From patchwork Fri Nov 9 22:21:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Mattson X-Patchwork-Id: 10676651 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3D72114BD for ; Fri, 9 Nov 2018 22:21:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2DFEE2F2C7 for ; Fri, 9 Nov 2018 22:21:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1F51F2F30D; Fri, 9 Nov 2018 22:21:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 012DF2F2C7 for ; Fri, 9 Nov 2018 22:21:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728294AbeKJIEL (ORCPT ); Sat, 10 Nov 2018 03:04:11 -0500 Received: from mail-pg1-f201.google.com ([209.85.215.201]:44469 "EHLO mail-pg1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727746AbeKJIEL (ORCPT ); Sat, 10 Nov 2018 03:04:11 -0500 Received: by mail-pg1-f201.google.com with SMTP id a2so2115260pgt.11 for ; Fri, 09 Nov 2018 14:21:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=SrUmZiRUnNW01JpxEki4FlDcS9x4xXSKKg8MtZhVpx8=; b=Da5T5f5LU1U8/7wsZRicvmkZNkoX6gJuODq6HLGxLGjAL61nSn96WB4IvM//FICDEz DsGB5iqCqauGuijw4hfmncLgsL1Bw48cEyzAo59KHtE1sbvNFZp4ofZvcBtDZ93gDQjt Tw/iPPBSS/9L1C9QvwCQBMEa5B858Qj5I6ziM+v6oMU4aG9cfdEdGuRh6U2k5P0N5+9Q DI6DYRhqUeMU2xUXBjbZSHVxEtuvmspNxg0ob2PHxel+V2EefSKdoXGgn7ISf8nfQ0kF Wry6c6E4oBr9Vzry8qEcRJtc2qiXHIqvJ7bb/b9RKT702en21mtPA/pM/Itu5ONKAllJ sA3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=SrUmZiRUnNW01JpxEki4FlDcS9x4xXSKKg8MtZhVpx8=; b=XbCk3EY8e9SuO9oo7BGNzEwhOSzK+fp9kHbf+DTiXiSvv3gb/FwZhzyvTtZY8Ua6ZY AQq8zr/PXIUvIVSua9rWaQ6FaB/q0fhIDR/mSFepcHUBKUs98vgCkDsdXzh1cpXuZkDn kL8nflwt5v6CdNS7fAJ7ecOutZ10UlQ+uGwVtAiYiOBUiSgDItSZenlO5P1LH2nAtQHd /zm/OOxwW1U7xd8BNNCikkNYMZ0xciLD3Uhxwu794JKLaL535SfsWihUc1jR5/8X3awL gxxtWJYIzD/f+royL8Guez7X+SjRY6bqqNqHDddOT/rsXLQdkLRA+M6XrgDmV5GJ+wgC olHg== X-Gm-Message-State: AGRZ1gKZkZBMR926w8hiAMcrPO/ynQ9xtNLoZzDpWQLyd2ujNXGLLJoq cKG4uuBzQg8zxs3DfkYF9pAB2ZIWq/HIsOy4/25g4yCF8+dxime8VY7Bg8ia44EiBM0v+x2HaAX S6mldMlSSco7ioWeM0leQ7QWrDWw7rqdfvyNHusnvL9TTn1XWKIs3wqs1jrkI0nI= X-Google-Smtp-Source: AJdET5dfFg9c6LGOTairD69751cuxS5l8eNN90xoABIqyf2G5LHKUyfzkxENq7dl8B8YwzeFOwkuayKgQtG9bg== X-Received: by 2002:a17:902:b08c:: with SMTP id p12-v6mr115330plr.64.1541802096001; Fri, 09 Nov 2018 14:21:36 -0800 (PST) Date: Fri, 9 Nov 2018 14:21:29 -0800 Message-Id: <20181109222131.60885-1-jmattson@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.19.1.930.g4563a0d9d0-goog Subject: [PATCH v2 2/4] kvm: vmx: Omit MSR_STAR from vmx_msr_index[] for i386 builds From: Jim Mattson To: kvm@vger.kernel.org Cc: Marc Orr , Peter Shier , Liran Alon , Jim Mattson Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The SYSCALL instruction is only supported in 64-bit mode on Intel CPUs. With VT-x, A legacy-mode hypervisor can't launch a long-mode guest. Therefore, we can omit MSR_STAR support for i386 builds. Note that the elided comment has not been relevant since move_msr_up() was introduced in commit a75beee6e4f5d ("KVM: VMX: Avoid saving and restoring msrs on lightweight vmexit"). Signed-off-by: Jim Mattson Reviewed-by: Peter Shier Reviewed-by: Marc Orr --- arch/x86/kvm/vmx.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 120fc97a63fc..da7f43457d49 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1387,15 +1387,11 @@ static u64 host_efer; static void ept_save_pdptrs(struct kvm_vcpu *vcpu); -/* - * Keep MSR_STAR at the end, as setup_msrs() will try to optimize it - * away by decrementing the array size. - */ static const u32 vmx_msr_index[] = { #ifdef CONFIG_X86_64 - MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR, + MSR_SYSCALL_MASK, MSR_STAR, MSR_LSTAR, MSR_CSTAR, #endif - MSR_EFER, MSR_TSC_AUX, MSR_STAR, + MSR_EFER, MSR_TSC_AUX }; DEFINE_STATIC_KEY_FALSE(enable_evmcs);