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=-1.1 required=3.0 tests=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 10F34C433E1 for ; Wed, 24 Jun 2020 14:15:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E06B620823 for ; Wed, 24 Jun 2020 14:15:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593008123; bh=b7QM/AnAF2FLjRffq2R666yrcagu50c8AB3ZQJKmq98=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=r6PbyNtd02YctM+RFVP7vUMTJtPScS9Fe3k7PiCZNtPYf7TTM1N1IT6hOkiT9P6uk sb5wlwFyZ4t1PsXVjAQgg4mUpRRqfWcNZKlIW2Ihp4GikVUsuUfQ6Dei61ae6E+xtN d3qA64jBBTsbaBfIOmsGgzttQH6+9sjisCXimqfk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391146AbgFXOPW (ORCPT ); Wed, 24 Jun 2020 10:15:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:49352 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389682AbgFXOPW (ORCPT ); Wed, 24 Jun 2020 10:15:22 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 806132076E; Wed, 24 Jun 2020 14:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593008121; bh=b7QM/AnAF2FLjRffq2R666yrcagu50c8AB3ZQJKmq98=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DOahzyNiRhEpLN5dUFOi42BNnIooay0Op/7I7YVPOOm8VDNPk48W/QwucjAF7hizb YkeCU3EKTwrUERjUHBSDaJLTIOeU1A255t/d0el+aEkmiTgOcyURiX08GP4QYD7h00 ApMHDwF21UoDCm4KeXgiwAaPUUjoV4ccFw/y4xB4= Date: Wed, 24 Jun 2020 10:15:20 -0400 From: Sasha Levin To: "Rantala, Tommi T. (Nokia - FI/Espoo)" Cc: "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "pbonzini@redhat.com" Subject: Re: [PATCH 4.14 038/190] KVM: x86: only do L1TF workaround on affected processors Message-ID: <20200624141520.GF1931@sasha-vm> References: <20200619141633.446429600@linuxfoundation.org> <20200619141635.473250358@linuxfoundation.org> <6610924417787ad9e2332d399b5948ce19fbd6fc.camel@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <6610924417787ad9e2332d399b5948ce19fbd6fc.camel@nokia.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 24, 2020 at 12:00:59PM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote: >On Fri, 2020-06-19 at 16:31 +0200, Greg Kroah-Hartman wrote: >> From: Paolo Bonzini >> >> [ Upstream commit d43e2675e96fc6ae1a633b6a69d296394448cc32 ] >> >> KVM stores the gfn in MMIO SPTEs as a caching optimization. These are >> split >> in two parts, as in "[high 11111 low]", to thwart any attempt to use these >> bits >> in an L1TF attack. This works as long as there are 5 free bits between >> MAXPHYADDR and bit 50 (inclusive), leaving bit 51 free so that the MMIO >> access triggers a reserved-bit-set page fault. > >Hi, I'm now seeing this warning in VM bootup with 4.14.y Thanks for the report! >Not seen with 4.19.129 and 5.4.47 that also included this commit. > >Any ideas what's missing in 4.14 ? I think that this was because we're missing 6129ed877d40 ("KVM: x86/mmu: Set mmio_value to '0' if reserved #PF can't be generated"). I've queued it up (along with a few other related commits) and a new -rc cycle should be underway for those. -- Thanks, Sasha