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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 2A1ADC47082 for ; Wed, 26 May 2021 13:20:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 06B6B613C3 for ; Wed, 26 May 2021 13:20:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232948AbhEZNWG (ORCPT ); Wed, 26 May 2021 09:22:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:30292 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231911AbhEZNWE (ORCPT ); Wed, 26 May 2021 09:22:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622035233; 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=p9p1x7BswRsuTEvRmatlOnyjD69LSl91w/XnLyyopxg=; b=eKYJxdzffm4cdlMME1PbA/+08RAz6P3tBY9m6BV1xoG07ryAXwEH1NfBqs2TBnd0juVChQ Xo9pssxPjcwkHWXMONbvoZv4GcPfti4SBVTldMbItANyfYqljhBqxjP0irIAWgb0Xo1ds2 AdX0tUiMlaasCU4Kw+PPfqWdEGcguXg= 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-232-OaFC7kshP1qDaHOMVdhRog-1; Wed, 26 May 2021 09:20:31 -0400 X-MC-Unique: OaFC7kshP1qDaHOMVdhRog-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9F7D0501EE; Wed, 26 May 2021 13:20:30 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.195.123]) by smtp.corp.redhat.com (Postfix) with ESMTP id 10E095D9CC; Wed, 26 May 2021 13:20:27 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Maxim Levitsky , linux-kernel@vger.kernel.org Subject: [PATCH v3 00/11] KVM: nVMX: Fixes for nested state migration when eVMCS is in use Date: Wed, 26 May 2021 15:20:15 +0200 Message-Id: <20210526132026.270394-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changes since v2: - 'KVM: nVMX: Use '-1' in 'hv_evmcs_vmptr' to indicate that eVMCS is not in use'/ 'KVM: nVMX: Introduce 'EVMPTR_MAP_PENDING' post-migration state' patches instead of 'KVM: nVMX: Introduce nested_evmcs_is_used()' [Paolo] - 'KVM: nVMX: Don't set 'dirty_vmcs12' flag on enlightened VMPTRLD' patch added [Max] - 'KVM: nVMX: Release eVMCS when enlightened VMENTRY was disabled' patch added. - 'KVM: nVMX: Make copy_vmcs12_to_enlightened()/copy_enlightened_to_vmcs12() return 'void'' patch added [Paolo] - R-b tags added [Max] Original description: Commit f5c7e8425f18 ("KVM: nVMX: Always make an attempt to map eVMCS after migration") fixed the most obvious reason why Hyper-V on KVM (e.g. Win10 + WSL2) was crashing immediately after migration. It was also reported that we have more issues to fix as, while the failure rate was lowered signifincatly, it was still possible to observe crashes after several dozens of migration. Turns out, the issue arises when we manage to issue KVM_GET_NESTED_STATE right after L2->L2 VMEXIT but before L1 gets a chance to run. This state is tracked with 'need_vmcs12_to_shadow_sync' flag but the flag itself is not part of saved nested state. A few other less significant issues are fixed along the way. While there's no proof this series fixes all eVMCS related problems, Win10+WSL2 was able to survive 3333 (thanks, Max!) migrations without crashing in testing. Patches are based on the current kvm/next tree. Vitaly Kuznetsov (11): KVM: nVMX: Use '-1' in 'hv_evmcs_vmptr' to indicate that eVMCS is not in use KVM: nVMX: Don't set 'dirty_vmcs12' flag on enlightened VMPTRLD KVM: nVMX: Release eVMCS when enlightened VMENTRY was disabled KVM: nVMX: Make copy_vmcs12_to_enlightened()/copy_enlightened_to_vmcs12() return 'void' KVM: nVMX: Introduce 'EVMPTR_MAP_PENDING' post-migration state KVM: nVMX: Release enlightened VMCS on VMCLEAR KVM: nVMX: Ignore 'hv_clean_fields' data when eVMCS data is copied in vmx_get_nested_state() KVM: nVMX: Force enlightened VMCS sync from nested_vmx_failValid() KVM: nVMX: Reset eVMCS clean fields data from prepare_vmcs02() KVM: nVMX: Request to sync eVMCS from VMCS12 after migration KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never lost arch/x86/kvm/vmx/evmcs.c | 3 + arch/x86/kvm/vmx/evmcs.h | 8 + arch/x86/kvm/vmx/nested.c | 144 +++++++++++------- arch/x86/kvm/vmx/nested.h | 11 +- arch/x86/kvm/vmx/vmx.c | 1 + .../testing/selftests/kvm/x86_64/evmcs_test.c | 64 ++++---- 6 files changed, 140 insertions(+), 91 deletions(-) -- 2.31.1