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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 DB89EC433DF for ; Thu, 20 Aug 2020 17:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B8E620885 for ; Thu, 20 Aug 2020 17:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597945891; bh=Hd7dQCZl4iX+4WliBBdnAj0CCq4bi2DQ3q+O7Ti6Nlg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=I7icew+Ta4JB4pzEqZstoj42ZppUIVKUP6JsUy4fy9ja9MCRtQfJlWXA6S2U5+cGH hy+VU9PXYx4c8BAn63XYrE78ikzFHUK7DVrol/3EiLIb01MuXAL+OVDv5vsBrjA3l4 mm/XMrTmI555otACpQRT2blkQwGF6ui5H+jbPdAY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726896AbgHTRv3 (ORCPT ); Thu, 20 Aug 2020 13:51:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:57580 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725859AbgHTRvY (ORCPT ); Thu, 20 Aug 2020 13:51:24 -0400 Received: from mail-wm1-f51.google.com (mail-wm1-f51.google.com [209.85.128.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 41E9A22B47 for ; Thu, 20 Aug 2020 17:51:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597945883; bh=Hd7dQCZl4iX+4WliBBdnAj0CCq4bi2DQ3q+O7Ti6Nlg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=Im+4gBzl5bMAbo5vl1UwPaLrbBNkZB3oa0hi94GLj5UtzODGxtqGempxVlLZ6SyAN DWUTs3AziuArOpNOWYiwlXGA3yelXsbpk+EPT+DZQBHhOpNrdYm/EGPU0MyeMKr3oP qIQxfSVS2YOdxm67vTzEAebMWTZQhZkNX5qFMfVE= Received: by mail-wm1-f51.google.com with SMTP id x5so2454265wmi.2 for ; Thu, 20 Aug 2020 10:51:23 -0700 (PDT) X-Gm-Message-State: AOAM530kTY5HCkb4uo5Va8aX+exGMKrdBOee18QjKMgrbR3QogLxIh7a 25ja/pyvMU72A6KUUITyEb65fql8EB88LC/QXCnccg== X-Google-Smtp-Source: ABdhPJxcfh3w4DsaGHJOKg/5/rhLHj1LNmJV95DlNJr3n5TBlCyXcbFkCp4plyjTDN2OBa0gvhasE/RmvsvqVvaV5zA= X-Received: by 2002:a1c:7e02:: with SMTP id z2mr4577943wmc.138.1597945881693; Thu, 20 Aug 2020 10:51:21 -0700 (PDT) MIME-Version: 1.0 References: <39d57e4d-5db4-f536-6f5e-6b0414c0dccc@amd.com> <7dedb0ab-56a6-5d96-577b-21ab1ecdad24@amd.com> In-Reply-To: From: Andy Lutomirski Date: Thu, 20 Aug 2020 10:51:10 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: FSGSBASE causing panic on 5.9-rc1 To: Paolo Bonzini Cc: Andy Lutomirski , Tom Lendacky , Joerg Roedel , "Christopherson, Sean J" , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Linux Kernel Mailing List , X86 ML , "Chang S. Bae" , Thomas Gleixner , Sasha Levin , Borislav Petkov , Peter Zijlstra , Ingo Molnar Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 20, 2020 at 6:43 AM Paolo Bonzini wrote: > > On 19/08/20 23:25, Andy Lutomirski wrote: > > wrmsrl(MSR_KERNEL_GS_BASE, current->thread.gsbase); > > load_gs_index(svm->host.gs); > > > > Surely that should do load_gs_index() *before* wrmsrl(). But that's > > not the problem at hand. > > The wrmsrl is writing the inactive GS base so the ordering between > load_gs_index and wrmsrl(MSR_KERNEL_GS_BASE) should be irrelevant? load_gs_index() sets the index between a pair of swapgs's -- it writes the inactive base, too. --Andy