker.net > >> > Twitter: @jzb > >> > http://www.dissociatedpress.net/ > >> > > >> > >
