Messages in this thread | | | Date | Thu, 31 Jan 2013 07:37:44 +0000 | From | "Jan Beulich" <> | Subject | RE: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V |
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>>> On 30.01.13 at 19:12, KY Srinivasan <kys@microsoft.com> wrote: > Presumably, Hyper-V emulation is only to run enlightened Windows. The issue > with > Xen is not that it emulates Hyper-V, but this emulation is turned on while > running Linux. > That is the reason I chose to check for Xen. Would you prefer a DMI check > for the Hyper-V > platform.
I consider DMI checks to be too fragile here - in particular with the eventual passing through of host DMI attributes to guests, this sets you up for mistakes. Instead, I would envision you scanning the whole CPUID range "reserved" for virtualization (starting at 0x40000000) and see whether you get back anything other than the Hyper-V identification (much like the way xen_cpuid_base() scans for the Xen range). Of course that's under the premise that you're right in assuming Hyper-V would never emulate any other hypervisor's interface.
Jan
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