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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 1CDDEC433DF for ; Mon, 1 Jun 2020 07:28:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1B23206C3 for ; Mon, 1 Jun 2020 07:28:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TPAb6mEo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726322AbgFAH2O (ORCPT ); Mon, 1 Jun 2020 03:28:14 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:59927 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725283AbgFAH2N (ORCPT ); Mon, 1 Jun 2020 03:28:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590996491; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rBGnBe9nAKzVkNp1oiiFdwiEMaoCXpO5GvmbNaHYZEA=; b=TPAb6mEogHV8+LfFHYuWbjNvmV9d4ksqqjyF1uNY6Vc+nYTCls6/ZxjkZrxTxca6Grc45h /D4ghTlq4i6YJTziyMKZX+yJ9t3hDXFST8D2MzGWBdLl7mBiCEAd3xL3Clmud5H7IGYpOa bsPAUxMqb+vg2RZydnu3zkZTrOIJAJA= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-301-LI45Nma3ORuBC8qQqJnGLg-1; Mon, 01 Jun 2020 03:28:09 -0400 X-MC-Unique: LI45Nma3ORuBC8qQqJnGLg-1 Received: by mail-wm1-f71.google.com with SMTP id g84so2347223wmf.4 for ; Mon, 01 Jun 2020 00:28:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rBGnBe9nAKzVkNp1oiiFdwiEMaoCXpO5GvmbNaHYZEA=; b=Get8yLt0M61j768u68kP1SCMkf6QbIeP12NPcQMkweZFHm9A34ob2J7x3RGqlxwrq4 6rjDx1N1zSzpCabA1gNNkfNyjywhkwOUmMGlefQa3xqlloA3SIwxNTeu0kkuRyXbApWv NgmRmsAcBlUUDRnhCSg7pykcMsTdLb3BCuRuHkTEDZwaimtBR4yjHFDdzPlUi9EkIJQc /zc2SydBpUE8RU+tslkE6/CpetJcAd+YC6G0UOYbq/1nzhQpSwEXgju1pJf1ac73ITJg KEe5UHOVeJxu0Q+u1UDtcO62vS66J6L+GtMy/pC4Sh15WFPMXxSFbgIgZarODZNrUuQQ FeSA== X-Gm-Message-State: AOAM5319fXw33epC7DVx7mSLMkEGXYvZnW904WpXe48AUJ6aiW+j40Us /CDkb6HXsCN/tRmgoxSBZL1p7TY/NyqxoPzKtfCDxTtdz9eYUYGomJnT7d6Jy9ok+ptxnF4cJXK hFfaLOn77N+IKIgjGkooTszfz X-Received: by 2002:a05:600c:1:: with SMTP id g1mr19913786wmc.142.1590996488357; Mon, 01 Jun 2020 00:28:08 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxyQPU8guSVwXTyixwCAix1YqbDNU3KwWv/HjBxt0m9SQOj/RtfZn4b9HR9UnvFILpXKqx3og== X-Received: by 2002:a05:600c:1:: with SMTP id g1mr19913773wmc.142.1590996488118; Mon, 01 Jun 2020 00:28:08 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:e044:3d2:1991:920c? ([2001:b07:6468:f312:e044:3d2:1991:920c]) by smtp.gmail.com with ESMTPSA id i74sm19645977wri.49.2020.06.01.00.28.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 01 Jun 2020 00:28:07 -0700 (PDT) Subject: Re: [PATCH 25/30] KVM: nSVM: leave guest mode when clearing EFER.SVME To: Krish Sadhukhan , linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <20200529153934.11694-1-pbonzini@redhat.com> <20200529153934.11694-26-pbonzini@redhat.com> From: Paolo Bonzini Message-ID: <9319ccf9-c318-40e8-7d56-df0e32617430@redhat.com> Date: Mon, 1 Jun 2020 09:28:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/20 04:26, Krish Sadhukhan wrote: > On 5/29/20 8:39 AM, Paolo Bonzini wrote: >> According to the AMD manual, the effect of turning off EFER.SVME while a >> guest is running is undefined.  We make it leave guest mode immediately, >> similar to the effect of clearing the VMX bit in MSR_IA32_FEAT_CTL. > > I see that svm_set_efer() is called in enter_svm_guest_mode() and > nested_svm_vmexit(). In the VMRUN path, we have already checked > EFER.SVME in nested_vmcb_checks(). So if it was not set, we wouldn't > come to enter_svm_guest_mode(). Your fix is only for the #VMEXIT path > then ? No, it's for KVM_SET_MSR. Paolo