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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 5FD13C10F14 for ; Sun, 6 Oct 2019 18:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37CD52080F for ; Sun, 6 Oct 2019 18:07:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570385222; bh=m4BBRy0bCRgpg2FTvrM5XMjhnhRRdyKZ/3eSot2H4sQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=E7R4w0mufpqboEWaIjJcOG5U1YCS8ISRu8zlCZRMFpe6rRlwu8MIO/CXDwAuQ2Wca sXG3zp3oIOsGgPxQY+IEoKyZu0uNgUGYBex/PB/or49w0c86HbArq/DjHZCVnmP2dW ykF93MmF/e1BBLFdfAF6WoWelTo0amCouuOoHF34= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbfJFSHB (ORCPT ); Sun, 6 Oct 2019 14:07:01 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:39537 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726443AbfJFSHB (ORCPT ); Sun, 6 Oct 2019 14:07:01 -0400 Received: by mail-lj1-f195.google.com with SMTP id y3so11291133ljj.6 for ; Sun, 06 Oct 2019 11:06:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=LYZhJ8z29L9VXaq40W7IaPRpHSPw3yWamQCRA+/ko3U=; b=bGADQTdQUdcHqbYbNLqk9QwKozcUBscZ2f20slYeCKfCvmhN38YzMKFvX2ufUc7FXY ODiodrltVBR1zqdLTv38xj3MP/5BMFzRTbjwiz51A8ILCCXUKeHQexCepEAVI85inw7X VnAVOK7Rvj9ezJaN6A43dtjOY05DLDXYKJxuQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=LYZhJ8z29L9VXaq40W7IaPRpHSPw3yWamQCRA+/ko3U=; b=Ct/fkEnzpyVmEp/IOX399QyRjhHEa2RI+QjevTMPeqGb1wu+oH93mrfe7dhpD1afx1 hfvHyXqdefMZthGcbGFurlUhRpbK7EmqKaQE0tZ7SmNpB0DJtyj1s80fqZd7IzyxzHr6 c2nsFe6RzllJGuU6GFPHorLOIoF9iKisqcnxnbJ8I6Tfg8tC8MSku51i5B9Yp25GH2Kq 14qZe7aJQ+Z53aklnu0PwrHwB9cCBo5ix/w+LwrVYdnrt0BAJfKAUZWNzKqp4sjcYlkV ezK06Q+hUf8mlegbJTpVwaWojG+XWyTXvgTus2oMM5+5sZLmREdL73JHTgOw3XnijW6i Oh7w== X-Gm-Message-State: APjAAAWc6QWxFsWSuWYgguJ5AoPuznrmf92V3okFIbzqtJS9LOr7xL8E o+3K3wNZ4MCrjMzN8oJw++lRB6h/2YY= X-Google-Smtp-Source: APXvYqxl7Yi78ER+qSOIF1u82NyFH6Xm7K17/2FM+VrkSru27m4vAxPvzYR0OnpdWhvGLdOQWYj9Eg== X-Received: by 2002:a2e:84d0:: with SMTP id q16mr16057961ljh.106.1570385216821; Sun, 06 Oct 2019 11:06:56 -0700 (PDT) Received: from mail-lj1-f179.google.com (mail-lj1-f179.google.com. [209.85.208.179]) by smtp.gmail.com with ESMTPSA id q24sm2422376lfa.94.2019.10.06.11.06.54 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 06 Oct 2019 11:06:55 -0700 (PDT) Received: by mail-lj1-f179.google.com with SMTP id 7so11281963ljw.7 for ; Sun, 06 Oct 2019 11:06:54 -0700 (PDT) X-Received: by 2002:a2e:9556:: with SMTP id t22mr15616404ljh.97.1570385214720; Sun, 06 Oct 2019 11:06:54 -0700 (PDT) MIME-Version: 1.0 References: <20191006114129.GD24605@amd> <20191006173501.GA31243@amd> In-Reply-To: <20191006173501.GA31243@amd> From: Linus Torvalds Date: Sun, 6 Oct 2019 11:06:38 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: x86/random: Speculation to the rescue To: Pavel Machek Cc: Thomas Gleixner , "Ahmed S. Darwish" , LKML , "Theodore Ts'o" , Nicholas Mc Guire , "the arch/x86 maintainers" , Andy Lutomirski , Kees Cook Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 6, 2019 at 10:35 AM Pavel Machek wrote: > > It will not: boot is now halted because systemd wants some > entropy. Everything is idle and very little interrupts are > happening. We have spinning rust, but it is idle, and thus not > generating any interrupts. Yes, but we have that problem now solved. Except on embedded platforms that have garbage CPU's without even a cycle counter. But those won't have spinning rust anyway. Yes, bad SSD's and MMC disks (that they do have) will generate timing noise too, but in the absense of a cycle counter, that noise won't be much use. Linus