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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 73175C43331 for ; Thu, 5 Sep 2019 15:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A27F820820 for ; Thu, 5 Sep 2019 15:21:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="KAkWOu+x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390021AbfIEPVh (ORCPT ); Thu, 5 Sep 2019 11:21:37 -0400 Received: from ste-pvt-msa2.bahnhof.se ([213.80.101.71]:61181 "EHLO ste-pvt-msa2.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388057AbfIEPVg (ORCPT ); Thu, 5 Sep 2019 11:21:36 -0400 Received: from localhost (localhost [127.0.0.1]) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTP id D8C7F3F478; Thu, 5 Sep 2019 17:21:28 +0200 (CEST) Authentication-Results: ste-pvt-msa2.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=KAkWOu+x; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Authentication-Results: ste-ftg-msa2.bahnhof.se (amavisd-new); dkim=pass (1024-bit key) header.d=shipmail.org Received: from ste-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (ste-ftg-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WTG1gvVG6mPF; Thu, 5 Sep 2019 17:21:27 +0200 (CEST) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id B49B73F6DE; Thu, 5 Sep 2019 17:21:24 +0200 (CEST) Received: from localhost.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 40C64360160; Thu, 5 Sep 2019 17:21:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1567696884; bh=NG8liGCrurC3Kiw5aHunM7ayFbaO22LNknP8UX20R8A=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=KAkWOu+xaC7GJBsRMY4xoJkMaq6SYn/mhV+QeVqOHLj/AZGAbCSmFa+29JWCp4jNY hsM9PrQd/CgGI1evlVZ0n3opn8VR7YSQudWfMfFKBNYRnikSuGdIbkJK91RDncpdD5 FDyyTmK+JjSyGOcuFr7Y/vhb+2fdEKmfzPIocJ7Q= Subject: Re: [RFC PATCH 1/2] x86: Don't let pgprot_modify() change the page encryption bit To: Dave Hansen , linux-kernel@vger.kernel.org, x86@kernel.org, pv-drivers@vmware.com Cc: Thomas Hellstrom , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Christoph Hellwig , =?UTF-8?Q?Christian_K=c3=b6nig?= , Marek Szyprowski , Tom Lendacky References: <20190905103541.4161-1-thomas_os@shipmail.org> <20190905103541.4161-2-thomas_os@shipmail.org> <608bbec6-448e-f9d5-b29a-1984225eb078@intel.com> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28VMware=29?= Organization: VMware Inc. Message-ID: Date: Thu, 5 Sep 2019 17:21:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <608bbec6-448e-f9d5-b29a-1984225eb078@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/5/19 4:15 PM, Dave Hansen wrote: > Hi Thomas, > > Thanks for the second batch of patches! These look much improved on all > fronts. Yes, although the TTM functionality isn't in yet. Hopefully we won't have to bother you with those though, since this assumes TTM will be using the dma API. > On 9/5/19 3:35 AM, Thomas Hellström (VMware) wrote: >> -/* mprotect needs to preserve PAT bits when updating vm_page_prot */ >> +/* >> + * mprotect needs to preserve PAT and encryption bits when updating >> + * vm_page_prot >> + */ >> #define pgprot_modify pgprot_modify >> static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) >> { >> - pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK; >> - pgprotval_t addbits = pgprot_val(newprot); >> + pgprotval_t preservebits = pgprot_val(oldprot) & >> + (_PAGE_CHG_MASK | sme_me_mask); >> + pgprotval_t addbits = pgprot_val(newprot) & ~sme_me_mask; >> return __pgprot(preservebits | addbits); >> } > _PAGE_CHG_MASK is claiming similar functionality about preserving bits > when changing PTEs: > >> /* >> * Set of bits not changed in pte_modify. The pte's >> * protection key is treated like _PAGE_RW, for >> * instance, and is *not* included in this mask since >> * pte_modify() does modify it. >> */ >> #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ >> _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ >> _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) > This makes me wonder if we should be including sme_me_mask in > _PAGE_CHG_MASK (logically). I was thinking the same. But what confuses me is that addbits isn't masked with ~_PAGE_CHG_MASK, which is needed for sme_me_mask, since the problem otherwise is typically that the encryption bit is incorrectly set in addbits. I wonder whether it's an optimization or intentional. /Thomas