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 A6C5DC02192 for ; Wed, 5 Feb 2025 23:17:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C5B26B0088; Wed, 5 Feb 2025 18:17:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 175F86B0093; Wed, 5 Feb 2025 18:17:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 03CF66B0095; Wed, 5 Feb 2025 18:17:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id DB9E16B0088 for ; Wed, 5 Feb 2025 18:17:34 -0500 (EST) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 8A09C4A2EB for ; Wed, 5 Feb 2025 23:17:34 +0000 (UTC) X-FDA: 83087454828.17.352A42B Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf29.hostedemail.com (Postfix) with ESMTP id ADD6D120008 for ; Wed, 5 Feb 2025 23:17:31 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=cC+0IT9z; spf=none (imf29.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738797452; 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=Eo8iddA5F3+GfWnUXk00TmgLrVbfJuqGlTFhAHUQxOU=; b=yNOq41VlNxQNUaxJaaP6Cx6pFsY+vsC4i08/OZz98hVLjs5u2mtePoLhDfCt4pWGLb15MY 3aJ6rC7qC5ZlKfkfN9nMH5vA/JGpXHMcdPq6x/SOxysJQVRx2GbNBfnoYCoThJt/maxUlJ PnX9LwqJF04vYpkmlfC5OJW2wwVAJT4= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=cC+0IT9z; spf=none (imf29.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738797452; a=rsa-sha256; cv=none; b=iVxklOwHuNEL8bKnSJFb7i6pCanITaPycBBjIZg0gXApVF9COoDLPwDWyUthcz3bf4flfb JHwDQzSL5+GOdBs6gAmCH4ZL31nQzqh724FxIwpQJv1Pjb+ZQd8+UODAi46HDTs1Whp5jT sRhe8xylzhKRAfHjx9noqKzVCsMUsqI= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Eo8iddA5F3+GfWnUXk00TmgLrVbfJuqGlTFhAHUQxOU=; b=cC+0IT9zSR753XY+TILiRLEpHu 954DArINS0Z/g3l1UXY7LvAmL+Ca8JC8U1PlzIYkR5BlqmYQRo4uRq69R8yhGc2zN3XLnsEVQ1b34 P/+2S6NBylkv//Nz5ywwl3HJ6snDBCCRdGFJ6EPYRBj6TtzKStzhc54X+Y3/o4nfBGNmm1DzTdKqH XKuBS6DaN9TRjKfup4VY1Ykl0VT62FDJ1B0qUPqFW8uVEr5Znwq1Y+4VeJprFzdtmqVRSUgAGCMRd jSieY1LguqWUNEOwJZfcIrRQqw4kXEWlmKiMsToIY+xg9cyz0cjWE0F+H8LkGkACUFPGLWbdjBJl+ gVDEp1Qw==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tfody-000000059Mt-2d7z; Wed, 05 Feb 2025 23:17:18 +0000 Date: Wed, 5 Feb 2025 23:17:18 +0000 From: Matthew Wilcox To: Jason Gunthorpe Cc: David Hildenbrand , Asahi Lina , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Jann Horn , Paolo Bonzini , Danilo Krummrich , Wedson Almeida Filho , Valentin Obst , Andrew Morton , linux-mm@kvack.org, airlied@redhat.com, Abdiel Janulgue , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev Subject: Re: [PATCH 0/6] rust: page: Support borrowing `struct page` and physaddr conversion Message-ID: References: <20250202-rust-page-v1-0-e3170d7fe55e@asahilina.net> <1eaf66ba-b2d3-448f-938b-913f17ca98a4@redhat.com> <20250204183933.GJ2296753@ziepe.ca> <1d379007-97c3-4bb9-93da-1a828f955fc4@redhat.com> <20250204202656.GL2296753@ziepe.ca> <08ce9562-9ded-4d95-a495-b60f90d75490@redhat.com> <20250204204947.GM2296753@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250204204947.GM2296753@ziepe.ca> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: ADD6D120008 X-Stat-Signature: 5ky6rdhpse863bfe6z3n6qd7zdz17399 X-Rspam-User: X-HE-Tag: 1738797451-416212 X-HE-Meta: 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 BJqilQdL dRge3VyRXZY9FxLwK4Qi9/YpQiZ5dLVIcUmWLZOCDTHcMdbFYk1PVuBW04adurxCLMUVIvFCinoR4U9kY+gXOC0vP/PLXV4P81uTcsRZjaELfJTZydtoX/fBcnNaJ+i+y8DIWfzYer8Z8mOI9FCgxkjhoF8r74KXw64xUjg6L/LndqPqDym5cgtVp8PWYeevB+TDyZaojZ/4I2zt9POPg21YorbJaipnkOqjjHSU0tvKanAQpjra1JZ31Do5yErEgCuomqV1qsttTcGK0KVBhbrogFJnH1ISMV9rTp0mppNNw2J0= X-Bogosity: Unsure, tests=bogofilter, spamicity=0.500000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Feb 04, 2025 at 04:49:47PM -0400, Jason Gunthorpe wrote: > The phys_to_virt() I mean is on the page table pages themselves, not > on a leaf. > > All page table pages came from alloc_pages_node() and you'd do > virt_to_phys() to stick them into a next-table PTE, then > phys_to_virt() to bring them back: > > phys_to_virt(virt_to_phys(page_address(alloc_pages_node()))) > > Effectively. except for s390 & ppc where the page table can be smaller than PAGE_SIZE, so you really only have a physical address that can be converted to a virtual address.