From patchwork Mon Oct 11 14:36:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 12550137 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25646C433EF for ; Mon, 11 Oct 2021 14:37:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B81560EE7 for ; Mon, 11 Oct 2021 14:37:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240366AbhJKOjN (ORCPT ); Mon, 11 Oct 2021 10:39:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31388 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239917AbhJKOjM (ORCPT ); Mon, 11 Oct 2021 10:39:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633963031; 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; bh=Ee9wJ57bxmWsc4scf9sZAWrwuLxZ6TkutMxSqOnUB5M=; b=So4mGKwvwyCWVtXaZE0yQfUG5WC7pNSPS2XI4Js+ysp6wGru1m4UIUdMmHzp1N7HXIVqhe sVoK50ccHNguwQWPqfiCXeooZsdSPMpHzc8A2XlPFeauxaCWH5oCXmooY+4KVlbRKKCOk6 g+SkP5rsBN4G9yGWqN2QoPHgHbUuhYE= 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-530-5tbKOs-lNv2HFe_DcF2vow-1; Mon, 11 Oct 2021 10:37:08 -0400 X-MC-Unique: 5tbKOs-lNv2HFe_DcF2vow-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B4CE9100D681; Mon, 11 Oct 2021 14:37:06 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7501F19D9B; Mon, 11 Oct 2021 14:37:04 +0000 (UTC) From: Emanuele Giuseppe Esposito To: kvm@vger.kernel.org Cc: Paolo Bonzini , Maxim Levitsky , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org, Emanuele Giuseppe Esposito Subject: [PATCH v3 0/8] KVM: nSVM: avoid TOC/TOU race when checking vmcb12 Date: Mon, 11 Oct 2021 10:36:54 -0400 Message-Id: <20211011143702.1786568-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently there is a TOC/TOU race between the check of vmcb12's efer, cr0 and cr4 registers and the later save of their values in svm_set_*, because the guest could modify the values in the meanwhile. To solve this issue, this series introduces and uses svm->nested.save structure in enter_svm_guest_mode to save the current value of efer, cr0 and cr4 and later use these to set the vcpu->arch.* state. Similarly, svm->nested.ctl contains fields that are not used, so having a full vmcb_control_area means passing uninitialized fields. Patches 1,3 and 8 take care of renaming and refactoring code. Patches 2 and 6 introduce respectively vmcb_ctrl_area_cached and vmcb_save_area_cached. Patches 4 and 5 use vmcb_save_area_cached to avoid TOC/TOU, and patch 7 uses vmcb_ctrl_area_cached. Signed-off-by: Emanuele Giuseppe Esposito --- v3: * merge this series with "KVM: nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in nested state" * rename "nested_load_save_from_vmcb12" in "nested_copy_vmcb_save_to_cache" * rename "nested_load_control_from_vmcb12" in "nested_copy_vmcb_control_to_cache" * change check functions (nested_vmcb_valid_sregs and nested_vmcb_valid_sregs) to accept only the vcpu parameter, since we only check nested state now * rename "vmcb_is_intercept_cached" in "vmcb12_is_intercept" and duplicate the implementation instead of calling vmcb_is_intercept v2: * svm->nested.save is a separate struct vmcb_save_area_cached, and not vmcb_save_area. * update also vmcb02->cr3 with svm->nested.save.cr3 RFC: * use svm->nested.save instead of local variables. * not dependent anymore from "KVM: nSVM: remove useless kvm_clear_*_queue" * simplified patches, we just use the struct and not move the check nearer to the TOU. Emanuele Giuseppe Esposito (8): KVM: nSVM: move nested_vmcb_check_cr3_cr4 logic in nested_vmcb_valid_sregs nSVM: introduce smv->nested.save to cache save area fields nSVM: rename nested_load_control_from_vmcb12 in nested_copy_vmcb_control_to_cache nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs() nSVM: use svm->nested.save to load vmcb12 registers and avoid TOC/TOU races nSVM: introduce struct vmcb_ctrl_area_cached nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in struct svm_nested_state nSVM: remove unnecessary parameter in nested_vmcb_check_controls arch/x86/kvm/svm/nested.c | 235 ++++++++++++++++++++++---------------- arch/x86/kvm/svm/svm.c | 7 +- arch/x86/kvm/svm/svm.h | 57 ++++++++- 3 files changed, 192 insertions(+), 107 deletions(-)