From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E482026F477 for ; Tue, 29 Apr 2025 21:35:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745962521; cv=none; b=ush0P8UisGtBmnPhaGIKZQa8whUYqpjP3mcD6yfPRrh1nVk34uhNO4pUzrYMZRxNaZ3qFieWxaHuXRwNVdTCRvY31USH+8gkQ01RdJzbGkFr+hQAVwfY2rLpvEozj8nEgbTNTHPdNqf5Y96UVs9OP1evmEcOn7T/zUVPK/xMAyo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745962521; c=relaxed/simple; bh=JFtp/04AN6971ALn40g4bC8CVWUHKgt3AbR5wojCJVw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o3LNrHe4+EcV4Qrsj1L7ijwAjZVFMqu3b4jdvJ7h2+DA0GAf/Ss5VT6oPrlLyZ4rJ/JLUjbgE24w0xydArRysWxyFcy/9KV6jDnOCcO9eJeaUbyALbsRqYtUOjnUcOvc4cQ88Xq6uHA7aLWGnq46nxKKHwkwJs1zRlNQHqViKwM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=fail smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Z+Q9eO8x; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Z+Q9eO8x" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-2240aad70f2so240315ad.0 for ; Tue, 29 Apr 2025 14:35:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1745962519; x=1746567319; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=mpYoUff4tpb7ZnYnv11tnvX2uEPBYr9ascXUqkCwOTE=; b=Z+Q9eO8xeLCUuo/zkudd1dLWzxcNVjezyNiWJnWo5t2NBqP2/gndruzvGck4whmIpf 3F7EWJq3FFBl9hBOUZ6HKWb/W5eYowm7m9AfwjHzAIjH8J7WYRkOf8ga8xJEJ1B48knM 2oBZ4gSsPJkWa2hDYd/D6lHKh+M6zVIiPBOQAyFMM2Ckqjg0vonp0JuxudO6qK064UmE rrDC29NTut3AJvmXvbOdvOxVwz2dwZkVaim0E6I5vqI4ORZjMVeeN3Su0AMd/XreXuc9 33o0z31VlRCe1zcCHkLbgmelIsrI17mvFsQmbkFTH/8lfJzaJvs8i3jS6DFXNGR9vG9/ /9rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745962519; x=1746567319; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=mpYoUff4tpb7ZnYnv11tnvX2uEPBYr9ascXUqkCwOTE=; b=OlKhQ7qBBXqEhU7fG6tFgNhesqzU6X5oWwcUVSnDZD2Y+z+HEZ1gVcXmAAdmyDFMmv Fqv8Ha6lygdLSPV2QlYlGktai4G6x/z4+I8JIr47pgi8r/FjnH9SD7iyULumPSu5+EIn LZDNZjCf377IYK5ablpRKK8ChxS19vFRrdNXvW8gUstmE6qfmy8qaHqhZRhCDdoVHr/D L4VJ9GEGY6HZEMbgjmZc6mIR6Yk+EZT+C8U2lq++aZeZHZrNZC3LUa6GlcUgJ8n0vuBf LBRBbGk7NEZbbjhT6pM8x5rFf/ZMQmLZ95ilRyl3lZT1HrwOs+Cub5mgNuPGBF84M1JD iDVA== X-Forwarded-Encrypted: i=1; AJvYcCW5CPGjaQo19XNRQuCRcP72vjM9vDCuWF9VcveKMPqo6xX84abAB9JWWQ6Mcnc8F6fIEFNSeyjtCu5GQw==@vger.kernel.org X-Gm-Message-State: AOJu0Ywq8MY/qLSz7YF0YmZeffzIDkeasWrR3InTZrIsAG2tgdYO0QTK 0ZOs6S9Q/KWEtGuDIfu13TRPpRbHuc8fqMFRddO9raFZjdpNjymTa6b8+R9w7g== X-Gm-Gg: ASbGncsUhahDlCsKGHp3pQQEyHIAX1Yj1i8rTQdDTv/R4dTF/MydDBABkKs2zK60ZE9 mMdUlh3XsxdApOXkq67KPvpqAkruy/xDWok6GfnLE3j6zp4ov4xKNRWrE1foU9+bplcNKvyZmEX ixCLTkXfpt+uS3X2lUq5KNV2BoPeJYHxA9ofusMGp0GtMbKoDcOSt4qt2qj7AkuLJYpKn/Pw9Bz /HrnfraBOby7y0OCXh/vau9+29lB3QbXz0Cc0Fd6pFXEPEApcT8Ws4s7/av0M3KWRI3l5aW6ZzC NTldbs4IlsFUVlzmuW7A6tTwQfF16z5vHL4JoNI4Al3t0CTfoA01TqJow1Oy3z/+K/+3Mqoa X-Google-Smtp-Source: AGHT+IEiAc8Ows6C4iR4kgPCFAlWxuerupIBpLK64UuYqayp18C/qOLe733Vqo0YiAcQG8JFaBI7KQ== X-Received: by 2002:a17:902:f681:b0:200:97b5:dc2b with SMTP id d9443c01a7336-22df54469b2mr228275ad.15.1745962518918; Tue, 29 Apr 2025 14:35:18 -0700 (PDT) Received: from google.com (2.210.143.34.bc.googleusercontent.com. [34.143.210.2]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-30a3480f08csm42489a91.39.2025.04.29.14.35.