From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755888AbaA1WUT (ORCPT ); Tue, 28 Jan 2014 17:20:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59879 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755866AbaA1WUR (ORCPT ); Tue, 28 Jan 2014 17:20:17 -0500 Date: Tue, 28 Jan 2014 20:19:01 -0200 From: Marcelo Tosatti To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, gleb@kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de Subject: Re: [PATCH 0/2] x86, kvm: fix detection of KVM features when KVM and Hyper-V coexist Message-ID: <20140128221901.GA3096@amt.cnet> References: <1390846290-26844-1-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1390846290-26844-1-git-send-email-pbonzini@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 27, 2014 at 07:11:28PM +0100, Paolo Bonzini wrote: > When KVM also presents Hyper-V features (which is useful because Windows > behaves better), Linux guests prefer KVM because emulated leaves are at > 0x40000000 and the native ones are at 0x40000100. > > However, Linux is then not accounting for the offset when reading the > available hypervisor features from CPUID. Instead of looking at > 0x40000101, it will always look at 0x40000001. > > This series makes sure that features such as async page faults or steal > time are available even if, for whatever reason, Hyper-V features are > enabled. > > As a side effect, patch 1 makes a bunch of code non inline, which also > makes sense since it should only be called during initialization. As > a result, vmlinux .text size decreases by 96 bytes. > > Please review! > > Paolo Bonzini (2): > x86, kvm: cache the base of the KVM cpuid leaves > x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101 > > arch/x86/include/asm/kvm_para.h | 33 ++++++++++++--------------------- > arch/x86/kernel/kvm.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+), 21 deletions(-) > > -- > 1.8.3.1 Reviewed-by: Marcelo Tosatti