5 ms·
Any CPU can only have one hypervisor running at a time. Thus the recursion stops pretty quick.
by Danieru 7y ago
Any CPU can only have one hypervisor running at a time. Thus the recursion stops pretty quick.
- Nullabillity 7y agoCygwin and Wine don't use virtualization. And even if they did, most hypervisors support nesting these days.
- ape4 7y agoBecause, of course, its not a emulator
- mschuster91 7y agoWhy? There's only one hypervisor involved for the initial "wine" environment.
- lnx01 7y agoNeither WINE nor WSLv1 use virtualisation. WSLv2 does use virtualisation however; but WINE still isn't a VM.
- mschuster91 7y agoI was referring to WSLv2 here, so technically there is a hypervisor involved at the root level hosting the first WINE instance in the chain. Further recursion WINE => Cygwin => WINE however will not require more nesting of hypervisors.
- intea 7y agoActually most modern hypervisors allow nested virtualization. https://www.linux-kvm.org/page/Nested_Guests https://www.linux-kvm.org/page/Nested_Guests https://communities.vmware.com/docs/DOC-8970 https://communities.vmware.com/docs/DOC-8970
- skissane 7y agoNot even just modern hypervisors. The IBM mainframe hypervisor z/VM (and its predecessor VM/CMS) has supported nested virtualisation for decades. It was an important tool to support its own development (especially considering that mainframes were expensive and not even IBM could afford to give every mainframe OS developer a whole mainframe to themselves.)
- bartvanH 7y agoWell, yes and no. On modern enough hardware you can do nested virtualisation, so you can run kvm in esxi on hyper-v if you want. Not that it's very usefull, but it is a fun weekend project nonetheless.
- jrockway 7y agoI use nested virtualization for Windows Desktop -> Linux VM -> minikube. Works great. Obviously you could just run minikube under Windows, but then from the Linux VM you can't "minikube ssh" and whatnot, so nested virtualization makes everything a lot simpler.
- monocasa 7y agoYou can even do nested virtualization without hardware support, it's just super duper slow and not a lot of hypervisors think it's worth the complexity increase.
- saint_abroad 7y agoIntel and AMD CPUs have supported hardware-accelerated nested virtualisation for quite some time now. https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/user-guide/nested-virtualization https://docs.microsoft.com/en-us/virtualization/hyper-v-on-w... https://www.redhat.com/en/blog/inception-how-usable-are-nested-kvm-guests https://www.redhat.com/en/blog/inception-how-usable-are-nest...
- Tepix 7y agoWSL1 is not a "real" VM. https://blogs.msdn.microsoft.com/wsl/2016/05/23/pico-process-overview/ https://blogs.msdn.microsoft.com/wsl/2016/05/23/pico-process...
- aasasd 7y agoAside from all the other corrections, hardware virtualization support isn't necessary for virtualization.