From nobody Sat Feb 7 23:34:07 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 2F5D1C77B75 for ; Tue, 23 May 2023 16:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237865AbjEWQ4r (ORCPT ); Tue, 23 May 2023 12:56:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237703AbjEWQ4o (ORCPT ); Tue, 23 May 2023 12:56:44 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D49A1DD for ; Tue, 23 May 2023 09:56:41 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-55d9a9d19c9so147508877b3.1 for ; Tue, 23 May 2023 09:56:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1684861001; x=1687453001; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=wrBhXdURti5dDN8ayuXGB0ofh5Nn3n6ogjtgMB2nW2Q=; b=Ipet8D8+ByimH4J0Yup7AfjiRNANkpz/sRtQDxkHat/bahvEYoS8gmEG+5SvYC/1P5 a3Gt1GqyMyas8m2DUR8jNdOeVjEozG7mJ8b0FpV3xK4vdY2FW1zll8VQ9WTZpnx8KK96 V8o7yNyKqoUq0JvtTqDMPlC2lQ9KE7MkOAjJOnrOLDCQBJeu382hvUwjbEl0omhYc70B 0jOPclBKZDuIPzxBbVa6p5N34U0+/g81y/fBMppddz2NEvmAoAcdVx0Z3Kh+3t1AeGg2 2SVWh4JSYEaSmlvIWLVfmxpMxRMey2K0vULQYfWcdfCOlfDucPH0EzILs16hEgQojH/B tX/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684861001; x=1687453001; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wrBhXdURti5dDN8ayuXGB0ofh5Nn3n6ogjtgMB2nW2Q=; b=XrKgxl79/h9LH4JTJUt+bTQtZAMhAn1gESk8uV1ZHfL30prh0sCot/4OuJl5F7NC4I VOJMFpL5nwGWlPzW8+nsu8Zb40zjGyTHLAp1ORHibLueQyt/q292np1jVRSqCMUqgMAU QcDCjUW/Ag3crOtGQBwboCjGMuzx+UOBq7XA42aNbYvRNDrs3nl16ac0nmihA5efzxHa eXMzhu5BLl3WZHpbekER88JQDVexPND4bfUtUAq6Kg8MKJYxoPHz7llHNTwpBalntTIY ZWX9u2TF6qGxsw6d8Du+aB7mEubT6tfGLbYLZFtFX9TyqDl1aseUVZZq003WWDUcb+Zc 9xig== X-Gm-Message-State: AC+VfDzCc6e9WrwcYLKMny5cGUJC/uq6TZszU7iRWNMTGwxPAPccEih5 Kj1W8+lab0RP7s29/jIwXx5QZG8GXctJ X-Google-Smtp-Source: ACHHUZ7zZMPI75T9CkUUAEFQYaJqKd4MnmRq2fA2kMT2h5naBwye5UXY+Z4MCIilxMLOtegZ6zbRAscuAMzd X-Received: from mizhang-super.c.googlers.com ([34.105.13.176]) (user=mizhang job=sendgmr) by 2002:a81:440b:0:b0:565:2bb:6860 with SMTP id r11-20020a81440b000000b0056502bb6860mr4621180ywa.4.1684861001145; Tue, 23 May 2023 09:56:41 -0700 (PDT) Reply-To: Mingwei Zhang Date: Tue, 23 May 2023 16:56:35 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.1.698.g37aff9b760-goog Message-ID: <20230523165635.4002711-1-mizhang@google.com> Subject: [PATCH v2] KVM: SVM: Remove TSS reloading code after VMEXIT From: Mingwei Zhang To: Sean Christopherson , Paolo Bonzini Cc: "H. Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Venkatesh Srinivas , Jim Mattson , Mingwei Zhang , Michael Roth Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Remove TSS reloading code after VMEXIT since upstream KVM after [1] has already been using VMLOAD to load host segment state (including TSS). Therefore, reload_tss() becomes redundant and could have been removed in [1]. So fix it by removing remove reload_tss() and the relevant data field tss_desc in svm_cpu_data as well as its data structure definition. [1] Check the Fixes tag. Fixes: e79b91bb3c91 ("KVM: SVM: use vmsave/vmload for saving/restoring addi= tional host state") Reported-by: Venkatesh Srinivas Suggested-by: Jim Mattson Tested-by: Mingwei Zhang Signed-off-by: Mingwei Zhang --- arch/x86/kvm/svm/svm.c | 24 ------------------------ arch/x86/kvm/svm/svm.h | 1 - 2 files changed, 25 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index eb308c9994f9..cfbe00360908 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -240,15 +240,6 @@ static u8 rsm_ins_bytes[] =3D "\x0f\xaa"; =20 static unsigned long iopm_base; =20 -struct kvm_ldttss_desc { - u16 limit0; - u16 base0; - unsigned base1:8, type:5, dpl:2, p:1; - unsigned limit1:4, zero0:3, g:1, base2:8; - u32 base3; - u32 zero1; -} __attribute__((packed)); - DEFINE_PER_CPU(struct svm_cpu_data, svm_data); =20 /* @@ -584,7 +575,6 @@ static int svm_hardware_enable(void) =20 struct svm_cpu_data *sd; uint64_t efer; - struct desc_struct *gdt; int me =3D raw_smp_processor_id(); =20 rdmsrl(MSR_EFER, efer); @@ -597,9 +587,6 @@ static int svm_hardware_enable(void) sd->next_asid =3D sd->max_asid + 1; sd->min_asid =3D max_sev_asid + 1; =20 - gdt =3D get_current_gdt_rw(); - sd->tss_desc =3D (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS); - wrmsrl(MSR_EFER, efer | EFER_SVME); =20 wrmsrl(MSR_VM_HSAVE_PA, sd->save_area_pa); @@ -3453,14 +3440,6 @@ static int svm_handle_exit(struct kvm_vcpu *vcpu, fa= stpath_t exit_fastpath) return svm_invoke_exit_handler(vcpu, exit_code); } =20 -static void reload_tss(struct kvm_vcpu *vcpu) -{ - struct svm_cpu_data *sd =3D per_cpu_ptr(&svm_data, vcpu->cpu); - - sd->tss_desc->type =3D 9; /* available 32/64-bit TSS */ - load_TR_desc(); -} - static void pre_svm_run(struct kvm_vcpu *vcpu) { struct svm_cpu_data *sd =3D per_cpu_ptr(&svm_data, vcpu->cpu); @@ -4064,9 +4043,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_= vcpu *vcpu) =20 svm_vcpu_enter_exit(vcpu, spec_ctrl_intercepted); =20 - if (!sev_es_guest(vcpu->kvm)) - reload_tss(vcpu); - if (!static_cpu_has(X86_FEATURE_V_SPEC_CTRL)) x86_spec_ctrl_restore_host(svm->virt_spec_ctrl); =20 diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index f44751dd8d5d..18af7e712a5a 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -303,7 +303,6 @@ struct svm_cpu_data { u32 max_asid; u32 next_asid; u32 min_asid; - struct kvm_ldttss_desc *tss_desc; =20 struct page *save_area; unsigned long save_area_pa; base-commit: 5c291b93e5d665380dbecc6944973583f9565ee5 --=20 2.40.1.698.g37aff9b760-goog