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 BBE32C77B7A for ; Wed, 17 May 2023 09:26:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2C44D900004; Wed, 17 May 2023 05:26:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 27484900003; Wed, 17 May 2023 05:26:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 163AC900004; Wed, 17 May 2023 05:26:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 081DF900003 for ; Wed, 17 May 2023 05:26:27 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id D027EA04E1 for ; Wed, 17 May 2023 09:26:26 +0000 (UTC) X-FDA: 80799216372.10.30D40EF Received: from mail-vs1-f51.google.com (mail-vs1-f51.google.com [209.85.217.51]) by imf09.hostedemail.com (Postfix) with ESMTP id 20365140007 for ; Wed, 17 May 2023 09:26:24 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=RTGq+QqJ; spf=pass (imf09.hostedemail.com: domain of sumit.garg@linaro.org designates 209.85.217.51 as permitted sender) smtp.mailfrom=sumit.garg@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1684315585; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=463+jZc1SwwU5dLnkJuI6XEsKfsLcH9JXONEkR0chgc=; b=JWdsBCPH3pUcHzOdQ6mwk9coeIFHk9oIt+ymIB5LEyliCx7C3PI8kZJfPnWVuLw5kryKC/ cFLplrhEqwCq4ksERXrUcE/iHuaTdKrXg7h0LIGYxXa/zU99wck2Joz6nwpx7Z3cENhCz/ WpiL9GQSwdM23mFIvtV6qq8kl4j9CVA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1684315585; a=rsa-sha256; cv=none; b=FXW2rRyIZ4juvtJkalNXgvV4qRNeJz75g6tE4d1d1kIDYz/L2dh3U5jacMh69y6s8vg3Il Uxvkrvo6ATTLlrqpi5Qyacpcegd2zyYP/fOCNkTuQymWtw6OiXkIVwUKH1YvBeocU2liK6 Y8AswEb3tBtu0fUiya8ezyQzgH0156o= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=RTGq+QqJ; spf=pass (imf09.hostedemail.com: domain of sumit.garg@linaro.org designates 209.85.217.51 as permitted sender) smtp.mailfrom=sumit.garg@linaro.org; dmarc=pass (policy=none) header.from=linaro.org Received: by mail-vs1-f51.google.com with SMTP id ada2fe7eead31-43656c7c686so144034137.0 for ; Wed, 17 May 2023 02:26:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1684315584; x=1686907584; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=463+jZc1SwwU5dLnkJuI6XEsKfsLcH9JXONEkR0chgc=; b=RTGq+QqJxYy7xeDFAit4vzaKELbLA36E0UzlE08wsYK6eLKFfbF2GkFnwLhz1m8eSQ VH8Ub22Ag9n5Z4MAdl2pmlAYpKCeZ2Y87GWNObQmYeAWwsZo/Ww2yljN54aRFCZR3jzh ManuXTZEbtdQH5i4shA/+zZZ6Fobi7suRF6XqWLFHnotR4ClCMIoD1CcybnDia3xqgKI ug4xMNdIYYKwR5CvQtLdK7QFw+HmMV+L3zh56RgjtfdbbEFsrddyx9aGaVfC8v9EdI1G 6XdlCJOBA3YOXBngguDulzJ1HcRzO92hi7lU9+wXuSz5FGfFnxPidV40yb34KQO6Xa/r CyUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684315584; x=1686907584; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=463+jZc1SwwU5dLnkJuI6XEsKfsLcH9JXONEkR0chgc=; b=biR8WpZMcV8fzxUHy1GlS8rBZt7OttYKNb9QbYD1+8C2EuxNdHyk0NrUd5dT9mFQhn lHog6ya74TR+6aM4pBSF5l1A6ZaLp82xRbGbWHrnCRhVf/DmvyFuoT7c/Dp5PPQ7Zx61 JGqNs5cPiTM7/RAUCmY24Lha2QwOm4WUNnbGwz8rma73Bpd4ZJiv8ZsudkjZpvk/WzpH UQV+r3Zg3Gc15Akt4PobVGpzzHE7NYGrtLLs0uk0mjh+OKqM5lJ5QKvYU1mRl0d7EIge