From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (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 2222726FA42 for ; Tue, 29 Apr 2025 21:35:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745962521; cv=none; b=NLmhfIRT8ekkFwgoo5/TYs9xQYzNb/v3T1h3caQatCJ5hO82IlFHtHrT4fY3WFS4CmhuyTXxh1sHGQP50bCLUg456n+xJRuqdbVJg9rW5HQcoI/gOHrpjgWMEoYpNRyp8QZ9Q2s7xIwPJ9bk6fkaUYfisALpxnDJQLTg7LSsUtg= 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=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=4AfRXEFl; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="4AfRXEFl" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2240aad70f2so240445ad.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=lists.linux.dev; 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=4AfRXEFlmjF4rs+0nBURTHheo/Y+qXkS99Xu93tztwDoC6TFF3f4nPY4+wMeIH+Vsh enTUCxhPlnv/ENz0yucRvLayJpDj7zPdTODe6+mgroBMNola8L7iwtJ15kn8BEnhJJAw TiDtnwEdKWwK6TsP6ema4MJbj/YGvUbQ7koMGOtidXoZdZDneC4tIE0BSocnZXv7NYPd rZ/G6BroCkVlHACWP5sPBBF7lj0nfmHjqUK+rCqTUpUfHtEzQ4h3dNGTAUmRdMB18sSC FHVVNmBBTrnaXE36NApIGCsAvbyWAACNYOwl9pG3pM/2MuCVqse/DU2k1uzWSLSl182I wv6w== 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=ITz8W9C8rhlCzE9bSI3UF1ww3dtyWniW0jX0tunt1Q8CFIm5U1UX8zLL4G69RSh/Hl chGxaV1Ko1sAvuTPxo8b/2t2dgUZ7vxojtVMz0c2F7c4Zz8y/5X5LbPrNEQ8pDyNdBuP oEHAQPBuxnycwfPjujhVFBoTEChZk9onHE1e+yQlr9brKHDTMb/itP+UGbbUKkEKEHaF ZtdIv25yS8zbMxwbVxpQsLlnarFII9FnWL7IaLDaCWNaQR3SwPJfnfqIBLd4Mw0YDQWD FvrRaWBfsP22Tar93eqizuhVZH5M0CnKO216f195cV20h2nisv95RpN/DL9Mg8hBpyzk fYqw== X-Forwarded-Encrypted: i=1; AJvYcCXyVeU+t6mOvMV+2Mfxmk7hOsMrTz5ORHYfGi8bUSDX7s51NJWNJWQW0imzg47Hu7DBBkI0Tu+5@lists.linux.dev X-Gm-Message-State: AOJu0Yw8NbKQa7qCSTmiBRmYgQPY3FJqtZtkl59Z3BGaCBlLlXoLRA94 Vi2BEOKi0X/EnmF0snPise3Lz6LJeZZYnKB3kuYFUxHUtYJeZiQIcVht8NsjXA== X-Gm-Gg: ASbGncuQE6NuM2ahCWL4LHPntnWQAPdUTRhqj7C8PKGTog7gXIvXpDVr4aJaw1XJBhF jEC557hWgegxBk7TqeuJm5urOd8hKQPY04Jr+b8H6kBN3NybJ2kQIbMki79StaNJYKtl+bRXEOB doKb9tewnVu8dsDMeWh7EBdVOZHQkmweVsM1Bx5A+f0dd/MSwuENG4usIyLlB8wSm5EqNE5f3zK iUcHSbaghqvuKBNI/97ABT3W0IatbEohxH8wcqz+7v0eRc5InaSL38JszioClSaEoJO7KXzR44P B480FFFYpacL7J1UN87VJ6Efgkq1WrrTrLDiJGlDFLMHRVOmIdnoeAZJta+OttcRM1vFtBIL 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: patches@lists.linux.dev 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