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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D710DC48BE8 for ; Fri, 18 Jun 2021 14:32:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8F2161222 for ; Fri, 18 Jun 2021 14:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234348AbhFROea (ORCPT ); Fri, 18 Jun 2021 10:34:30 -0400 Received: from verein.lst.de ([213.95.11.211]:35190 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233642AbhFROe1 (ORCPT ); Fri, 18 Jun 2021 10:34:27 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 64B2C68D08; Fri, 18 Jun 2021 16:32:12 +0200 (CEST) Date: Fri, 18 Jun 2021 16:32:12 +0200 From: Christoph Hellwig To: Tom Lendacky Cc: Claire Chang , Stefano Stabellini , Rob Herring , mpe@ellerman.id.au, Joerg Roedel , Will Deacon , Frank Rowand , Konrad Rzeszutek Wilk , boris.ostrovsky@oracle.com, jgross@suse.com, Christoph Hellwig , Marek Szyprowski , benh@kernel.crashing.org, paulus@samba.org, "list@263.net:IOMMU DRIVERS" , Robin Murphy , grant.likely@arm.com, xypron.glpk@gmx.de, Thierry Reding , mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org, Greg KH , Saravana Kannan , "Rafael J . Wysocki" , heikki.krogerus@linux.intel.com, Andy Shevchenko , Randy Dunlap , Dan Williams , Bartosz Golaszewski , linux-devicetree , lkml , linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xenproject.org, Nicolas Boichat , Jim Quinlan , Tomasz Figa , bskeggs@redhat.com, Bjorn Helgaas , chris@chris-wilson.co.uk, Daniel Vetter , airlied@linux.ie, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com, Jianxiong Gao , joonas.lahtinen@linux.intel.com, linux-pci@vger.kernel.org, maarten.lankhorst@linux.intel.com, matthew.auld@intel.com, rodrigo.vivi@intel.com, thomas.hellstrom@linux.intel.com Subject: Re: [PATCH v13 01/12] swiotlb: Refactor swiotlb init functions Message-ID: <20210618143212.GA19284@lst.de> References: <20210617062635.1660944-1-tientzu@chromium.org> <20210617062635.1660944-2-tientzu@chromium.org> <741a34cc-547c-984d-8af4-2f309880acfa@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <741a34cc-547c-984d-8af4-2f309880acfa@amd.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 18, 2021 at 09:09:17AM -0500, Tom Lendacky wrote: > > swiotlb_init_with_tbl uses memblock_alloc to allocate the io_tlb_mem > > and memblock_alloc[1] will do memset in memblock_alloc_try_nid[2], so > > swiotlb_init_with_tbl is also good. > > I'm happy to add the memset in swiotlb_init_io_tlb_mem if you think > > it's clearer and safer. > > On x86, if the memset is done before set_memory_decrypted() and memory > encryption is active, then the memory will look like ciphertext afterwards > and not be zeroes. If zeroed memory is required, then a memset must be > done after the set_memory_decrypted() calls. Which should be fine - we don't care that the memory is cleared to 0, just that it doesn't leak other data. Maybe a comment would be useful, though,