From patchwork Mon Feb 21 10:33:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 12753447 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 BD2D4C43217 for ; Mon, 21 Feb 2022 11:06:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235059AbiBULHS (ORCPT ); Mon, 21 Feb 2022 06:07:18 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:36992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243173AbiBULFi (ORCPT ); Mon, 21 Feb 2022 06:05:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8673E3F8B6 for ; Mon, 21 Feb 2022 02:33:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645439616; h=from:from: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=2s850PTFKMgt+79nojpojufcF5kfxJ20TLZLutPamXM=; b=RSON4OPyBOiEzbvwjCBFUU3PRHgccGjUtQmN+d7fhOd8XCiFsOk+q2273a9aalgdhwQZBd p8nS/3/6UpBF9vgQ3VkhwPEaAi7ovQUZXHgfRiZSxFbGRhzL1ONxmgagSdW2kMUpYinmyL SBHv5EjENvvuD3bfLIXpj3JfFJXOEMw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-322-k1gX53XgNweS7itiC_n6RQ-1; Mon, 21 Feb 2022 05:33:35 -0500 X-MC-Unique: k1gX53XgNweS7itiC_n6RQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3A28F814243; Mon, 21 Feb 2022 10:33:34 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.195.190]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5AB236F9D0; Mon, 21 Feb 2022 10:33:32 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Paolo Bonzini , linux-kernel@vger.kernel.org, Maxim Levitsky , stable@vger.kernel.org, =?utf-8?b?RMSBdmlzIE1vc8SBbnM=?= Subject: [PATCH] KVM: nSVM: fix nested tsc scaling when not enabled but MSR_AMD64_TSC_RATIO set Date: Mon, 21 Feb 2022 12:33:31 +0200 Message-Id: <20220221103331.58956-1-mlevitsk@redhat.com> In-Reply-To: <0a0b61c5c071415f213a4704ebd73e65761ec1a3.camel@redhat.com> References: <0a0b61c5c071415f213a4704ebd73e65761ec1a3.camel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org For compatibility with userspace the MSR_AMD64_TSC_RATIO can be set even when the feature is not exposed to the guest, which breaks assumptions that it has the default value in this case. Fixes: 5228eb96a487 ("KVM: x86: nSVM: implement nested TSC scaling") Cc: stable@vger.kernel.org Reported-by: Dāvis Mosāns Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/nested.c | 10 ++++------ arch/x86/kvm/svm/svm.c | 5 +++-- arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 1218b5a342fc..a2e2436057dc 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -574,14 +574,12 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset( vcpu->arch.l1_tsc_offset, svm->nested.ctl.tsc_offset, - svm->tsc_ratio_msr); + svm_get_l2_tsc_multiplier(vcpu)); svm->vmcb->control.tsc_offset = vcpu->arch.tsc_offset; - if (svm->tsc_ratio_msr != kvm_default_tsc_scaling_ratio) { - WARN_ON(!svm->tsc_scaling_enabled); + if (svm_get_l2_tsc_multiplier(vcpu) != kvm_default_tsc_scaling_ratio) nested_svm_update_tsc_ratio_msr(vcpu); - } svm->vmcb->control.int_ctl = (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) | @@ -867,8 +865,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm) vmcb_mark_dirty(svm->vmcb, VMCB_INTERCEPTS); } - if (svm->tsc_ratio_msr != kvm_default_tsc_scaling_ratio) { - WARN_ON(!svm->tsc_scaling_enabled); + if (svm_get_l2_tsc_multiplier(vcpu) != kvm_default_tsc_scaling_ratio) { vcpu->arch.tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio; svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio); } @@ -1264,6 +1261,7 @@ void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + WARN_ON_ONCE(!svm->tsc_scaling_enabled); vcpu->arch.tsc_scaling_ratio = kvm_calc_nested_tsc_multiplier(vcpu->arch.l1_tsc_scaling_ratio, svm->tsc_ratio_msr); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 975be872cd1a..5cf6bb5bfd3e 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -911,11 +911,12 @@ static u64 svm_get_l2_tsc_offset(struct kvm_vcpu *vcpu) return svm->nested.ctl.tsc_offset; } -static u64 svm_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu) +u64 svm_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); - return svm->tsc_ratio_msr; + return svm->tsc_scaling_enabled ? svm->tsc_ratio_msr : + kvm_default_tsc_scaling_ratio; } static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 852b12aee03d..006571dd30df 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -542,6 +542,7 @@ int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr, bool has_error_code, u32 error_code); int nested_svm_exit_special(struct vcpu_svm *svm); void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu); +u64 svm_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu); void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier); void nested_copy_vmcb_control_to_cache(struct vcpu_svm *svm, struct vmcb_control_area *control);