oNJ01QD/fjT29wXPqksl72yLUjM7uuxTLEcA4ys0UHwVgNzZPPxZzmFJjc+PJ3tZ2lDU Y5dQ== X-Gm-Message-State: AC+VfDwQzX+RhZ16m3e1ztuAqLa144hmGv7Mk67EghQzd2LBpVNTUNnw WYRTDCtkeT7cImPvA9aZjKS13i0peS9qxAZzRpbq7Q== X-Google-Smtp-Source: ACHHUZ7PlEf9sZpsVL8yIFKgry46KtQDWkG5cMNReUJNl/yajmdY8zfYgicaCu9oahkhryydSeLIJRfBwHvVgdFTVqg= X-Received: by 2002:a67:e3c3:0:b0:436:367:4ac0 with SMTP id k3-20020a67e3c3000000b0043603674ac0mr13539923vsm.19.1684315584095; Wed, 17 May 2023 02:26:24 -0700 (PDT) MIME-Version: 1.0 References: <20230517031856.19660-1-xiaoming.ding@mediatek.com> In-Reply-To: From: Sumit Garg Date: Wed, 17 May 2023 14:56:13 +0530 Message-ID: Subject: Re: [PATCH] tee: add FOLL_LONGTERM for CMA case when alloc shm To: Christoph Hellwig Cc: Xiaoming Ding , Jens Wiklander , Matthias Brugger , AngeloGioacchino Del Regno , op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, fei.xu@mediatek.com, srv_heupstream@mediatek.com, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 20365140007 X-Stat-Signature: wfyo5getewpfwfyemu73b3ksi3x3oeka X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1684315584-257249 X-HE-Meta: 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 spyB7N4t xa/7It/ypQXp3UlhO7mD2FHd/K2DTF6YgjuPrtKX31WRDU7w0JEGPYTdXZ914nz/NMwBd0Q+PaMtTIHLbD1X/jmUS8eSGTI1SQFUnBa3U5LuwgT6cgBUjhs+GfLZUbenOOqnsiRQB4UMGAX4nSrric1wxt4Yh89Qfa/83DBNzw3B0Bo/75Yyzu6KtMjivCzprJz0awWOKbbqYpFXM0CydxXXBZ7tLOgQCXlcZpjAGgofMmYaJivz/qxpOsJIdw4AgQ18TF5YHBrxCJ+rhy5WRHQFcYNFBXvZc6Ti1bK6/lIba406zfbhiBNrx5LHNyAfpdZ99fe+sDO9DJAeqH+3PFw48l5IqgAiwpEiwGAQSBOKGalf6ucGSLdj+QEC5/N7A0m0oyZ/3o8PPHvdKz6u9DtauBQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 17 May 2023 at 13:38, Christoph Hellwig wrote: > > On Wed, May 17, 2023 at 01:22:51PM +0530, Sumit Garg wrote: > > > > +#if IS_ENABLED(CONFIG_CMA) > > > > + page_flag |= FOLL_LONGTERM; > > > > +#endif > > > > if (flags & TEE_SHM_USER_MAPPED) > > > > > > If this mapping is long live it should always use FOLL_LONGTERM. > > > > It depends on the userspace application needs. However, I think it > > should be safe to use FOLL_LONGTERM by default to serve cases like > > secure media playback. > > long term is defined as won't automatically go away during the same > syscall. Do you mean a pinned user-space page can be paged out automatically? The documentation [1] isn't very helpful here either since it talks about "short term" vs "long term" in abstract terms. Just FYI, the underlying use-case for TEE registered shared memory is that the references to pinned pages are provided to TEE implementation to operate upon. This can happen over multiple syscalls and we want the pinned pages to be always in RAM as otherwise the physical addresses may change if they are paged out in between. If this is only supported reliably with a long term flag then this patch should be tagged as a fix and requires stable backports. [1] Documentation/core-api/pin_user_pages.rst -Sumit