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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 0899AC433ED for ; Thu, 8 Apr 2021 17:37:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C282A610E5 for ; Thu, 8 Apr 2021 17:37:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232530AbhDHRhu (ORCPT ); Thu, 8 Apr 2021 13:37:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231676AbhDHRho (ORCPT ); Thu, 8 Apr 2021 13:37:44 -0400 Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53E03C061761 for ; Thu, 8 Apr 2021 10:37:33 -0700 (PDT) Received: by mail-pl1-x634.google.com with SMTP id t22so1093408ply.1 for ; Thu, 08 Apr 2021 10:37:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=hVZgbh4zEEXOJBrSWQCq6IMMudTOr92ycubeG9UlX0U=; b=MhfTAti86tKItO88AcfDU5vF5tY1xDstmQO5FJYjR+a5YSx3EvaPy3jEJHDYEQmcK/ aPFlk04sIuXReOxM1199liMx0B//1t9w3buF7geu+CRg7GKZKXeDGn+UWxqZyPyQVGcU Eyq3SIB9uZ5xGlXgEiF2UEVu5QqgqSqCcU7gPToN3O3erVl1suY9qRwLSbdkP2Z+VQSF kIWMw9s8VgLBvZg5PxtmrYBxYgCDMUgqDXW05wm9YdBg+JOMYAaBl8c631KgtpCpuhMX SrQmH7WxZAth0w0tHB/FwWpHXWy+zZ1sBcJDgVJDIR+T81R4h0Jj3D3bOpFDa+wsEPwG 4tww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=hVZgbh4zEEXOJBrSWQCq6IMMudTOr92ycubeG9UlX0U=; b=r8gYjIhSCnGyqIiijEx/3SYxZQdk9mk6WGujl4nz/GP5q1Jtgwi9McPhhtmR9RZy1s z5rmQe0FDBpka3UTeLPJZZkett1S89/+8hSr5prLX7IJ1IqQ8/JjcMK8XzQotPuGW4o4 MFQnmtTYnulO1hGaPu40y8j7NgwUjPyNRDE40JnLAOLqJ3CSBt3IpbM7m11vAFVcZblD YwOsmgwhMim0l3/Pzqv24Xd8Iq4DXLQMdRtRMgqfu/cXIlPrdK6dKRi9Zbkk4uydWFzb 9Dgxa6jUfaVeLWuuKRHw9dqbOTlbEL4riaqmrS4GVC1KaTys/zZr/Qhb31U63o0czjrp rPDA== X-Gm-Message-State: AOAM532BnRoVbqxKpUXc6RYPAERbMW7OmNwbgstks3vUdn9FyF2uEsMq ujU7pCcvplDzg2FEZUuggiR2Ow== X-Google-Smtp-Source: ABdhPJxhENBCnEW26BKzJQRlggIxwanHciEldY60tfSuxbu/j+3CRL/d2SokWC55V/DlHoUVzDqQlQ== X-Received: by 2002:a17:90a:b00c:: with SMTP id x12mr3609139pjq.216.1617903452750; Thu, 08 Apr 2021 10:37:32 -0700 (PDT) Received: from google.com (240.111.247.35.bc.googleusercontent.com. [35.247.111.240]) by smtp.gmail.com with ESMTPSA id x9sm88802pfn.182.2021.04.08.10.37.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Apr 2021 10:37:32 -0700 (PDT) Date: Thu, 8 Apr 2021 17:37:28 +0000 From: Sean Christopherson To: Tom Lendacky Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, Paolo Bonzini , Jim Mattson , Joerg Roedel , Vitaly Kuznetsov , Wanpeng Li , Borislav Petkov , Ingo Molnar , Thomas Gleixner , Brijesh Singh Subject: Re: [PATCH v2] KVM: SVM: Make sure GHCB is mapped before updating Message-ID: References: <1ed85188bee4a602ffad9632cdf5b5b5c0f40957.1617900892.git.thomas.lendacky@amd.com> <923548be-db20-7eea-33aa-571347a95526@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <923548be-db20-7eea-33aa-571347a95526@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 08, 2021, Tom Lendacky wrote: > On 4/8/21 12:10 PM, Sean Christopherson wrote: > > On Thu, Apr 08, 2021, Tom Lendacky wrote: > >> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > >> index 83e00e524513..7ac67615c070 100644 > >> --- a/arch/x86/kvm/svm/sev.c > >> +++ b/arch/x86/kvm/svm/sev.c > >> @@ -2105,5 +2105,8 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) > >> * the guest will set the CS and RIP. Set SW_EXIT_INFO_2 to a > >> * non-zero value. > >> */ > >> + if (WARN_ON_ONCE(!svm->ghcb)) > > > > Isn't this guest triggerable? I.e. send a SIPI without doing the reset hold? > > If so, this should not WARN. > > Yes, it is a guest triggerable event. But a guest shouldn't be doing that, > so I thought adding the WARN_ON_ONCE() just to detect it wasn't bad. > Definitely wouldn't want a WARN_ON(). WARNs are intended only for host issues, e.g. a malicious guest shouldn't be able to crash the host when running with panic_on_warn.