From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39825) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e1YI5-0007f6-0n for qemu-devel@nongnu.org; Mon, 09 Oct 2017 09:40:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e1YI1-0006g2-In for qemu-devel@nongnu.org; Mon, 09 Oct 2017 09:40:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52540) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e1YI1-0006fX-Cc for qemu-devel@nongnu.org; Mon, 09 Oct 2017 09:40:13 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 55DC98765E for ; Mon, 9 Oct 2017 13:40:12 +0000 (UTC) References: <20171006215244.27104-1-ehabkost@redhat.com> <20171006215244.27104-2-ehabkost@redhat.com> From: Paolo Bonzini Message-ID: Date: Mon, 9 Oct 2017 15:40:02 +0200 MIME-Version: 1.0 In-Reply-To: <20171006215244.27104-2-ehabkost@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/7] qemu-doc: Document minimum kernel version for KVM in x86_64 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost , qemu-devel@nongnu.org Cc: "Michael S. Tsirkin" , Igor Mammedov 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 > --- > 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? Paolo