Messages in this thread | | | Date | Wed, 31 Jul 2013 17:32:36 +0300 | Subject | Re: [QUERY] lguest64 | From | Mike Rapoport <> |
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On Wed, Jul 31, 2013 at 4:19 PM, H. Peter Anvin <hpa@zytor.com> wrote: > On 07/31/2013 06:07 AM, Mike Rapoport wrote: >>> >>> "We can add a pvops user and that won't change the number of pvops >>> users" What?! >> >> We modify existing pvops user, IMHO. lguest is existing pvops user and >> my idea was to extend it, rather than add lguest64 alongside lguest32. >> > > That is nothing but creative accounting, sorry.
If you count Xen PV 32 and 64 as two pvops users than indeed so :)
>>>>> Yes, the subset of x86-64 machines for which there isn't hardware >>>>> virtualization support is pretty uninteresting. >>>> >>>> There are plenty virtual machines in EC2, Rackspace, HP and other >>>> clouds that do not have hardware virtualization. I believe that >>>> running a hypervisor on them may be pretty interesting. >>> >>> The big problem with pvops is that they are a permanent tax on future >>> development -- a classic case of "the hooks problem." As such it is >>> important that there be a real, significant, use case with enough users >>> to make the pain worthwhile. With Xen looking at sunsetting PV support >>> with a long horizon, it might currently be possible to remove pvops some >>> time in the early 2020s or so timeframe. Introducing and promoting a >>> new user now would definitely make that impossible. >> >> I surely cannot predict how many users there will be for nested >> virtualization in public cloud from now till the point when public >> cloud providers will allow usage of hardware for that purpose. >> Nevertheless, I believe that nested virtualization in public clouds is >> a real use case which will have real users. > > Then that will show... however, whether or not lguest64 will be used for > that purpose is anyone's guess. I suspect personally that people will > use the already-deployed Xen PV for that purpose and it will stretch the > lifespan of that technology.
Well, nesting Xen PV in a cloud VM, even fully-virtualied, seems to me significantly more complicated than nesting an lguest.
> Now, nested PV is an even uglier case, and at least some public clouds > are using PV at the base layer.
Unfortunately, majority of public cloud VMs are PV. And, indeed, nested PV is not nice...
> -hpa > >
-- Sincerely yours, Mike.
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