From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) by spool.mail.gandi.net (Postfix) with ESMTPS id 6DC37D81096 for ; Wed, 6 Dec 2023 15:27:32 +0000 (UTC) DKIM-Signature: a=rsa-sha256; bh=8J25YwoLP4oD2+CDzv/m2vbeO/ELFlk/rrVmbqJvKxM=; c=relaxed/simple; d=groups.io; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:In-Reply-To:Precedence:List-Subscribe:List-Help:Sender:List-Id:Mailing-List:Delivered-To:Reply-To:List-Unsubscribe-Post:List-Unsubscribe:Content-Type:Content-Disposition; s=20140610; t=1701876451; v=1; b=Oqp6Zb4sueirTuiWor3xBh+PCfypX8i0Y3QSmTJc5cUA9lvfmEZP7y3VjyB2p1sshK49hHXt 4BGjZGofZSKytmzKZKkHrHEFcXqkX4NsznS2BMUZweUVDqMuoA4RBPALZUuA4dICMA2NyX/8p0b DuxTIJp3KQAOsKsIDI1dT7NQ= X-Received: by 127.0.0.2 with SMTP id zYtRYY7687511xzdIadTXPgQ; Wed, 06 Dec 2023 07:27:31 -0800 X-Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by mx.groups.io with SMTP id smtpd.web11.34188.1701876450326753351 for ; Wed, 06 Dec 2023 07:27:30 -0800 X-Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-145-yCVXIm8EOuez7Q-4Rkv_TA-1; Wed, 06 Dec 2023 10:27:23 -0500 X-MC-Unique: yCVXIm8EOuez7Q-4Rkv_TA-1 X-Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3864B185A785; Wed, 6 Dec 2023 15:27:23 +0000 (UTC) X-Received: from dobby.home.kraxel.org (unknown [10.39.194.62]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E77FA492BE6; Wed, 6 Dec 2023 15:27:22 +0000 (UTC) X-Received: by dobby.home.kraxel.org (Postfix, from userid 1000) id 98EA27A434; Wed, 6 Dec 2023 16:27:21 +0100 (CET) Date: Wed, 6 Dec 2023 16:27:21 +0100 From: "Gerd Hoffmann" To: devel@edk2.groups.io, ardb@kernel.org Cc: Taylor Beebe , Oliver Smith-Denny , Peter Jones , Ard Biesheuvel , =?utf-8?B?TO+/vXN6bO+/vSDvv71yc2Vr?= , Oliver Steffen , Alexander Graf , Leif Lindholm Subject: Re: [edk2-devel] [PATCH] ArmVirtPkg: Allow EFI memory attributes protocol to be disabled Message-ID: References: <20231204095215.1053032-1-ardb@google.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Precedence: Bulk List-Subscribe: List-Help: Sender: devel@edk2.groups.io List-Id: Mailing-List: list devel@edk2.groups.io; contact devel+owner@edk2.groups.io Reply-To: devel@edk2.groups.io,kraxel@redhat.com List-Unsubscribe-Post: List-Unsubscribe=One-Click List-Unsubscribe: X-Gm-Message-State: q5Z7c7Ee6kwuWExtNtv5fsOkx7686176AA= Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-GND-Status: LEGIT Authentication-Results: spool.mail.gandi.net; dkim=pass header.d=groups.io header.s=20140610 header.b=Oqp6Zb4s; spf=pass (spool.mail.gandi.net: domain of bounce@groups.io designates 66.175.222.108 as permitted sender) smtp.mailfrom=bounce@groups.io; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=redhat.com (policy=none) Hi, > But what we might do is invent a way to avoid setting the XP attribute > on the entire region based on some heuristic. Given that the main > purpose of the EFI memory attribute protocol is to provide the ability > to remove XP (and set RO instead), perhaps we can avoid the set > entirely? Just brainstorming here. Can the fault handler deal with this? Set a flag somewhere, print a big'n'fat error message, wait 5 secs, reset machine? After reset the firmware will see the flag and come up in 'compat' instead of 'strict' mode. Not sure what a good place for such a flag would be. Do we have other options than a non-volatile efi variable? When using a efi variable we probably should add an 'expires' timestamp, so the machine doesn't stay in 'compat' mode forever. > (cc'ing Taylor and Oliver given that this is related to the memory > policy work as well) Perhaps we can use the fact that the active image > is non-NX compat to make some tweaks? Memory policies would be another candidate which could possibly use a less strict profile in 'compat' mode. I'd love to see memory policies land for the February stable tag. > What I really want to avoid is derail our effort to tighten things > down and comply with the NX compat related policies, by adding some > build time control that the distros will enable now and never disable > again, citing backward compat concerns. Sure, I want that too. Having an runtime switch is already an improvement over having a compile time switch. Having this working fully automatic would be even better of course. > And the deafening silence from the shim developers is not an > encouragement either. Indeed. take care, Gerd -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#112129): https://edk2.groups.io/g/devel/message/112129 Mute This Topic: https://groups.io/mt/102967690/7686176 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io] -=-=-=-=-=-=-=-=-=-=-=-