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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 D35D9CD3445 for ; Fri, 8 May 2026 15:55:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To: Content-Type:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VKcA3DV9vqMoAj+PdGsNg7jOSjZ6wYE8FR26Smnim6k=; b=n9CgzBrxzY1xRZGPhkKcQ7eRFO VEptOXQK9dthB8m9uoBj+HHBnENBVfSLjQfoL6MtcELQuDYGxba/bZQ1LSY+pgmmaC1p53qSX5IDl QwRECPe0hvrsmHRn5W6v5VmYHe2z/xOT1jH50Gso2NyCvIvmgZq++qGYnh09SW2B8fvTbilgoKpN7 QZb55NoTTklVeIwSWTnhrUY+8mBvc2OytH35/TsL0pnweQoliBP+uAOL9LWOmAuRC2U0WA+V4bea3 aX/W+xS7iLqYxkbLrmGWrR1/bU6JtGiocMzRbaBYZllo8mhKOcLD2BeOL35uyrHxorowpb6pAkS6H 0/Z5V5Pw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wLNXo-00000006vDD-3F4g; Fri, 08 May 2026 15:55:16 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wLNXM-00000006v8E-0yUj for linux-arm-kernel@bombadil.infradead.org; Fri, 08 May 2026 15:54:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=MIME-Version:In-Reply-To:Content-Type: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VKcA3DV9vqMoAj+PdGsNg7jOSjZ6wYE8FR26Smnim6k=; b=JHgRN2ItiSmwyM0cmZC0Z8ab2m buVN4qVSXxdDqIbgFsuTE2cQH7HBFUGIrC1ys5/g0oO1yxFV3Lhs1dr6/Z/e8LpwnJf+5A05biL3x eA8diva3SFJNdqT6rDHogjs35tGBADlAHV3/ypQwxmjRLHfLVEc+mge8RHCbKwBXgGpc4LZCU3iZV kwCXkY8RY+Uyp9PZ7SeYcQ4RFJgGjd2x5JBZaPxgUrhlKdZs2OdyL+NTwebJFnmls3lgYf6oobBsW gpYt0UTMwCK1C1sacZ3N+HHxyVBXigLtNd6QCtOFT0qGn8tqTC8RQuB2ZDhx1+r9QXWFaKrrnSiZL cLxqYqVg==; Received: from mail-southcentralusazon11012002.outbound.protection.outlook.com ([40.93.195.2] helo=SN4PR2101CU001.outbound.protection.outlook.com) by desiato.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wLNXI-00000006ldY-39PX for linux-arm-kernel@lists.infradead.org; Fri, 08 May 2026 15:54:46 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=KwvSFHnVeVmU+vs96PDfW0q00p2+v/MtAkrIEdvLbLwkO/aWdTEHRBFriRZDiWtzAT99ajZEEOtzxBBh6SoD97J/RXZanhRU1YR6WGZ94Ce1bK5Mu6qGdVbEyMjEnQ1zt9szr23Q1TlqzIyI1t754MDglWpz2usMcQ4D3fHuXz2pCKOajRNs7jA2d7ZSY220wKRxlCo4DaakSWAxOlVX5wEa3sBWg0A05F7ojrh1G+FW9sOWQg7E5+0rdrJz/FE6t0FnOPHZIdTUbXIFCsKNCn8row/nBUMMo8GC9nqQ4oNLq5FsvnugADdrwBXUvhMSrmZ+IJ/eu3wXOBM7ZHYWiQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=VKcA3DV9vqMoAj+PdGsNg7jOSjZ6wYE8FR26Smnim6k=; b=qxuHR4Qzb6pfXWHWJXnwqHXjyd3SNXSU3GwMJyysU+dZnwD6AMexQHUtf91urqoWbuO0ssOmtF8M3PqVssRzQUOLLsnTvgKHxn/jTob1OCHSvQB7CDCdHMhZM4om3DyOqg2Z+9iSg8Gmq9YqYMxodFxawk8TCJ57VpnS1uYn5UvuoPTEfbwqI5Qr3jFLCLGBavPJ0hNesJVHop2dP1eHKws37l+vlmfLv+4/PqhKluKcC1hX5O88//sVQXF904ZXEwFUOMZpH7RjOa/nuB0F4K7W3r8eiLi4XNFAXS/N1Zk76K17Zyz73lZSPxrCDFcbH/kdkCz6pFjUIp6HLK9Ltw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=VKcA3DV9vqMoAj+PdGsNg7jOSjZ6wYE8FR26Smnim6k=; b=R+GH02+29evqKztfG547OXIoxJ8qsiLiW8XX1OiA7Q14nitT5Q3aBk8T/v9Uq9n8XyhQaJgNs+UJh4y3bRyu4OYD4YJ+kGsUOACcMyrgs9zNc2sg34cP0riEgOo33BeIoTSeWSqpJxxcAWiYdlZ9BTfZ28wpa/v2TBahpTgjq4vTfbHI7xLZmtmFAxw4BGyK1PdTjURu4dkKUr4dHw/xFB5JMwRcR0CLr/omOO9S3hp8xSboieJiOjhrk/h/pdJsQ+AcltjnqwpZAsREmI03BszvQarPQBn4he2/4KZOQHGgwmjNX5rTs33G9Ha72Sv/hI5BXeGH6bEkWLKvTQ95dg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by