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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 A74F1C433EF for ; Tue, 14 Sep 2021 15:49:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8890F61209 for ; Tue, 14 Sep 2021 15:49:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235299AbhINPvB (ORCPT ); Tue, 14 Sep 2021 11:51:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31074 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235067AbhINPus (ORCPT ); Tue, 14 Sep 2021 11:50:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631634570; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gx7MKOlEUlgIaYAWawWmkyIY/NqMxsny76+oulEPAjA=; b=igEeTBO23/VY8YhS+Ua6K20ItqVU/PvgmURummuyjXGjZBHgeldNByd7P6dGKm7EYQ/cCe Z0FCNWcrt81/4EKgjI0aKz1jON6Ltxby0xZtFJneTgQqBp7EehqoUHnrVf+tdirjX3GMJJ Z3ysVouc+nwc9HPNh+cfKUvkWvkqxDE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-56-8OI8-DSbNCSsPRlXLJq6Xw-1; Tue, 14 Sep 2021 11:49:29 -0400 X-MC-Unique: 8OI8-DSbNCSsPRlXLJq6Xw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D8161CC624; Tue, 14 Sep 2021 15:49:27 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 286D75C1BB; Tue, 14 Sep 2021 15:49:21 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Vitaly Kuznetsov , Paolo Bonzini , Borislav Petkov , Bandan Das , linux-kernel@vger.kernel.org (open list), Joerg Roedel , Ingo Molnar , Wei Huang , Sean Christopherson , linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST FRAMEWORK), Maxim Levitsky , "H. Peter Anvin" , Jim Mattson , Thomas Gleixner , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), Shuah Khan , Wanpeng Li Subject: [PATCH 06/14] KVM: x86: SVM: don't set VMLOAD/VMSAVE intercepts on vCPU reset Date: Tue, 14 Sep 2021 18:48:17 +0300 Message-Id: <20210914154825.104886-7-mlevitsk@redhat.com> In-Reply-To: <20210914154825.104886-1-mlevitsk@redhat.com> References: <20210914154825.104886-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org commit adc2a23734ac ("KVM: nSVM: improve SYSENTER emulation on AMD"), made init_vmcb set vmload/vmsave intercepts unconditionally, and relied on svm_vcpu_after_set_cpuid to clear them when possible. However init_vmcb is also called when the vCPU is reset, and it is not followed by another call to svm_vcpu_after_set_cpuid because the CPUID is already set. This mistake makes the VMSAVE/VMLOAD intercept to be set when it is not needed, and harms performance of the nested guest. Fixes: adc2a23734ac ("KVM: nSVM: improve SYSENTER emulation on AMD") Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/svm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 6645542df9bd..861ac9f74331 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1199,8 +1199,6 @@ static void init_vmcb(struct kvm_vcpu *vcpu) svm_set_intercept(svm, INTERCEPT_SHUTDOWN); svm_set_intercept(svm, INTERCEPT_VMRUN); svm_set_intercept(svm, INTERCEPT_VMMCALL); - svm_set_intercept(svm, INTERCEPT_VMLOAD); - svm_set_intercept(svm, INTERCEPT_VMSAVE); svm_set_intercept(svm, INTERCEPT_STGI); svm_set_intercept(svm, INTERCEPT_CLGI); svm_set_intercept(svm, INTERCEPT_SKINIT); @@ -1377,6 +1375,10 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) svm->guest_state_loaded = false; svm_switch_vmcb(svm, &svm->vmcb01); + + svm_set_intercept(svm, INTERCEPT_VMLOAD); + svm_set_intercept(svm, INTERCEPT_VMSAVE); + init_vmcb(vcpu); svm_vcpu_init_msrpm(vcpu, svm->msrpm); -- 2.26.3