Re: Use CPUID to communicate with the hypervisor.

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From: Gleb Natapov

Subject: Re: Use CPUID to communicate with the hypervisor.

Date: Sunday, September 28, 2008 - 11:55 pm

On Fri, Sep 26, 2008 at 04:46:55PM -0700, Alok Kataria wrote:
quoted text> From: Alok N Kataria <akataria@vmware.com>
> 
> This patch proposes to use a cpuid interface to detect if we are running on an
> hypervisor.
> The discovery of a hypervisor is determined by bit 31 of CPUID#1_ECX, which is
> defined to be "hypervisor present bit". For a VM, the bit is 1, otherwise it is
> set to 0. This bit is not officially documented by either Intel/AMD yet, but
> they plan to do so some time soon, in the meanwhile they have promised to keep
> it reserved for virtualization.
> 
> Also, Intel & AMD have reserved the cpuid levels 0x40000000 - 0x400000FF for
> software use. Hypervisors can use these levels to provide an interface to pass
> information from the hypervisor to the guest. This is similar to how we extract
> information about a physical cpu by using cpuid.
> XEN/KVM are already using the info leaf to get the hypervisor signature.
> 
Can this interface be used to pass variable sized data from a hypervisor
to a gust? ACPI or DMI tables for instance.

--
			Gleb.
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Messages in current thread:

Use CPUID to communicate with the hypervisor., Alok Kataria, (Fri Sep 26, 4:46 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Fri Sep 26, 5:09 pm)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Fri Sep 26, 5:30 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Fri Sep 26, 5:32 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Fri Sep 26, 5:59 pm)

Re: Use CPUID to communicate with the hypervisor., Jeremy Fitzhardinge, (Fri Sep 26, 6:02 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Fri Sep 26, 6:28 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Fri Sep 26, 6:55 pm)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Fri Sep 26, 8:11 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Fri Sep 26, 9:20 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Fri Sep 26, 9:52 pm)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Fri Sep 26, 10:37 pm)

Re: Use CPUID to communicate with the hypervisor., Jeremy Fitzhardinge, (Sat Sep 27, 10:01 pm)

Re: Use CPUID to communicate with the hypervisor., Gleb Natapov, (Sun Sep 28, 11:55 pm)

Re: Use CPUID to communicate with the hypervisor., Avi Kivity, (Mon Sep 29, 12:37 am)

Re: Use CPUID to communicate with the hypervisor., Gerd Hoffmann, (Mon Sep 29, 1:24 am)

Re: Use CPUID to communicate with the hypervisor., Bernd Eckenfels, (Mon Sep 29, 2:08 am)

Re: Use CPUID to communicate with the hypervisor., Tim Deegan, (Mon Sep 29, 2:28 am)

Re: Use CPUID to communicate with the hypervisor., Gleb Natapov, (Mon Sep 29, 2:33 am)

Re: Use CPUID to communicate with the hypervisor., Avi Kivity, (Mon Sep 29, 2:44 am)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Mon Sep 29, 8:32 am)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Mon Sep 29, 10:55 am)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 10:58 am)

Re: Use CPUID to communicate with the hypervisor., Gerd Hoffmann, (Mon Sep 29, 11:46 am)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Mon Sep 29, 12:38 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 1:31 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Mon Sep 29, 1:55 pm)

Re: Use CPUID to communicate with the hypervisor., Karel Zak, (Mon Sep 29, 1:56 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 2:07 pm)

Re: Use CPUID to communicate with the hypervisor., Jeremy Fitzhardinge, (Mon Sep 29, 2:28 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 2:49 pm)

Re: Use CPUID to communicate with the hypervisor., Gerd Hoffmann, (Mon Sep 29, 3:46 pm)

Re: Use CPUID to communicate with the hypervisor., Zachary Amsden, (Mon Sep 29, 4:20 pm)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Mon Sep 29, 5:12 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 5:31 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 5:33 pm)

Re: Use CPUID to communicate with the hypervisor., Alok Kataria, (Mon Sep 29, 5:33 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Mon Sep 29, 5:56 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 5:58 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Mon Sep 29, 6:14 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 7:21 pm)

RE: Use CPUID to communicate with the hypervisor., Nakajima, Jun, (Mon Sep 29, 8:14 pm)

Re: Use CPUID to communicate with the hypervisor., H. Peter Anvin, (Mon Sep 29, 8:48 pm)

Re: Use CPUID to communicate with the hypervisor., Gerd Hoffmann, (Tue Sep 30, 1:11 am)

Re: Use CPUID to communicate with the hypervisor., Avi Kivity, (Tue Sep 30, 2:16 am)

Re: Use CPUID to communicate with the hyper