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=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5A164C4743C for ; Wed, 23 Jun 2021 09:39:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34A9B6113B for ; Wed, 23 Jun 2021 09:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230312AbhFWJl4 (ORCPT ); Wed, 23 Jun 2021 05:41:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43842 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230170AbhFWJly (ORCPT ); Wed, 23 Jun 2021 05:41:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624441176; 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=Nk49XlXeHosOswVGCCNxHMrFlyXg5sckW14ipg09Etw=; b=ifnvWxl5uL0qoLZTJOoQnJSsE5V4Imw8CS0baXcFr2UJ7iyBeRx7Wr7i08dINGMbBWEYps zvXy9k6sZAtNdXHmlVnxNj1BtVO6Y+kCVmiDHkSRoykgzLjMfx3thy3clhVmqGf2PxSZcv R25yy7FzJkhqyGlgU4XglqD0n9VsNE4= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-549-hsdo36C_NF-IwKg1yJ6qAQ-1; Wed, 23 Jun 2021 05:39:35 -0400 X-MC-Unique: hsdo36C_NF-IwKg1yJ6qAQ-1 Received: by mail-wr1-f71.google.com with SMTP id p2-20020a5d63820000b029011a9ecaf55dso829712wru.19 for ; Wed, 23 Jun 2021 02:39:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Nk49XlXeHosOswVGCCNxHMrFlyXg5sckW14ipg09Etw=; b=iLN3O0IN37yWEUbdugzhaEb9J3KYYmOUqMmcN7nmLhbT5x0I+LQhMoXOcNwub39lBx ovgQNCWOPj7FDAwYbY/FtyEAsT6H1IjdkbHWWbCtum/jdv8597/V/0EPEPWVLJOuNG9Y qyegvMaNbFrtP2GH3vyRsERDMYqoKi5rZukuM4otNKhKjSOafxRcmyPj0GrmYWfcNADp WA8yohp2IoQWCB4iIRtNqTN7vgyd+i35QdBiu/r2zTYWsT3dRoysHcFyQXOIh8FRqkYg icksiQDNF3evuwtV+xpPeyYg788ilUqRzOqovEI4bBiVBxDXzum8bmvnNes3NXe+n9U9 hvKQ== X-Gm-Message-State: AOAM530J59Wudd5awEH3H4mWt2guo79MQe3GIv+CcJTzqjMy0aIr4nnl 0wqL2Z7yYNBZoPXCHZwncQIlNlr1MdrVd+R9HSxgbbjC4fSZ1Gm2eenDBMq+ayarzTH2sz8Orjm EEw2TDffjiCbuxOgyEGdyGpTajAjk2OjcHJoh8as97kasP2g/kf0HqA/RZGHSJBqq6E51EKCx+/ 80 X-Received: by 2002:adf:f946:: with SMTP id q6mr10260017wrr.283.1624441173938; Wed, 23 Jun 2021 02:39:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwhIlzIfSpKT+lNu6OZDVYqOFhFkR+ZB2WuZ/Xszdb1cxSHhgpp7LV9CAMtlxzmCLxqDCiCeg== X-Received: by 2002:adf:f946:: with SMTP id q6mr10259987wrr.283.1624441173707; Wed, 23 Jun 2021 02:39:33 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id s23sm5715276wmh.5.2021.06.23.02.39.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Jun 2021 02:39:33 -0700 (PDT) To: Vitaly Kuznetsov , kvm@vger.kernel.org Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Maxim Levitsky , Cathy Avery , Emanuele Giuseppe Esposito , linux-kernel@vger.kernel.org References: <20210623074427.152266-1-vkuznets@redhat.com> From: Paolo Bonzini Subject: Re: [PATCH RFC] KVM: nSVM: Fix L1 state corruption upon return from SMM Message-ID: Date: Wed, 23 Jun 2021 11:39:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210623074427.152266-1-vkuznets@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/06/21 09:44, Vitaly Kuznetsov wrote: > - RFC: I'm not 100% sure my 'smart' idea to use currently-unused HSAVE area > is that smart. Also, we don't even seem to check that L1 set it up upon > nested VMRUN so hypervisors which don't do that may remain broken. A very > much needed selftest is also missing. It's certainly a bit weird, but I guess it counts as smart too. It needs a few more comments, but I think it's a good solution. One could delay the backwards memcpy until vmexit time, but that would require a new flag so it's not worth it for what is a pretty rare and already expensive case. Paolo