From: Gleb Natapov <gleb@redhat.com>
To: Alok Kataria <akataria@vmware.com>
Cc: Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Jeremy Fitzhardinge <jeremy@goop.org>,
avi@redhat.com, Rusty Russell <rusty@rustcorp.com.au>,
Zachary Amsden <zach@vmware.com>, Dan Hecht <dhecht@vmware.com>,
Jun.Nakajima@Intel.Com
Subject: Re: Use CPUID to communicate with the hypervisor.
Date: Mon, 29 Sep 2008 09:55:57 +0300 [thread overview]
Message-ID: <20080929065557.GB9952@redhat.com> (raw)
In-Reply-To: <1222472815.29886.43.camel@alok-dev1>
On Fri, Sep 26, 2008 at 04:46:55PM -0700, Alok Kataria wrote:
> 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.
next prev parent reply other threads:[~2008-09-29 6:56 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-26 23:46 Use CPUID to communicate with the hypervisor Alok Kataria
2008-09-27 0:09 ` H. Peter Anvin
2008-09-27 0:30 ` Alok Kataria
2008-09-27 0:32 ` H. Peter Anvin
2008-09-27 0:59 ` Nakajima, Jun
2008-09-27 1:55 ` H. Peter Anvin
2008-09-27 4:52 ` Nakajima, Jun
2008-09-29 20:56 ` Karel Zak
2008-09-27 1:02 ` Jeremy Fitzhardinge
2008-09-27 1:28 ` H. Peter Anvin
2008-09-27 3:11 ` Alok Kataria
2008-09-27 4:20 ` H. Peter Anvin
2008-09-27 5:37 ` Alok Kataria
2008-09-28 5:01 ` Jeremy Fitzhardinge
2008-09-29 9:28 ` Tim Deegan
2008-09-29 9:44 ` Avi Kivity
2008-09-29 6:55 ` Gleb Natapov [this message]
2008-09-29 7:37 ` Avi Kivity
2008-09-29 9:08 ` Bernd Eckenfels
2008-09-29 9:33 ` Gleb Natapov
2008-09-29 15:32 ` Nakajima, Jun
2008-09-30 9:16 ` Avi Kivity
2008-09-29 8:24 ` Gerd Hoffmann
2008-09-29 17:55 ` Alok Kataria
2008-09-29 17:58 ` H. Peter Anvin
2008-09-29 18:46 ` Gerd Hoffmann
2008-09-29 19:38 ` Alok Kataria
2008-09-29 20:31 ` H. Peter Anvin
2008-09-29 20:55 ` Nakajima, Jun
2008-09-29 21:07 ` H. Peter Anvin
2008-09-29 21:28 ` Jeremy Fitzhardinge
2008-09-29 21:49 ` H. Peter Anvin
2008-09-29 23:20 ` Zachary Amsden
2008-09-30 0:33 ` H. Peter Anvin
2008-09-30 0:12 ` Alok Kataria
2008-09-30 0:31 ` H. Peter Anvin
2008-09-30 0:56 ` Nakajima, Jun
2008-09-30 0:58 ` H. Peter Anvin
2008-09-30 1:14 ` Nakajima, Jun
2008-09-30 2:21 ` H. Peter Anvin
2008-09-30 3:14 ` Nakajima, Jun
2008-09-30 3:48 ` H. Peter Anvin
2008-09-29 22:46 ` Gerd Hoffmann
2008-09-30 0:33 ` Alok Kataria
2008-09-30 8:11 ` Gerd Hoffmann
2008-09-30 16:42 ` Zachary Amsden
2008-10-02 11:52 ` Avi Kivity
2008-10-01 4:35 ` [Hypervisors] TSC frequency change Alok Kataria
2008-10-01 9:47 ` Gerd Hoffmann
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