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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0C800CAC5BB for ; Wed, 1 Oct 2025 13:48:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v3xBC-0007YR-M5; Wed, 01 Oct 2025 09:47:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v3xAu-0007WZ-PE; Wed, 01 Oct 2025 09:47:20 -0400 Received: from [185.176.79.56] (helo=frasgout.his.huawei.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v3xAk-0003zq-Bv; Wed, 01 Oct 2025 09:47:20 -0400 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4ccGNg62rqz6M4Qg; Wed, 1 Oct 2025 21:43:47 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 4336F1404FE; Wed, 1 Oct 2025 21:46:56 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 1 Oct 2025 14:46:55 +0100 Date: Wed, 1 Oct 2025 14:46:53 +0100 To: Shameer Kolothum CC: , , , , , , , , , , , , , , , , Subject: Re: [PATCH v4 23/27] hw/arm/smmuv3-accel: Add property to specify OAS bits Message-ID: <20251001144653.0000456b@huawei.com> In-Reply-To: <20250929133643.38961-24-skolothumtho@nvidia.com> References: <20250929133643.38961-1-skolothumtho@nvidia.com> <20250929133643.38961-24-skolothumtho@nvidia.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.203.177.15] X-ClientProxiedBy: lhrpeml100010.china.huawei.com (7.191.174.197) To dubpeml100005.china.huawei.com (7.214.146.113) X-Host-Lookup-Failed: Reverse DNS lookup failed for 185.176.79.56 (deferred) Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 29 Sep 2025 14:36:39 +0100 Shameer Kolothum wrote: > QEMU SMMUv3 currently sets the output address size (OAS) to 44 bits. With > accelerator mode enabled, a guest device may use SVA where CPU page tables > are shared with SMMUv3, requiring OAS at least equal to the CPU OAS. Add > a user option to set this. > > Note: Linux kernel docs currently state the OAS field in the IDR register > is not meaningful for users. But looks like we need this information. So is there a kernel documentation fix pending? :) Mind you I think we should ensure this is true anyway in QEMU as some other OS might do weird things if it's not. Maybe we should just raise the default QEMU uses (with compat stuff for older qemu) and not worry about an exposed control for this? > > Signed-off-by: Shameer Kolothum > --- > hw/arm/smmuv3-accel.c | 15 +++++++++++++++ > hw/arm/smmuv3-internal.h | 3 ++- > hw/arm/smmuv3.c | 15 ++++++++++++++- > include/hw/arm/smmuv3.h | 1 + > 4 files changed, 32 insertions(+), 2 deletions(-) > > diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c > index eee54316bf..ba37d690ad 100644 > --- a/hw/arm/smmuv3-accel.c > +++ b/hw/arm/smmuv3-accel.c > @@ -86,6 +86,17 @@ smmuv3_accel_check_hw_compatible(SMMUv3State *s, > return false; > } > > + /* > + * ToDo: OAS is not something Linux kernel doc says meaningful for user. > + * But looks like OAS needs to be compatibe for accelerator support. Please spell check this too.. > + * check. > + */