From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B7FCC64EAD for ; Sat, 29 Sep 2018 21:51:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67A512087A for ; Sat, 29 Sep 2018 21:51:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67A512087A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729228AbeI3EVo (ORCPT ); Sun, 30 Sep 2018 00:21:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52035 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728762AbeI3ESf (ORCPT ); Sun, 30 Sep 2018 00:18:35 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1g6N6E-0000HA-TR; Sat, 29 Sep 2018 22:48:31 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1g6N5w-0006rz-Dd; Sat, 29 Sep 2018 22:48:12 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David Woodhouse" , "Greg Kroah-Hartman" , "Thomas Gleixner" , "Tom Lendacky" , "Borislav Petkov" Date: Sat, 29 Sep 2018 22:43:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 039/131] x86/speculation: Add virtualized speculative store bypass disable support In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.59-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Tom Lendacky commit 11fb0683493b2da112cd64c9dada221b52463bf7 upstream. Some AMD processors only support a non-architectural means of enabling speculative store bypass disable (SSBD). To allow a simplified view of this to a guest, an architectural definition has been created through a new CPUID bit, 0x80000008_EBX[25], and a new MSR, 0xc001011f. With this, a hypervisor can virtualize the existence of this definition and provide an architectural method for using SSBD to a guest. Add the new CPUID feature, the new MSR and update the existing SSBD support to use this MSR when present. Signed-off-by: Tom Lendacky Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: - This CPUID word is feature word 11 - Adjust filenames, context] Signed-off-by: Ben Hutchings --- arch/x86/include/asm/cpufeature.h | 1 + arch/x86/include/uapi/asm/msr-index.h | 2 ++ arch/x86/kernel/cpu/bugs.c | 4 +++- arch/x86/kernel/process.c | 13 ++++++++++++- 4 files changed, 18 insertions(+), 2 deletions(-) --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -255,6 +255,7 @@ #define X86_FEATURE_AMD_IBPB (11*32+12) /* Indirect Branch Prediction Barrier */ #define X86_FEATURE_AMD_IBRS (11*32+14) /* Indirect Branch Restricted Speculation */ #define X86_FEATURE_AMD_STIBP (11*32+15) /* Single Thread Indirect Branch Predictors */ +#define X86_FEATURE_VIRT_SSBD (11*32+25) /* Virtualized Speculative Store Bypass Disable */ /* * BUG word(s) --- a/arch/x86/include/uapi/asm/msr-index.h +++ b/arch/x86/include/uapi/asm/msr-index.h @@ -225,6 +225,8 @@ #define MSR_AMD64_IBSBRTARGET 0xc001103b #define MSR_AMD64_IBS_REG_COUNT_MAX 8 /* includes MSR_AMD64_IBSBRTARGET */ +#define MSR_AMD64_VIRT_SPEC_CTRL 0xc001011f + /* Fam 16h MSRs */ #define MSR_F16H_L2I_PERF_CTL 0xc0010230 #define MSR_F16H_L2I_PERF_CTR 0xc0010231 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -266,7 +266,9 @@ static void x86_amd_ssb_disable(void) { u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_ssbd_mask; - if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD)) + if (boot_cpu_has(X86_FEATURE_VIRT_SSBD)) + wrmsrl(MSR_AMD64_VIRT_SPEC_CTRL, SPEC_CTRL_SSBD); + else if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD)) wrmsrl(MSR_AMD64_LS_CFG, msrval); } --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -326,6 +326,15 @@ static __always_inline void amd_set_core } #endif +static __always_inline void amd_set_ssb_virt_state(unsigned long tifn) +{ + /* + * SSBD has the same definition in SPEC_CTRL and VIRT_SPEC_CTRL, + * so ssbd_tif_to_spec_ctrl() just works. + */ + wrmsrl(MSR_AMD64_VIRT_SPEC_CTRL, ssbd_tif_to_spec_ctrl(tifn)); +} + static __always_inline void intel_set_ssb_state(unsigned long tifn) { u64 msr = x86_spec_ctrl_base | ssbd_tif_to_spec_ctrl(tifn); @@ -335,7 +344,9 @@ static __always_inline void intel_set_ss static __always_inline void __speculative_store_bypass_update(unsigned long tifn) { - if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) + if (static_cpu_has(X86_FEATURE_VIRT_SSBD)) + amd_set_ssb_virt_state(tifn); + else if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) amd_set_core_ssb_state(tifn); else intel_set_ssb_state(tifn);