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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40A8EEE3F0C for ; Tue, 12 Sep 2023 19:24:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237503AbjILTYO (ORCPT ); Tue, 12 Sep 2023 15:24:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235683AbjILTYK (ORCPT ); Tue, 12 Sep 2023 15:24:10 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EA5C199; Tue, 12 Sep 2023 12:24:07 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BF55C433C8; Tue, 12 Sep 2023 19:24:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694546646; bh=bSeMPRZdOhqkBgklu+WQU2Wv24CUcxj6J17hMG5Lse0=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=PuI6NTqXJU1+0eeCQYHD6rSEuEYw4ZnM7mBwYquu/sX0RvZH+Jhs7y9VRQkXhAbyL xBvBsyU+FexIyvaMBqcQoJ6f+2C0zRl+2rA+gk/kPp2QYtl/oQ3HuUV2k1eTYpyz7p G+fwu6SXNVSexF23NKb+yri94kKCM6DLC2PUHoRXBgfOrC3CrFJHRyQGLM+M5kSsXT /w27UER/0O/7DX9XtgOxXptOnlh3oq3lui/4zirGGH/q0WXC035zHXSPWzoeabA0nM wyMWxvI5fFipZfe1Csmf3y2PeV2dOS0fC1lm5wCCfIVauFamAMBjbOUEwEecN1jxny VVALdgkrEmIlA== Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 12 Sep 2023 22:24:02 +0300 Message-Id: Cc: , , , , , , , "Baoquan He" , , , "Luca Boccassi" Subject: Re: [PATCH 0/1] x86/kexec: UKI support From: "Jarkko Sakkinen" To: "Jan Hendrik Farr" , X-Mailer: aerc 0.14.0 References: <20230909161851.223627-1-kernel@jfarr.cc> <1d974586-1bf7-42e8-9dae-e5e41a3dbc9f@app.fastmail.com> <9580df76-c143-4077-8a39-b1fcc0ed37bd@app.fastmail.com> <5a67051d-eb21-4a96-acc4-40f829a59e23@app.fastmail.com> In-Reply-To: <5a67051d-eb21-4a96-acc4-40f829a59e23@app.fastmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue Sep 12, 2023 at 9:56 PM EEST, Jan Hendrik Farr wrote: > > What sort of bottleneck does the EFI stub have so that we need yet > > another envelope? > > Well I can come up with a few advantages of UKI compared to normal bzImag= e with builtin initrd and cmdline. > > 1. You already identified this one. Using addons to adjust your cmdline It is not a benefit as this is already possible today. > 2. I can use my normal initramfs generation tooling. Just install my > compiled kernel, my distros install script will generate the > initramfs. Then I package it up as a UKI. This will be a lot more > awkward with a builtin initrd. > 3. Measured boot. You can place PCR signatures in the UKI using > systemd-measure. This will sign the expected PCR values for booting > this UKI. I think with normal bzImage this will be a lot more > difficult. If you place those PCR signatures in the builtin initrd > this will change the kernel image which means now the values you > signed no longer match (depending on how you measure the kernel; I > don't think the normal EFI stub even measures the kernel in first > place, but I could be mistaken about this) > 4. UKIs are automatically recognized by systemd-boot These are sort of "tautological" arguments. There must be some objective reasons why this architecture was chosen instead of other (i.e. using what already pre-exists). BR, Jarkko