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Nested paging exposed to the guest
Posted: 24. Sep 2019, 22:01
by mhanor
Is it possible to expose Nested Paging (EPT/NPT) to the guest?
Re: Nested paging exposed to the guest
Posted: 24. Sep 2019, 23:24
by socratis
"EPT" as in "Ept - Extended Page Tables"? If so, everything I've seen so far
[1] has the following entry in the VBox.log:
00:00:02.439949 Nested hardware virtualization - VMX features
00:00:02.439949 Mnemonic - Description = guest (host)
...
00:00:02.439978 Ept - Extended Page Tables = 0 (1)
I have yet to see a "1 (1)" case, which means no, not at the moment at least...
[1]: I've been collecting an assortment of CPUs
(since 6.1.0b1 came out) trying to see what capabilities each one has, and see if they're nested-virtualization capable.
Re: Nested paging exposed to the guest
Posted: 25. Sep 2019, 14:01
by Technologov
I think EPT/NPT is necessary requirement for some hypervisors, including Hyper-V.
Re: Nested paging exposed to the guest
Posted: 25. Sep 2019, 14:07
by mhanor
Correct, that's why I'm asking.
Re: Nested paging exposed to the guest
Posted: 25. Sep 2019, 17:38
by socratis
Seems to me that someone(s) want to run Hyper-V inside a VM...
As previously stated in these 6.1.0b1 forums, it's best if you stick on getting "VirtualBox on VirtualBox" running first, and then the other "exotic" (as I call them) scenarios will follow. When you start seeing:
socratis wrote:00:00:02.439978 Ept - Extended Page Tables = 1 (1)
in your logs, then you'll know that something
might be ready for public testing...
Re: Nested paging exposed to the guest
Posted: 25. Sep 2019, 18:02
by mhanor
I'm only looking for a straight answer from a developer, so we can be sure. In the past, I know that you could enable some CPU features or instructions, that weren't enabled by default for the guest.
Re: Nested paging exposed to the guest
Posted: 25. Sep 2019, 18:41
by socratis
mhanor wrote:I'm only looking for a straight answer from a developer, so we can be sure
Most of the times, I
do seek confirmation before posting an answer, that's how my posts get... "gravitas"!
[quote]
socratis: EPT/NPT is not something that's passed to the guest, right?
Developer: not yet.[/quote]
For more details, join the IRC [url=irc://irc.freenode.net/vbox-dev]#vbox-dev[/url] channel...