Re: [Qemu-devel] [PATCH 1/7] qemu-doc: Document minimum kernel version for KVM in x86_64

[Paolo Bonzini]

On 06/10/2017 23:52, Eduardo Habkost wrote:
> The default set of KVM CPU features require the host kernel to
> support them.  KVM_PV_EOI is the newest one, and was included on
> Linux v3.6 (Linux commit ae7a2a3f).
> 
> Running on an old host might break management software
> expectations because the latest machine-type won't be runnable
> while older machine-types might be runnable.  Document v3.6 as
> the minimum kernel version for KVM on x86_64.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
>  qemu-doc.texi | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/qemu-doc.texi b/qemu-doc.texi
> index ecd186a159..be45b6b6f6 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi
> @@ -37,6 +37,7 @@
>  * QEMU System emulator for non PC targets::
>  * QEMU Guest Agent::
>  * QEMU User space emulator::
> +* System requirements::
>  * Implementation notes::
>  * Deprecated features::
>  * License::
> @@ -2348,6 +2349,14 @@ Act as if the host page size was 'pagesize' bytes
>  Run the emulation in single step mode.
>  @end table
>  
> address@hidden System requirements
> address@hidden System requirements
> +
> address@hidden KVM kernel module
> +
> +On x86_64 hosts, the default set of CPU features enabled by the KVM 
> accelerator
> +require the host to be running Linux v3.6 or newer.
> +
>  
>  @include qemu-tech.texi
>  
> 

Maybe we should expand on the consequences of running on older versions?

Paolo