Re: [RFC/PATCH 14/15] guest: detect when running on kvm

Randy Dunlap
2008-03-20T17:16:02Z

On Thu, 20 Mar 2008 17:25:26 +0100 Carsten Otte wrote:

> From: Christian Borntraeger <borntraeger@de.ibm.com>
> From: Carsten Otte <cotte@de.ibm.com>
>
> This patch adds functionality to detect if the kernel runs under the KVM
> hypervisor. A macro MACHINE_IS_KVM is exported for device drivers. This
> allows drivers to skip device detection if the systems runs non-virtualized.
> We also define a preferred console to avoid having the ttyS0, which is a line
> mode only console.
>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Signed-off-by: Carsten Otte <cotte@de.ibm.com>
> ---
> arch/s390/Kconfig | 7 +++++++
> arch/s390/kernel/early.c | 4 ++++
> arch/s390/kernel/setup.c | 10 +++++++---
> include/asm-s390/setup.h | 1 +
> 4 files changed, 19 insertions(+), 3 deletions(-)
>
> Index: kvm/arch/s390/kernel/early.c
> ===================================================================
> --- kvm.orig/arch/s390/kernel/early.c
> +++ kvm/arch/s390/kernel/early.c
> @@ -143,6 +143,10 @@ static noinline __init void detect_machi
> /* Running on a P/390 ? */
> if (cpuinfo->cpu_id.machine == 0x7490)
> machine_flags |= 4;
> +
> + /* Running under KVM ? */
> + if (cpuinfo->cpu_id.version == 0xfe)

Hi,

Where are these magic numbers documented? (0x7490, 0xfe, etc.)

> + machine_flags |= 64;
> }
>
> #ifdef CONFIG_64BIT

---
~Randy