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 aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id C41ACC433F5 for ; Wed, 9 Mar 2022 21:37:22 +0000 (UTC) Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by mx.groups.io with SMTP id smtpd.web10.2449.1646861841408172171 for ; Wed, 09 Mar 2022 13:37:22 -0800 Authentication-Results: mx.groups.io; dkim=missing; spf=neutral (domain: denx.de, ip: 46.255.230.98, mailfrom: pavel@denx.de) Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id D53331C0B77; Wed, 9 Mar 2022 22:37:16 +0100 (CET) Date: Wed, 9 Mar 2022 22:37:16 +0100 From: Pavel Machek To: cip-dev@lists.cip-project.org, jan.kiszka@siemens.com, masami.ichikawa@miraclelinux.com Subject: Fun ahead -- speculation problems being patched in 5.10.105 Message-ID: <20220309213716.GA9983@duo.ucw.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ibTvN161/egqYuK8" Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 09 Mar 2022 21:37:22 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/7684 --ibTvN161/egqYuK8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! It looks like 5.10.105 will be "fun" release. There's big series of arm64 related speculation tweaks, including |61f85b56f 558c30 o: 5.10| arm64: Mitigate spectre style branch history si= de channels And apparently there are some problems on x86-64 side, too: |d185aa3cb e9b601 .: 5.10| x86/speculation: Update link to AMD speculation= whitepaper |edc29f23a eafd98 o: 5.10| x86/speculation: Warn about Spectre v2 LFENCE m= itigation |67997c824 0de05d o: 5.10| x86/speculation: Warn about eIBRS + LFENCE + Un= privileged eBPF + SMT We have seen worse stuff for a hardware bug mitigation before. Scary thing here is that arm64 patches are queued against 5.10 but not 4.19 or earlier. Let me reiterate again that using complex out-of-order CPU is a bad idea if you care about security. Let me reiterate that JITs such as eBPF are complex/dangerous and especially unpriviledged eBPF is risky. v |316f1dd5e 44a391 o: 5.10| x86/speculation: Include unprivileged eBPF sta= tus in Spectre v2 mitigation reporting Best regards, Pavel --=20 DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --ibTvN161/egqYuK8 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCYikeDAAKCRAw5/Bqldv6 8sjaAJ47hef9a+elO0OiBWv7LO2UAN6FkgCfR4OzaO8oHz7qUpBAZeM2aM3tY/g= =uIl3 -----END PGP SIGNATURE----- --ibTvN161/egqYuK8--