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=-7.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 24D87C352A2 for ; Fri, 7 Feb 2020 09:22:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE5EF20726 for ; Fri, 7 Feb 2020 09:22:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ANcxrCYb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726728AbgBGJWx (ORCPT ); Fri, 7 Feb 2020 04:22:53 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:26705 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726451AbgBGJWx (ORCPT ); Fri, 7 Feb 2020 04:22:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581067371; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9G854gH0yt32vL5cWXqi6Q0NJ8XwpZFZsqnHu0e32+o=; b=ANcxrCYb+7DBgoK0lwmyTR6bJKpr+myxvj0MHbb2l6+gRvwGQ+yh1Iqk+BIELU21RThqct Gc20yaWujQ8t5dUgkUuo6Jpx3n74QgveN04mJvyjme2a+kkIITyrwvOOmQ8LcIAm8P1adv eAU+irEPIwirSYOT9qvzq0ySiOg/vhU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-146-1bZ4vXbeOeOcU3F6bYifiw-1; Fri, 07 Feb 2020 04:22:49 -0500 X-MC-Unique: 1bZ4vXbeOeOcU3F6bYifiw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0C36A1088382; Fri, 7 Feb 2020 09:22:48 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-117-138.ams2.redhat.com [10.36.117.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9E9DD1001B05; Fri, 7 Feb 2020 09:22:45 +0000 (UTC) Subject: Re: [PATCH 0/2] arch-agnostic initrd loading method for EFI systems From: Laszlo Ersek To: Ard Biesheuvel , linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, leif@nuviainc.com, pjones@redhat.com, mjg59@google.com, agraf@csgraf.de, ilias.apalodimas@linaro.org, xypron.glpk@gmx.de, daniel.kiper@oracle.com References: <20200206140352.6300-1-ardb@kernel.org> Message-ID: Date: Fri, 7 Feb 2020 10:22:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On 02/07/20 10:09, Laszlo Ersek wrote: > On 02/06/20 15:03, Ard Biesheuvel wrote: >> This series introduces an arch agnostic way of loading the initrd into >> memory from the EFI stub. This addresses a number of shortcomings that >> affect the current implementations that exist across architectures: >> >> - The initrd= command line option can only load files that reside >> on the same file system that the kernel itself was loaded from, which >> requires the bootloader or firmware to expose that file system via the >> appropriate EFI protocol, which is not always feasible. From the kernel >> side, this protocol is problematic since it is incompatible with mixed >> mode on x86 (this is due to the fact that some of its methods have >> prototypes that are difficult to marshall) >> >> - The approach that is ordinarily taken by GRUB is to load the initrd into >> memory, and pass it to the kernel proper via the bootparams structure or >> via the device tree. This requires the boot loader to have an understanding >> of those structures, which are not always set in stone, and of the policies >> around where the initrd may be loaded into memory. In the ARM case, it >> requires GRUB to modify the hardware description provided by the firmware, >> given that the initrd base and offset in memory are passed via the same >> data structure. It also creates a time window where the initrd data sits >> in memory, and can potentially be corrupted before the kernel is booted. >> >> Considering that we will soon have new users of these interfaces (EFI for >> kvmtool on ARM, RISC-V in u-boot, etc), it makes sense to add a generic >> interface now, before having another wave of bespoke arch specific code >> coming in. >> >> Another aspect to take into account is that support for UEFI secure boot >> and measured boot is being taken into the upstream, and being able to >> rely on the PE entry point for booting any architecture makes the GRUB >> vs shim story much cleaner, as we should be able to rely on LoadImage >> and StartImage on all architectures, while retaining the ability to >> load initrds from anywhere. >> >> Note that these patches depend on a fair amount of cleanup work that I >> am targetting for v5.7. Branch can be found at: >> https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=efistub-unification2 >> >> An implementation for ArmVirtQemu (OVMF for ARM aka AAVMF) can be found >> at https://github.com/ardbiesheuvel/edk2/commits/linux-efi-generic. >> The change is for ARM only, but the exact same code could be used on x86. > > I like this ArmVirtQemu feature, but I think it should be implemented as > an addition, rather than a replacement. Older kernels (older EFI stubs) > will try to fetch the initrd from the same fs where grub loaded the > kernel from (exactly as you describe in the blurb). > > For example, virt-install's "--location" option "can recognize certain > distribution trees and fetches a bootable kernel/initrd pair to launch > the install". It would be nice to keep that working for older distros. > > I think LoadFile[2] can co-exist with SimpleFs. > > I also think that the "try SimpleFs first, fall back to LoadFile[2] > second" requirement applies only to the UEFI boot manager, and not to > the kernel's EFI stub. IOW in the new approach the kernel is free to > ignore (abandon) the old approach for good. ... But that might not be good for compatibility with grub and/or the platform firmware, from the kernel's own perspective, perhaps?... Who is supposed to produce LoadFile2 with the new VenMedia devpath? Thanks Laszlo >> >> Cc: lersek@redhat.com >> Cc: leif@nuviainc.com >> Cc: pjones@redhat.com >> Cc: mjg59@google.com >> Cc: agraf@csgraf.de >> Cc: ilias.apalodimas@linaro.org >> Cc: xypron.glpk@gmx.de >> Cc: daniel.kiper@oracle.com >> >> Ard Biesheuvel (2): >> efi/libstub: add support for loading the initrd from a device path >> efi/libstub: take noinitrd cmdline argument into account for devpath >> initrd >> >> drivers/firmware/efi/libstub/arm-stub.c | 21 ++++-- >> .../firmware/efi/libstub/efi-stub-helper.c | 74 +++++++++++++++++++ >> drivers/firmware/efi/libstub/efistub.h | 13 ++++ >> drivers/firmware/efi/libstub/x86-stub.c | 51 ++++++++++--- >> include/linux/efi.h | 1 + >> 5 files changed, 146 insertions(+), 14 deletions(-) >> >