From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nadav Amit Subject: Re: requiring virtual NMI for Intel processors? Date: Mon, 20 Feb 2017 12:35:02 -0800 Message-ID: <277837C2-746F-4DBC-AF6F-C4E464831CC3@gmail.com> References: <3f272924-3878-5005-fc8c-200d808da2bb@redhat.com> Mime-Version: 1.0 (Mac OS X Mail 10.2 \(3259\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: KVM list To: Paolo Bonzini Return-path: Received: from mail-pg0-f44.google.com ([74.125.83.44]:34078 "EHLO mail-pg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570AbdBTUfJ (ORCPT ); Mon, 20 Feb 2017 15:35:09 -0500 Received: by mail-pg0-f44.google.com with SMTP id 1so5016368pgi.1 for ; Mon, 20 Feb 2017 12:35:09 -0800 (PST) In-Reply-To: <3f272924-3878-5005-fc8c-200d808da2bb@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: I have no information that suggests otherwise, but just a couple of small comments: 1. It seems you look on Xeons (excluding Yonah and Cedarmill). Desktop and laptop CPUs may have different fusing than servers. 2. No Atoms in the list. > On Feb 20, 2017, at 11:43 AM, Paolo Bonzini wrote: > > I spent some time collecting vmxcap output for various Intel processors. > I tested Prescott (Cedar Mill actually), Yonah (32-bit only) and every > microarchitecture from Conroe to Haswell. As far as I can tell, these > are all Intel processors that supported virtualization. My notes are > attached. > > The only ones without virtual NMI and NMI-window exiting were the Cedar > Mill and Yonah. One is a Pentium 4 microarchitecture that one should > use as a toaster rather than as a hypervisor; the other is not even > 64-bit capable. It also has VMCS restricted to 32 bit addresses, so if > it ever had >3.5GB memory installed KVM would break. > > Based on this, I'd like to drop the code that emulates the NMI window > and just require these two features in KVM 4.11+. > > Any objections? > > Paolo >