BY5PR12MB4178.namprd12.prod.outlook.com (2603:10b6:a03:20e::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9891.19; Fri, 8 May 2026 15:54:33 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528%5]) with mapi id 15.20.9891.017; Fri, 8 May 2026 15:54:33 +0000 Date: Fri, 8 May 2026 12:54:32 -0300 From: Jason Gunthorpe To: Pranjal Shrivastava Cc: iommu@lists.linux.dev, Jonathan Hunter , Joerg Roedel , linux-arm-kernel@lists.infradead.org, linux-tegra@vger.kernel.org, Robin Murphy , Thierry Reding , Krishna Reddy , Will Deacon , David Matlack , Pasha Tatashin , patches@lists.linux.dev, Samiullah Khawaja , Mostafa Saleh Subject: Re: [PATCH 2/9] iommu/arm-smmu-v3: Use the HW arm_smmu_cmd in cmdq selection functions Message-ID: <20260508155432.GE9254@nvidia.com> References: <0-v1-b7dc0a0d4aa0+3723d-smmu_no_cmdq_ent_jgg@nvidia.com> <2-v1-b7dc0a0d4aa0+3723d-smmu_no_cmdq_ent_jgg@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL1PR13CA0151.namprd13.prod.outlook.com (2603:10b6:208:2bd::6) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|BY5PR12MB4178:EE_ X-MS-Office365-Filtering-Correlation-Id: cb10b6b6-3651-4b94-efc1-08dead1a1928 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|22082099003|56012099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?RlMLcUYsPxqeSAjNfkVe3M6Rs80TdO1622eIddzijVRzAOzSJnKx2bqpgmXD?= =?us-ascii?Q?d6VWEAvYSp7w6wQogrS4wfwlP8WiP/01I4NyD3m7CZ1UdYZxHNx+7A31Ww51?= =?us-ascii?Q?v+vjIEqgZWE0Zy5/e2FjuQGsmUN6zqKDpSiBtMXWKKogZM+oLd8mqZ7qLlil?= =?us-ascii?Q?AnXsUGplNoBWTdvKifYwQBnGRPDZCrtBRvMRAHV2y1X6o4BCpP9AbipxGUgP?= =?us-ascii?Q?KaU01nDFO+iNleVfvt4Q/gUvR5Nh6BRsg9DW0rjevlVqw1yYGAKmu8oxX8Ap?= =?us-ascii?Q?o/7kCcshvXaVhVYOr2i4YbyIe9u7hmTWbAp5FR/0OLU+KyDwsLt0f0eiLEgz?= =?us-ascii?Q?W1ea7rVTlvnzIUSHrY2zBMdwa/rm+LSLIHPlITcD4RJ375l7iS24jj6xsRkM?= =?us-ascii?Q?1gqfRpihQW9lFSacMGwuZzjGvsu4byc1BGHPE9bR7ooWLYSUzsUqbUu+VO0o?= =?us-ascii?Q?J2XLGCsrEU6NLfGLDeO6e+7jgqGFxEEp6cFa/md/IH8Cg4MaVI6I2n3i0IO3?= =?us-ascii?Q?Yk1mzx+BQRS1ENDsG2Wr8me1Yn1RPVy4GzOgWA+27eX8GY3fz2Z+OJ0Hy4KM?= =?us-ascii?Q?XE0Aysk7LyHuXya+o/C1RgAhAMQXir4O9PIF2jDoQbs4U+FhCEqTV6unB+R7?= =?us-ascii?Q?wChajsCeJU/hM/KZOTpbiVFugKKQi4LKbmhLlXp7eoTFG6dplZIbMbstmH+c?= =?us-ascii?Q?fU0NmA2goSJuJUyCMzZVWi/cX0OUh9Ce/3Zjd8xz9wu7QCyMMOtMBfgcYNEE?= =?us-ascii?Q?lw8YFSco+M6HVLdI799T5MHiTdM6DsJWpC5+LGiulYmol6ulpm70UUoMS1LE?= =?us-ascii?Q?uZzxYJWQ4HCptg3Li19Njgf69cS6INyS/CQWn46L22OnRngIyrbtqqrWLd++?= =?us-ascii?Q?EBxdDDO7KiWWhVbEy4cWExCla4sm/ODMmCg4P0pSg/l5i9yrTXlngtaD16FW?= =?us-ascii?Q?O6p+1aIg+NXJVOjIVWI6NC4zjpWFl1dRNIUMGPSTmXX2YqdE8o0Mnr+zh11p?= =?us-ascii?Q?bZKEvCTmTOuKkdBtLpWqZ9dfitiptJ3zu7UtnMl7TuXTHneZ+5VKCGDKY75J?= =?us-ascii?Q?iW+HMug/fqXZHBYm1cTuB0TZpVBeVPCFdXkPvK9IHFhKHUhUOOxQAjEAs5B6?