From nobody Mon Feb 9 12:24:15 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 38820C7EE37 for ; Wed, 7 Jun 2023 00:43:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240244AbjFGAn0 (ORCPT ); Tue, 6 Jun 2023 20:43:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240083AbjFGAnV (ORCPT ); Tue, 6 Jun 2023 20:43:21 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C34DC19A1 for ; Tue, 6 Jun 2023 17:43:19 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-bb39316a68eso2472523276.0 for ; Tue, 06 Jun 2023 17:43:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686098599; x=1688690599; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=iWpx+RfSpqGCjC/645vo3rjaj4FpsSPwYJ169RAHthE=; b=pxetOLQocTqwrPnV3EV/w5idyhiG8XYmDrXsHQd2U14s8p5u2EVCgIgk+8I7dqiP93 aOmgTbqkfnkFBItWeLUE9Ow9WgnuTiUuSudnCyfK99s4mHpzPT41YEILu+uZ1ZLpste+ obA95rKvnjRhTB4EeAZMn5VWUGX/TQqhqGdwDSRbo4frz/xTu3GGfK1BVHyimWV/rUcT xhNPGlhvhL3IyT1I8eNtErpOoK1MozEEPby6B2okd253BCEY0Bsr/DBfGQLUwAGZ9ppT oB6J2x+3FOG/A80GYb6uAFqSmGu8sl8qGMxvFPDvQPdkNZFgFyBNgkuBGTxMZoSSDelM NEzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686098599; x=1688690599; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=iWpx+RfSpqGCjC/645vo3rjaj4FpsSPwYJ169RAHthE=; b=lUGbfX708beo3uw4MzG2YA6cv8Bc2nhDaSRSjTZoIpv16+dzHGeQkLfZ4OsvxSqV4C uJjyxWjJhekk5gMbj3cksrnBFjH9fcfnWXuH/RLos40dYdtbV9NokmrvaZBp8iak4Nv6 3P3ip2P8xYFzCaiMcxivJqeBVfOd1Jd8qEBp6zHMHJIsBu/vCKWQc0rh8koDFf3tgUxq JeTvrfOS3WLlUN1D24bplI0fRgEZwqDtIAF++8v8Cjo21zJNaSVdYKbt/VCeIBN6vRlA rF65u1QQPXrLF+n8Uj2n4T1G8/QGbQT9Ul/VMss5azfbyhK6cuDgSKt+ueINpZHGwyI8 NtLw== X-Gm-Message-State: AC+VfDxUQYs4TBsat2pFwQDtGf/McTolth8/KO1JUSwiXoCMOEz01jMZ dp7bxp5mJDHLvwVS8a3D2i/yHYzAchE= X-Google-Smtp-Source: ACHHUZ6WDGc6dSyAYqCWbMICZuWNSAvkeozfOxaiyprE0dooA/9MBteFyjCTI2p5nz/KcLZhnd8fMUGpMOE= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a81:a7c3:0:b0:568:ee83:d87d with SMTP id e186-20020a81a7c3000000b00568ee83d87dmr1857439ywh.5.1686098599082; Tue, 06 Jun 2023 17:43:19 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 6 Jun 2023 17:43:10 -0700 In-Reply-To: <20230607004311.1420507-1-seanjc@google.com> Mime-Version: 1.0 References: <20230607004311.1420507-1-seanjc@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230607004311.1420507-3-seanjc@google.com> Subject: [PATCH 2/2] KVM: VMX: Drop unnecessary vmx_fb_clear_ctrl_available "cache" From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Xiaoyao Li , Pawan Gupta Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Now that KVM snapshots the host's MSR_IA32_ARCH_CAPABILITIES, drop the similar snapshot/cache of whether or not KVM is allowed to manipulate ARCH_CAPABILITIES.FB_CLEAR_CTRL. The motivation for the cache was presumably to avoid the RDMSR, e.g. boot_cpu_has_bug() is quite cheap, and modifying the vCPU's MSR_IA32_ARCH_CAPABILITIES is an infrequent option and a relatively slow path. Cc: Pawan Gupta Signed-off-by: Sean Christopherson Reviewed-by: Pawan Gupta Reviewed-by: Xiaoyao Li --- arch/x86/kvm/vmx/vmx.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 42d1148f933c..17003660138a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -237,9 +237,6 @@ static const struct { #define L1D_CACHE_ORDER 4 static void *vmx_l1d_flush_pages; =20 -/* Control for disabling CPU Fill buffer clear */ -static bool __read_mostly vmx_fb_clear_ctrl_available; - static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) { struct page *page; @@ -366,14 +363,6 @@ static int vmentry_l1d_flush_get(char *s, const struct= kernel_param *kp) return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option); } =20 -static void vmx_setup_fb_clear_ctrl(void) -{ - if ((host_arch_capabilities & ARCH_CAP_FB_CLEAR_CTRL) && - !boot_cpu_has_bug(X86_BUG_MDS) && - !boot_cpu_has_bug(X86_BUG_TAA)) - vmx_fb_clear_ctrl_available =3D true; -} - static __always_inline void vmx_disable_fb_clear(struct vcpu_vmx *vmx) { u64 msr; @@ -399,7 +388,9 @@ static __always_inline void vmx_enable_fb_clear(struct = vcpu_vmx *vmx) =20 static void vmx_update_fb_clear_dis(struct kvm_vcpu *vcpu, struct vcpu_vmx= *vmx) { - vmx->disable_fb_clear =3D vmx_fb_clear_ctrl_available; + vmx->disable_fb_clear =3D (host_arch_capabilities & ARCH_CAP_FB_CLEAR_CTR= L) && + !boot_cpu_has_bug(X86_BUG_MDS) && + !boot_cpu_has_bug(X86_BUG_TAA); =20 /* * If guest will not execute VERW, there is no need to set FB_CLEAR_DIS @@ -8580,8 +8571,6 @@ static int __init vmx_init(void) if (r) goto err_l1d_flush; =20 - vmx_setup_fb_clear_ctrl(); - for_each_possible_cpu(cpu) { INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); =20 --=20 2.41.0.162.gfafddb0af9-goog