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Apr 2025 14:35:18 -0700 (PDT) Date: Tue, 29 Apr 2025 21:35:07 +0000 From: Pranjal Shrivastava To: Nicolin Chen Cc: jgg@nvidia.com, kevin.tian@intel.com, corbet@lwn.net, will@kernel.org, bagasdotme@gmail.com, robin.murphy@arm.com, joro@8bytes.org, thierry.reding@gmail.com, vdumpa@nvidia.com, jonathanh@nvidia.com, shuah@kernel.org, jsnitsel@redhat.com, nathan@kernel.org, peterz@infradead.org, yi.l.liu@intel.com, mshavit@google.com, zhangzekun11@huawei.com, iommu@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-tegra@vger.kernel.org, linux-kselftest@vger.kernel.org, patches@lists.linux.dev, mochs@nvidia.com, alok.a.tiwari@oracle.com, vasant.hegde@amd.com Subject: Re: [PATCH v2 13/22] iommufd: Add mmap interface Message-ID: References: <7be26560c604b0cbc2fd218997b97a47e4ed11ff.1745646960.git.nicolinc@nvidia.com> Precedence: bulk X-Mailing-List: linux-tegra@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 29, 2025 at 02:05:12PM -0700, Nicolin Chen wrote: > On Tue, Apr 29, 2025 at 08:55:47PM +0000, Pranjal Shrivastava wrote: > > On Tue, Apr 29, 2025 at 01:39:09PM -0700, Nicolin Chen wrote: > > > On Tue, Apr 29, 2025 at 08:34:56PM +0000, Pranjal Shrivastava wrote: > > > > On Tue, Apr 29, 2025 at 08:24:33PM +0000, Pranjal Shrivastava wrote: > > > > > On Fri, Apr 25, 2025 at 10:58:08PM -0700, Nicolin Chen wrote: > > > > > > + struct iommufd_mmap *immap; > > > > > > + int rc; > > > > > > + > > > > > > + if (WARN_ON_ONCE(!immap_id)) > > > > > > + return -EINVAL; > > > > > > + if (base & ~PAGE_MASK) > > > > > > + return -EINVAL; > > > > > > + if (!size || size & ~PAGE_MASK) > > > > > > + return -EINVAL; > > > > > > + > > > > > > + immap = kzalloc(sizeof(*immap), GFP_KERNEL); > > > > > > + if (!immap) > > > > > > + return -ENOMEM; > > > > > > + immap->pfn_start = base >> PAGE_SHIFT; > > > > > > + immap->pfn_end = immap->pfn_start + (size >> PAGE_SHIFT) - 1; > > > > > > + > > > > > > + rc = mtree_alloc_range(&ictx->mt_mmap, immap_id, immap, sizeof(immap), > > > > > > > > > > I believe this should be sizeof(*immap) ? > > > > > > > > Ugh, Sorry, shouldn't this be size >> PAGE_SHIFT (num_indices to alloc) ? > > > > > > mtree_load() returns a "struct iommufd_map *" pointer. > > > > I'm not talking about mtree_load. I meant mtree_alloc_range takes in a > > "size" parameter, which is being passed as sizeof(imap) in this patch. > > IIUC, the mtree_alloc_range, via mas_empty_area, gets a range that is > > sufficient for the given "size". > > > > Now in this case, "size" would be the no. of pfns which are mmap-able. > > By passing sizeof(immap), we're simply reserving sizeof(ptr) i.e. 8 pfns > > for a 64-bit machine. Whereas we really, just want to reserve a range > > for size >> PAGE_SHIFT pfns. > > But we are not storing pfns but the immap pointer.. Ohh... so we are storing the raw pointer in the mtree.. I got confused with the `LONG_MAX >> PAGE_SHIFT`.. Sorry about the confusion! > > Nicolin