From patchwork Mon Jan 7 18:20:44 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Habkost X-Patchwork-Id: 1941821 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 2282A3FC5A for ; Mon, 7 Jan 2013 18:20:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754736Ab3AGSUA (ORCPT ); Mon, 7 Jan 2013 13:20:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41334 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754643Ab3AGSTx (ORCPT ); Mon, 7 Jan 2013 13:19:53 -0500 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r07IJBd4023475 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 7 Jan 2013 13:19:11 -0500 Received: from blackpad.lan.raisama.net (vpn1-7-15.gru2.redhat.com [10.97.7.15]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r07IJ9Qv027812; Mon, 7 Jan 2013 13:19:09 -0500 Received: by blackpad.lan.raisama.net (Postfix, from userid 500) id 474B2203D27; Mon, 7 Jan 2013 16:20:50 -0200 (BRST) From: Eduardo Habkost To: qemu-devel@nongnu.org Cc: libvir-list@redhat.com, kvm@vger.kernel.org, =?UTF-8?q?Andreas=20F=C3=A4rber?= , Igor Mammedov , Gleb Natapov , "Michael S. Tsirkin" , Marcelo Tosatti , Jiri Denemark Subject: [PATCH qom-cpu 3/7] target-i386: Disable kvm_mmu by default Date: Mon, 7 Jan 2013 16:20:44 -0200 Message-Id: <1357582848-16575-4-git-send-email-ehabkost@redhat.com> In-Reply-To: <1357582848-16575-1-git-send-email-ehabkost@redhat.com> References: <1357582848-16575-1-git-send-email-ehabkost@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM_CAP_PV_MMU capability reporting was removed from the kernel since v2.6.33 (see commit a68a6a7282373), and was completely removed from the kernel since v3.3 (see commit fb92045843). It doesn't make sense to keep it enabled by default, as it would cause unnecessary hassle when using the "enforce" flag. This disables kvm_mmu on all machine-types. With this fix, the possible scenarios when migrating from QEMU <= 1.3 to QEMU 1.4 are; ------------+------------+---------------------------------------------------- src kernel | dst kernel | Result ------------+------------+---------------------------------------------------- >= 2.6.33 | any | kvm_mmu was already disabled and will stay disabled <= 2.6.32 | >= 3.3 | correct live migration is impossible <= 2.6.32 | <= 3.2 | kvm_mmu will be disabled on next guest reboot * ------------+------------+---------------------------------------------------- * If they are running kernel <= 2.6.32 and want kvm_mmu to be kept enabled on guest reboot, they can explicitly add +kvm_mmu to the QEMU command-line. Using 2.6.33 and higher, it is not possible to enable kvm_mmu explicitly anymore. Signed-off-by: Eduardo Habkost --- Cc: kvm@vger.kernel.org Cc: Michael S. Tsirkin Cc: Gleb Natapov Cc: Marcelo Tosatti Cc: libvir-list@redhat.com Cc: Jiri Denemark Changes v2: - Coding style fix - Removed redundant comments above machine init functions Changes v3: - Eliminate per-machine-type compatibility code --- target-i386/cpu.c | 1 - 1 file changed, 1 deletion(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 40400ac..b09b625 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -159,7 +159,6 @@ int enforce_cpuid = 0; #if defined(CONFIG_KVM) static uint32_t kvm_default_features = (1 << KVM_FEATURE_CLOCKSOURCE) | (1 << KVM_FEATURE_NOP_IO_DELAY) | - (1 << KVM_FEATURE_MMU_OP) | (1 << KVM_FEATURE_CLOCKSOURCE2) | (1 << KVM_FEATURE_ASYNC_PF) | (1 << KVM_FEATURE_STEAL_TIME) |