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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 4CA6BC43387 for ; Sat, 22 Dec 2018 17:39:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1427E21A4E for ; Sat, 22 Dec 2018 17:39:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545500386; bh=Oe30/VPEvYZtSxHs+nzPMjB86Z0O/7KVL6T+135d60Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ly5AjtnTUXobSY7szgB+tJETmyBkAnUZlcVIWIHFbM9sM7QCYbDuclpX2hOB4GceR MKf2cfmgrqlNoL5bnsEgLDVONbyDEJ23F0+p1sciR6SlGXoa5vZ/Rdq5Qvk2TJtb/S 9GI9Ur0R4DWSq/bw6HY6nRPbNqVUfPRiWeyoqfoU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392652AbeLVRjp (ORCPT ); Sat, 22 Dec 2018 12:39:45 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:55330 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392627AbeLVRji (ORCPT ); Sat, 22 Dec 2018 12:39:38 -0500 Received: by mail-wm1-f66.google.com with SMTP id y139so7989323wmc.5; Sat, 22 Dec 2018 09:39:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=FGCCJ/VYLbjYtJnfV7b3tl8Z/z2VEa4Rim/Qzw/5Hck=; b=CxIuOaR5FL7L9GBeVLnxzIF3DflS2AazMpxUJ64IDDDc8xq5cwAQdns+QPhM9pZuwd hbvwvTeCcZWViJdh+XYaYPwLnlEiM1Q0zPXmqTJcrGflfPgIZtONgFL7TQCpbOv6GC8v FtFOQMZeezihLg0O8lVEWatKaux5dJjZsm4T9mHHgCDY5gtOsanu2Mt3WUlGclrNsVlQ JdK5QqW4lap1KAN4QHOAF0pgNZT77+AO48cC6r8IljEu9WqAPUdViLdui8tZH8+jp9jm uhGsuFKFrE3Sw5SDOtxj3u9SulRqk4YIFPyeYY3pDh5R6Xzjn5MG2ezzYxZtKco83i2G /p4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=FGCCJ/VYLbjYtJnfV7b3tl8Z/z2VEa4Rim/Qzw/5Hck=; b=TLzdRI/0O0AYXkN9UZr3B9v9a1WSgI5lynJv/Y5vTNIA9BGXiVFlD2RQiB5yHh1gxm bp0FLHoZ8F1GALPmDCU1rSugXHSUVVYxUr1qq/wWwLt6e2pJaC5oYpAb+Dp+Lc7nrrjJ q3A98DRNFYjUsKzPR45BBOMTDa3vbvlQPWaQW7FBpVY0+yCYcqlgI8kGF2aU5NDSDutL aVNZ/loiphe01QJZn0mohBcFmTo0rPH+jZG7So+V2MGBX+HhvgHdzwFxltzhbre6gWk3 01hdlXLSsqumT54AITqCEwKhWcftBdGDAALta6aoz9wPW4qf+/y1mQaZRx1ip+neasKN IUoA== X-Gm-Message-State: AJcUukfKmyztkBmXCwD3Jpv3Id4OAAYrNzw/HajJGv2YQQm21QiJUbsk NUbQQxopgOdARTya/U70mAqIu+o3 X-Google-Smtp-Source: ALg8bN5eUn89gG4rwDOgZnEqjKZIuPX061ji307m1Dyu9nbdkzRnw+9Cj6MhlN4p8ezsOAUM3RxUMg== X-Received: by 2002:a7b:c7c2:: with SMTP id z2mr5845677wmk.47.1545476053776; Sat, 22 Dec 2018 02:54:13 -0800 (PST) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id 126sm26451262wmx.26.2018.12.22.02.54.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 22 Dec 2018 02:54:12 -0800 (PST) Date: Sat, 22 Dec 2018 11:54:10 +0100 From: Ingo Molnar To: Sai Praneeth Prakhya Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, Borislav Petkov , Andy Lutomirski , Dave Hansen , Bhupesh Sharma , Peter Zijlstra , Thomas Gleixner , Ard Biesheuvel Subject: Re: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE Message-ID: <20181222105410.GA130780@gmail.com> References: <20181222022234.7573-1-sai.praneeth.prakhya@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181222022234.7573-1-sai.praneeth.prakhya@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Sai Praneeth Prakhya wrote: > Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions > from efi_pgd") forgets to take two EFI modes into consideration namely > EFI_OLD_MEMMAP and EFI_MIXED_MODE. So the commit sha1 ended up being this one in tip:efi/core: 08cfb38f3ef4: x86/efi: Unmap EFI boot services code/data regions from efi_pgd > EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir > using ioremap() and init_memory_mapping(). This feature can be enabled by > passing "efi=old_map" as kernel command line argument. But, > efi_unmap_pages() unmaps EFI boot services code/data regions *only* from > efi_pgd and hence cannot be used for unmapping EFI boot services code/data > regions from swapper_pg_dir. > > Introduce a temporary fix to not unmap EFI boot services code/data regions > when EFI_OLD_MEMMAP is enabled while working on a real fix. > > EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a > 64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE, > all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY, > EFI_LOADER_, EFI_BOOT_SERVICES_ and > EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to > facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence, > don't unmap EFI boot services code/data regions when booted in mixed mode. > > Signed-off-by: Sai Praneeth Prakhya > Cc: Borislav Petkov > Cc: Ingo Molnar > Cc: Andy Lutomirski > Cc: Dave Hansen > Cc: Bhupesh Sharma > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Ard Biesheuvel > --- > arch/x86/platform/efi/quirks.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c > index 09e811b9da26..9c34230aaeae 100644 > --- a/arch/x86/platform/efi/quirks.c > +++ b/arch/x86/platform/efi/quirks.c > @@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md) > u64 pa = md->phys_addr; > u64 va = md->virt_addr; > > + /* > + * To Do: Remove this check after adding functionality to unmap EFI boot > + * services code/data regions from direct mapping area because > + * "efi=old_map" maps EFI regions in swapper_pg_dir. > + */ > + if (efi_enabled(EFI_OLD_MEMMAP)) > + return; > + > + /* > + * EFI mixed mode has all RAM mapped to access arguments while making > + * EFI runtime calls, hence don't unmap EFI boot services code/data > + * regions. > + */ > + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED)) > + return; I suppose old_mmap and mixed mode stopped working altogether after the unmapping changes? What are the symptoms, instant reboots, crasher, or some more benign behavior like non-working runtime EFI functionality? If Ard acks this I'll apply it immediately, as these bugs look like show-stoppers for merging the EFI tree into v4.21. Thanks, Ingo