From patchwork Tue Oct 25 12:47:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 619070 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 1898CC04A95 for ; Tue, 25 Oct 2022 12:53:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229904AbiJYMxE (ORCPT ); Tue, 25 Oct 2022 08:53:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232484AbiJYMwC (ORCPT ); Tue, 25 Oct 2022 08:52:02 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B760A11C3F for ; Tue, 25 Oct 2022 05:49:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666702160; 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=mCA4Do0tiMgEdMpQsmntRao/qg+7vUX+Fj7hqfX+/kI=; b=BlbbhpccLJfeHBPLLtu+5KMxCjwDF8nJyA+4KKIlFcWbjls656jtTDYo6RSc0yUieRnWeg Hoxz1hRKjdPWDMFt3R8YH2PKphkZAhhCTgTYCKWemS8u6DrSP6ct0a0l5xW7jxHuv3oFB6 afr/Nee5kUMA2bBgsxe/cRjPXMp7PZk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-212-zqzZbjGpOrGulRdIimA3DQ-1; Tue, 25 Oct 2022 08:49:13 -0400 X-MC-Unique: zqzZbjGpOrGulRdIimA3DQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 600AD802527; Tue, 25 Oct 2022 12:49:12 +0000 (UTC) Received: from amdlaptop.tlv.redhat.com (dhcp-4-238.tlv.redhat.com [10.35.4.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0CE8640C6E13; Tue, 25 Oct 2022 12:49:08 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Thomas Gleixner , Yang Zhong , x86@kernel.org, Jim Mattson , Vitaly Kuznetsov , Paolo Bonzini , Sean Christopherson , Wanpeng Li , Shuah Khan , Guang Zeng , Joerg Roedel , Maxim Levitsky , linux-kernel@vger.kernel.org, Dave Hansen , Ingo Molnar , linux-kselftest@vger.kernel.org, Kees Cook , "H. Peter Anvin" , Wei Wang , Borislav Petkov Subject: [PATCH RESEND v4 22/23] KVM: x86: SVM: don't save SVM state to SMRAM when VM is not long mode capable Date: Tue, 25 Oct 2022 15:47:40 +0300 Message-Id: <20221025124741.228045-23-mlevitsk@redhat.com> In-Reply-To: <20221025124741.228045-1-mlevitsk@redhat.com> References: <20221025124741.228045-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When the guest CPUID doesn't have support for long mode, 32 bit SMRAM layout is used and it has no support for preserving EFER and/or SVM state. Note that this isn't relevant to running 32 bit guests on VM which is long mode capable - such VM can still run 32 bit guests in compatibility mode. Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/svm.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 3004a5ff3fbf79..d22a809d923339 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4445,6 +4445,14 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram) if (!is_guest_mode(vcpu)) return 0; + /* + * 32-bit SMRAM format doesn't preserve EFER and SVM state. Userspace is + * responsible for ensuring nested SVM and SMIs are mutually exclusive. + */ + + if (!guest_cpuid_has(vcpu, X86_FEATURE_LM)) + return 1; + smram->smram64.svm_guest_flag = 1; smram->smram64.svm_guest_vmcb_gpa = svm->nested.vmcb12_gpa;