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 44F9FC4345F for ; Wed, 17 Apr 2024 15:14:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=KIBeJmo4U8ABJe/jCWDNB0J7BD5Cxexm2wq/vcVROEc=; b=juDA7wDFKaJD5c xP6iFlldMBuG/2FqN9Vu7UetoREa+nsutkJxI5nm8GhwLecuggtMXzI8pMNycLP1xQwlSXYnQ/J+9 QOUVY2dy2Znkr2+p649sRZmn0Q9/F7FOq48+hKI7gTMFNrnHnktiy4TSwSYcdxdCDbFsTwbxQeCel CvUoMbcVtelsbRiuRu2Vn83Vqy4GSpEgXwfTqTL/konBn9SZFRTm0i98j+azLlWzHg93EvHAYPzV+ 5YZ7peNhzji5b2bTQzI/RR8Xu6wneBCFksU/vSpFJTX8CRjG2TUlLK66fypy1geM+uE/LySr347cG KjUbJjM/SK+aPAQ6KCpA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx6z1-0000000GWuk-1FA0; Wed, 17 Apr 2024 15:13:59 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx6yx-0000000GWt8-0xEX for linux-arm-kernel@lists.infradead.org; Wed, 17 Apr 2024 15:13:56 +0000 Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4VKPWr6YZKz6H6yd; Wed, 17 Apr 2024 23:11:52 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 3D59E1406AC; Wed, 17 Apr 2024 23:13:53 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (7.191.163.240) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Wed, 17 Apr 2024 16:13:52 +0100 Received: from lhrpeml500005.china.huawei.com ([7.191.163.240]) by lhrpeml500005.china.huawei.com ([7.191.163.240]) with mapi id 15.01.2507.035; Wed, 17 Apr 2024 16:13:52 +0100 From: Shameerali Kolothum Thodi To: Jason Gunthorpe CC: Nicolin Chen , "will@kernel.org" , "robin.murphy@arm.com" , "joro@8bytes.org" , "thierry.reding@gmail.com" , "vdumpa@nvidia.com" , "jonathanh@nvidia.com" , "linux-kernel@vger.kernel.org" , "iommu@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-tegra@vger.kernel.org" , Jerry Snitselaar Subject: RE: [PATCH v5 0/6] Add Tegra241 (Grace) CMDQV Support (part 1/2) Thread-Topic: [PATCH v5 0/6] Add Tegra241 (Grace) CMDQV Support (part 1/2) Thread-Index: AQHajVTpda5PtrGZ80+YonTPgO6cRrFphU4AgAKXr6CAADwLgIAAP9dA Date: Wed, 17 Apr 2024 15:13:52 +0000 Message-ID: <85e7752fed7444ea8611dbc5be288044@huawei.com> References: <20240415171426.GF3637727@nvidia.com> <20240417122445.GO3637727@nvidia.com> In-Reply-To: <20240417122445.GO3637727@nvidia.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.202.227.28] MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240417_081355_681413_C7CDC7E8 X-CRM114-Status: GOOD ( 21.69 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > -----Original Message----- > From: Jason Gunthorpe > Sent: Wednesday, April 17, 2024 1:25 PM > To: Shameerali Kolothum Thodi > Cc: Nicolin Chen ; will@kernel.org; > robin.murphy@arm.com; joro@8bytes.org; thierry.reding@gmail.com; > vdumpa@nvidia.com; jonathanh@nvidia.com; linux-kernel@vger.kernel.org; > iommu@lists.linux.dev; linux-arm-kernel@lists.infradead.org; linux- > tegra@vger.kernel.org; Jerry Snitselaar > Subject: Re: [PATCH v5 0/6] Add Tegra241 (Grace) CMDQV Support (part 1/2) > > On Wed, Apr 17, 2024 at 08:01:10AM +0000, Shameerali Kolothum Thodi wrote: > > We do have plans to revive the SMMUv3 ECMDQ series posted a while back[0] > > and looking at this series, I am just wondering whether it makes sense to have > > a similar one with ECMDQ as well? I see that the NVIDIA VCMDQ has a special > bit > > to restrict the commands that can be issued from user space. If we end up > assigning > > a ECMDQ to user space, is there any potential risk in doing so? > > I think there is some risk/trouble, ECMDQ needs some enhancement > before it can be really safe to use from less privileged software, and > it wasn't designed to have an isolated doorbell page either. > > > Not clear to me what are the major concerns here and maybe we can come up > with > > something to address that in kernel. > > I haven't looked deeply but my impression has been the ECMDQ is not > workable to support virtualization. At a minimum it has no way to > constrain the command flow to a VMID and to do VSID -> PSID > translation. Ok. That makes sense. > > I suggest you talk directly to ARM on this if you are interested in > this. > Sure. Will check. Thanks, Shameer _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel