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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94EA9C433F5 for ; Tue, 26 Apr 2022 19:25:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 066CF6B0074; Tue, 26 Apr 2022 15:25:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 015F06B0075; Tue, 26 Apr 2022 15:25:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DF8B06B0078; Tue, 26 Apr 2022 15:25:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id D1E046B0074 for ; Tue, 26 Apr 2022 15:25:23 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A97F727659 for ; Tue, 26 Apr 2022 19:25:23 +0000 (UTC) X-FDA: 79400008926.06.8DFA3FA Received: from mail-vk1-f175.google.com (mail-vk1-f175.google.com [209.85.221.175]) by imf27.hostedemail.com (Postfix) with ESMTP id DFD184004D for ; Tue, 26 Apr 2022 19:25:21 +0000 (UTC) Received: by mail-vk1-f175.google.com with SMTP id s68so9196287vke.6 for ; Tue, 26 Apr 2022 12:25:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+ld2m+Tr2wCraXrPHkNnJwd1zustAkkc/bhAPe4XbRg=; b=GyacA6VeALD/uJDRFa2jaC/Zr+3FtN14LDpS8pZyXeFnBsmQVQZRqppx2AAuC7ZeXg 7hl7LJpfvPcnqxtp/w7ZgJAVPCHRFhJhn5fcSm4HLTuw3DB8Y9l/wo6wGrdWW9RbeTEB 9oywvBcAJYKjP0nu770JNkLpAEFccOm4yh50o9hTVt8qN5zpYCDViPgmbQc7UJD24eCJ 59WMf+q+9ADCQBaaYUfjWwW9kbbjoSqnU6ttQB3q1lkazx5/Xy94OQH3oLT55bVnJZ18 0n8oOc/fRSMVL3OUMwl+6zyX2+lNvOHvajSXrOcwr/JPCM5p22T7p2w7nQUbXo5UI6bs jIOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+ld2m+Tr2wCraXrPHkNnJwd1zustAkkc/bhAPe4XbRg=; b=C827Fty2lM/p/GANMSq0RJkw8DVoegkHOG7vSRc2PCYpxn5/XOcje5kg/4Ra6zXC2N XlUdtOKkDeP9etVJOZo96kVwPdul+UpNeDiZBIw0xy0EUWgNkCdQRYFZOpiJQZn5C+7c OPpjG4ZXUYoyU/9M87KmhADeNt9vx8nSmJbm0FScd1c0nbOcOVjjbV4hMtq2RDu1m2P3 UgGlv0W1UEunucYj/Kunqc3EGinOOj9PD/lczW/qBggFsO5kOPkH+bA9ETjdTALAFd2K zZU7qfZCYNzZyrZlfmr3SjrCZx0xkY9LpFuFf33FXbUJDf+Di+N+jQ8mPdKgyiwSyJkZ S3aw== X-Gm-Message-State: AOAM531Jw83m+F+KsQHCHQu1b2GNrOYDUcglPW6QjWwyg+8pdnmzoj4n 6KLRbTcPG89uokWrzDwsUbDw+x9QBuCu2aeTzavVPA== X-Google-Smtp-Source: ABdhPJxuhH8SGpFrZUKQf0A2ZZrZkBE1uzMw0xwmn4pyRxsjGO35+KH2SfB0vROBtOZ5B4UNBNGUJDm1lnBYxFLRfOQ= X-Received: by 2002:a1f:2615:0:b0:345:21a9:e606 with SMTP id m21-20020a1f2615000000b0034521a9e606mr7378921vkm.22.1651001122210; Tue, 26 Apr 2022 12:25:22 -0700 (PDT) MIME-Version: 1.0 References: <20220425163451.3818838-1-juew@google.com> <8eceffc0-01e8-2a55-6eb9-b26faa9e3caf@intel.com> In-Reply-To: <8eceffc0-01e8-2a55-6eb9-b26faa9e3caf@intel.com> From: Jue Wang Date: Tue, 26 Apr 2022 12:25:11 -0700 Message-ID: Subject: Re: [RFC] Expose a memory poison detector ioctl to user space. To: Dave Hansen Cc: Naoya Horiguchi , Tony Luck , Dave Hansen , Jiaqi Yan , Greg Thelen , Mina Almasry , linux-mm@kvack.org, Sean Christopherson Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 3j4a1edrb4wnqmfip4szc6frcku4b85a Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=GyacA6Ve; spf=pass (imf27.hostedemail.com: domain of juew@google.com designates 209.85.221.175 as permitted sender) smtp.mailfrom=juew@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DFD184004D X-HE-Tag: 1651001121-905998 X-Bogosity: Ham, tests=bogofilter, spamicity=0.091654, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 26, 2022 at 11:18 AM Dave Hansen wrote: > > On 4/26/22 11:02, Jue Wang wrote: > >>> Are there any other physical addresses which are RAM but should not have > >>> the detector used on them? > > In theory, if some physical address range are never / very rarely > > accessed, they can be exempted. > > How would userspace know to exempt them? User space won't know, if kernel has this knowledge, I suppose an appropriate error code can be returned to inform user space this address region should be exempted from future scanning? >