= =?us-ascii?Q?0Xswq67VtUuDDnRKJy8831NmH1/Hw4XnVjAUSLjiLEWEa1gfObpHW8cLeX70?= =?us-ascii?Q?0piMv7NjrlpD0rv08fpwjJ7AYRoX0g2Zd2mV6aLJsbm8YS91iXxq/WImZrRF?= =?us-ascii?Q?hYvYmGgpOrt7l7ft9Xun+yJ7jfUhybUXg/2RzVreEL/CUYYO0c7W3COkxpp7?= =?us-ascii?Q?DsnaTkew3t2EfLkQXy5WBA4XZLAGUAo4WG/IM9rkynRFaQblSZk4o118CfqO?= =?us-ascii?Q?5WqxjLwIJohw+TXuavUZPG/5jtU22uljyy98Y4GvZMDQ/Uhy/RpgmJnvOIUj?= =?us-ascii?Q?wwBgSvo4rk606JUgoSZ+/i1HaTWz/o6kfnAg4uqUDLgJbbaGFEWOgu9u+nK0?= =?us-ascii?Q?VvdusgFn2aELZ/o3f6+M5uvj1+HpTH6s82IwQCwFY9VXMOHktNrEu/OBihgr?= =?us-ascii?Q?892WeQPUVdMMjbw2hO1ZtQMmaSER/XokUud4wMYGpcqWVjFgmBsds10ye+/e?= =?us-ascii?Q?vMmmsBTs2zjAfwYbRmDFPbi9JTybD7s+pKrMC6JS7JhnRxHUoPTRBasAzE0A?= =?us-ascii?Q?4oq0TUJ8lbTN1hMlEBkj6IoEL5xzYuBb/D2yuAaoq3Wgkuwi?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: cb10b6b6-3651-4b94-efc1-08dead1a1928 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 May 2026 15:54:33.7676 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: qlNpsVMZovhv12LtxBasU/fJwrKoom/A1UPO9U9LK7lJgrVQpo36llKFNS8BW1oI X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4178 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260508_165445_144443_492D9FD5 X-CRM114-Status: GOOD ( 15.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, May 08, 2026 at 07:47:45AM +0000, Pranjal Shrivastava wrote: > On Fri, May 01, 2026 at 11:29:11AM -0300, Jason Gunthorpe wrote: > > Start removing the use of struct arm_smmu_cmdq_ent, starting at the > > lower levels of the call chain. Change the functions that determine what > > cmdq to issue the batch to into using struct arm_smmu_cmd directly. > > > > Signed-off-by: Jason Gunthorpe > > --- > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 47 ++++++++++++------- > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 8 ++-- > > .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 8 ++-- > > 3 files changed, 38 insertions(+), 25 deletions(-) > > [...] > > > index = cmds->num * CMDQ_ENT_DWORDS; > > - if (unlikely(arm_smmu_cmdq_build_cmd(&cmds->cmds[index], cmd))) { > > - dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n", > > - cmd->opcode); > > - return; > > - } > > - > > + memcpy(&cmds->cmds[index], cmd.data, sizeof(cmd.data)); > > cmds->num++; > > } > > The memcpy is a temporary step and goes way in Patch 4. To be clear patch 4 still has the memcpy: - index = cmds->num * CMDQ_ENT_DWORDS; - memcpy(&cmds->cmds[index], cmd.data, sizeof(cmd.data)); - cmds->num++; + cmds->cmds[cmds->num++] = cmd; ^^^^^^^^^^^ The compiler just builds it. The flow evolution is: Now: struct arm_smmu_cmdq_ent (stack) -> arm_smmu_cmdq_build_cmd (batch) -> memcpy (queue) Here: struct arm_smmu_cmdq_ent (stack) -> arm_smmu_cmdq_build_cmd (stack) -> memcpy (batch) -> memcpy (queue) Done: struct arm_smmu_cmd (stack) -> memcpy (batch) -> memcpy (queue) So the net result is the same before/after this series, we just carry an extra stack copy till the last patch. Thanks, Jason