On Mon, Oct 09, 2017 at 03:40:02PM +0200, Paolo Bonzini wrote: > 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 <ehabk...@redhat.com> > > --- > > 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 > > > > +@node System requirements > > +@chapter System requirements > > + > > +@section 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?
I intentionally tried to not make any commitment to what should happen if running an older kernel. But a quick explanation of what can happen is probably a good idea. I will try to come up with something. -- Eduardo
