From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@kernel.org>
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=-3.8 required=3.0 tests=BAYES_00,
	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 4F4E9C4320A
	for <linux-kernel@archiver.kernel.org>; Tue, 31 Aug 2021 23:05:08 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id 2DC3160041
	for <linux-kernel@archiver.kernel.org>; Tue, 31 Aug 2021 23:05:08 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S241171AbhHaXGC (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Tue, 31 Aug 2021 19:06:02 -0400
Received: from rosenzweig.io ([138.197.143.207]:44836 "EHLO rosenzweig.io"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S240560AbhHaXGB (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 31 Aug 2021 19:06:01 -0400
Date:   Tue, 31 Aug 2021 17:32:07 -0400
From:   Alyssa Rosenzweig <alyssa@rosenzweig.io>
To:     Sven Peter <sven@svenpeter.dev>
Cc:     iommu@lists.linux-foundation.org, Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Arnd Bergmann <arnd@kernel.org>,
        Mohamed Mediouni <mohamed.mediouni@caramail.com>,
        Alexander Graf <graf@amazon.com>,
        Hector Martin <marcan@marcan.st>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/8] Support IOMMU page sizes larger than the CPU page
 size
Message-ID: <YS6f17iFVq9wYPFN@sunset>
References: <20210828153642.19396-1-sven@svenpeter.dev>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210828153642.19396-1-sven@svenpeter.dev>
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> Some background: On the Apple M1 the IOMMUs are hardwired to only support 16 KB pages.
> We'd still like to boot Linux with 4KB pages though because that's what most distros
> ship these days. This patch series adds support for that setup to the IOMMU DMA API.

This isn't just a distro issue -- efficient x86_64 emulation will rely
on 4KB as well (Rosetta, FEX, ...). Telling distros to use 16KB kernels
for Apple parts is just kicking the can down the road -- we want this
series even for kernels we build ourselves.