From nobody Sun Feb 8 16:03:58 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA1A2C00A5A for ; Tue, 17 Jan 2023 23:36:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230127AbjAQXgS (ORCPT ); Tue, 17 Jan 2023 18:36:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230098AbjAQXey (ORCPT ); Tue, 17 Jan 2023 18:34:54 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ACA04A1F2; Tue, 17 Jan 2023 13:25:25 -0800 (PST) Date: Tue, 17 Jan 2023 21:25:23 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1673990724; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V3jgcTNf7s2UyBnGUo23RjRODd7U3FuCEWvWPotZJA8=; b=auSdhdEtdHiWxKNXyRIhJdUsfDNyxlYP2579L2J5ic0J9rplHWzQ8d0OkZh+OfO6t00CLc N673+xsQ3RT1urfVL7utqK1ruybi+LfRVVbKp9exgcjpPhhLRjTGOa6T93dgpDnpUGyvbm UgpPmn9H/GytiFCfrMGYLuqZakpKnn7SBKBsCDc0YxxUYIvfhZlEsh9WIdLJ9I7CTignHJ wPvtBK5Hur5l9jyvyPc0dZ3GwlMBtgMqmM57D/IEOTtQnn55TjOX128qrsBJPzQuPR7otY ASkKCjat26o4/Wkce8jtIkovXXXxNxZ/mnQ/jLwQcdybqu4rGt82H5LvZt2CTQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1673990724; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V3jgcTNf7s2UyBnGUo23RjRODd7U3FuCEWvWPotZJA8=; b=gPbp3TZpQa6u2mk2rpXLXkk8+wZFLtZYOcdqwCww429pu12Y5E729wTBmHf74mb9lurm3g tG05FdIWNMayfaDA== From: "tip-bot2 for Kim Phillips" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/cpu] x86/cpu, kvm: Move X86_FEATURE_LFENCE_RDTSC Cc: Kim Phillips , "Borislav Petkov (AMD)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230116230159.1511393-4-kim.phillips@amd.com> References: <20230116230159.1511393-4-kim.phillips@amd.com> MIME-Version: 1.0 Message-ID: <167399072372.4906.6612577556062181355.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/cpu branch of tip: Commit-ID: b594d2036c8440cda5488009d93966ae8a50c3e4 Gitweb: https://git.kernel.org/tip/b594d2036c8440cda5488009d93966ae8= a50c3e4 Author: Kim Phillips AuthorDate: Mon, 16 Jan 2023 17:01:55 -06:00 Committer: Borislav Petkov (AMD) CommitterDate: Tue, 17 Jan 2023 13:00:12 +01:00 x86/cpu, kvm: Move X86_FEATURE_LFENCE_RDTSC The LFENCE_RDTSC / LFENCE always serializing feature was a scattered bit and open-coded for KVM in __do_cpuid_func(). Add it to its newly added CPUID leaf 0x80000021 EAX proper, and propagate it in kvm_set_cpu_caps() instead. Drop the bit description comments now it's more self-describing. Also, in amd_init(), don't bother setting DE_CFG[1] any more. Whilst there, switch to using the more efficient cpu_feature_enabled() instead of static_cpu_has(). Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230116230159.1511393-4-kim.phillips@amd.c= om --- arch/x86/include/asm/cpufeatures.h | 3 ++- arch/x86/kernel/cpu/amd.c | 2 +- arch/x86/kvm/cpuid.c | 9 ++++----- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpuf= eatures.h index 1b2d40a..901128e 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -97,7 +97,7 @@ #define X86_FEATURE_SYSENTER32 ( 3*32+15) /* "" sysenter in IA32 userspac= e */ #define X86_FEATURE_REP_GOOD ( 3*32+16) /* REP microcode works well */ #define X86_FEATURE_AMD_LBR_V2 ( 3*32+17) /* AMD Last Branch Record Exten= sion Version 2 */ -#define X86_FEATURE_LFENCE_RDTSC ( 3*32+18) /* "" LFENCE synchronizes RDTS= C */ +/* FREE, was #define X86_FEATURE_LFENCE_RDTSC ( 3*32+18) "" LFENCE synchr= onizes RDTSC */ #define X86_FEATURE_ACC_POWER ( 3*32+19) /* AMD Accumulated Power Mechani= sm */ #define X86_FEATURE_NOPL ( 3*32+20) /* The NOPL (0F 1F) instructions */ #define X86_FEATURE_ALWAYS ( 3*32+21) /* "" Always-present feature */ @@ -429,6 +429,7 @@ =20 /* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word = 20 */ #define X86_FEATURE_NO_NESTED_DATA_BP (20*32+ 0) /* "" No Nested Data Brea= kpoints */ +#define X86_FEATURE_LFENCE_RDTSC (20*32+ 2) /* "" LFENCE always serializin= g / synchronizes RDTSC */ =20 /* * BUG word(s) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index f769d6d..208c2ce 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -956,7 +956,7 @@ static void init_amd(struct cpuinfo_x86 *c) =20 init_amd_cacheinfo(c); =20 - if (cpu_has(c, X86_FEATURE_XMM2)) { + if (!cpu_has(c, X86_FEATURE_LFENCE_RDTSC) && cpu_has(c, X86_FEATURE_XMM2)= ) { /* * Use LFENCE for execution serialization. On families which * don't have that MSR, LFENCE is already serializing. diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 69e433e..88c9700 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -742,8 +742,10 @@ void kvm_set_cpu_caps(void) F(SME_COHERENT)); =20 kvm_cpu_cap_mask(CPUID_8000_0021_EAX, - F(NO_NESTED_DATA_BP) + F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) ); + if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC)) + kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC); =20 kvm_cpu_cap_mask(CPUID_C000_0001_EDX, F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) | @@ -1229,7 +1231,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_ar= ray *array, u32 function) cpuid_entry_override(entry, CPUID_8000_0021_EAX); /* * Pass down these bits: - * EAX 2 LAS, LFENCE always serializing * EAX 6 NSCB, Null selector clear base * * Other defined bits are for MSRs that KVM does not expose: @@ -1239,10 +1240,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_a= rray *array, u32 function) * KVM doesn't support SMM_CTL. * EAX 9 SMM_CTL MSR is not supported */ - entry->eax &=3D BIT(2) | BIT(6); + entry->eax &=3D BIT(6); entry->eax |=3D BIT(9); - if (static_cpu_has(X86_FEATURE_LFENCE_RDTSC)) - entry->eax |=3D BIT(2); if (!static_cpu_has_bug(X86_BUG_NULL_SEG)) entry->eax |=3D BIT(6); break;