remove attempts to hide CPU information from VM in VirtualBox

[phabricator-migrator]

Information

ID: 881
PHID: PHID-TASK-fpib4soqacp3ecuevg6o
Author: Patrick
Status at Migration Time: resolved
Priority at Migration Time: Normal

Description

Reasons:

• There’s been research showing that trying to hide CPU information in a virtualizer is futile.
• There’s been a Xen issue where hiding CPU information lead to a security issue.
• spectre / meltdown defenses may depend on easy CPU detection.

Could you help with references for these please? @HulaHoop

Comments

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HulaHoop

2018-12-03 18:07:08 UTC

There’s been research showing that trying to hide CPU information in a virtualizer is futile.

I can’t find papers to that effect. That’s based on my intuition that someone can just benchmark the CPU in a VM to figure out what model they’re running on.
With full emulation it may be possible to conceal all aspects about a CPU from the guest code at expense of performance.

The opposite however is true. It’s impossible to hide the fact someone is running under a hypervisor.

There’s been a Xen issue where hiding CPU information lead to a security issue.

Dug through their CVE database with no success. Search results are equally useless.

spectre / meltdown defenses may depend on easy CPU detection.

Daniel P. Berrangé » Blog Archive » CPU model configuration for QEMU/KVM on x86 hosts