From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E6837263F30 for ; Mon, 29 Sep 2025 21:17:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759180677; cv=none; b=NeoPQFP/CbWlOCBxJWO533lG4CTiAQtoDAqritVoMHeY1QJsRhvG8m1eYDqZB4OcEERMXO3WG91k6QcvCTTbPPrbzJPZl5DlTTAZX7GpJzBwUk7pkFzyUPwehwcsqTuG2aE6uR0hz63/HISSWPrTDbRmPfTZKB0HkztiF5P4SYs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759180677; c=relaxed/simple; bh=pkxsk78IHog0vv+IBSdn+sUVFtS8RfXXuKpUO43hniM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Qmn81pnFdMHwK1qch/azVJ1j4A9j+zPUoq71P+mtCgJRZws6uBC+08scXPorGMxNK4pzcorlzRsaem+beGfOiv7bCkL+DvBUx+MpDslMS7BQzlk18EeeSQ2m7+h2WT0K97YhbmHhHvMk+//0uT1pa4q5jcYasMzgeg2CxoHkV4Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=AoVB7n49; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="AoVB7n49" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759180674; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tBEzt7vDi7cQon8pe4PxgzLkANUC3bHfRN0ntBJldU8=; b=AoVB7n49DgHSo37MjaQllW4eGuNjjEw5pl3xaRFAwSHzydcdRsI6sMss4RD3X8SS9MbZgr XZjqXGZhRDPmC5on4UlhesH1Z1cmoVeZeeGJ4si/ZvLfQ+Or70e550TUXxBebcIQnGCqyI KZHynBGNJ8c9VOBpXNpr1FY54WZH/XA= Received: from mail-il1-f197.google.com (mail-il1-f197.google.com [209.85.166.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-573--StfLqKFNlCtVV3SuErjwg-1; Mon, 29 Sep 2025 17:17:53 -0400 X-MC-Unique: -StfLqKFNlCtVV3SuErjwg-1 X-Mimecast-MFC-AGG-ID: -StfLqKFNlCtVV3SuErjwg_1759180673 Received: by mail-il1-f197.google.com with SMTP id e9e14a558f8ab-4272d0bebf0so9061265ab.0 for ; Mon, 29 Sep 2025 14:17:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759180673; x=1759785473; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=tBEzt7vDi7cQon8pe4PxgzLkANUC3bHfRN0ntBJldU8=; b=tZRyR9uwlNWcgyNdVR/uHxtvAaOy5ut040dHlohxD9IcI+kWTZOFjqW3wxgW7W/CzW v9Nx+1cnvobR3yIfACNkQTchn3yhglrG5hqOHYXPGbY5kywLMPuzaG/JFaOxC81yR4p3 CNpqzhWe1GdlS9sNQUk1b4DFXVWXlhyScinSTNpRqh8aQUSrbUvAump6OH42y5AN+BO8 ZYoP6OeHvNnuuJG0j/Nu7I8Y+ljaAk41XZTnNhsg0+MTE/VxIZLagWbVqDGWkChV3GjK eVhF7PT4VlDOmkV45Rnz8bJZF2f7z44/23wrXRKx4DFu38yeI72kY6nQnmfeqa2o63Gm 2lsg== X-Forwarded-Encrypted: i=1; AJvYcCVNfmIbJYnRy5LJh0FkJi9vFZkhL8UzWV9Z1TZQjnzKjPTwS0olS8V15GV6cYMvyQqbKdJXyhsklEuWzQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yx/xtH2gdwks7k4bfkWj7WU4hOKsmCDBlf37azVmsIJWRWi+/cf 4txU8htoYz89r/LhcTNy52aytX6/daxJFuQGecnEBULhyJEFKG1etBKMz1tL4ySZ6PfXqrNTAVy h8jXj+vhzMp0mWrnMzsmzFA6q13BQJomRKBjNGCzQU8rEpuXvsFrV0NBtEwk6MeYX X-Gm-Gg: ASbGncsJUZQOd/Cv3Nd7pThGZiPIY3WcnqxZFmZZLMk14/9w6U82cr7QwPUKjCQ6aTD XMEVoYTp8GAlOC7YMOCODqtjHNV+XzrQp2+PP+rX3EPQWJ6H3ORZ+YKcSYEBwrHdauKKJrQDy7b /YSHo9irMp7+aqsdx7XVEuQuOHen8ya7F80g/uc4m+JxvFW8SKyXlm6Tn9JSYlxPUipYvKJeC9s V5+qL6PDVtgYS6SFFQVn6P7ENleRpwZ3/s/pp6jqo/vexqaC14alhku3WNbuLWu9zIrkWKZN0ll ZR+ctERTsneu2zJw61/NsunPixoS42ONAA+ZtJRM9Uk= X-Received: by 2002:a05:6e02:1523:b0:425:9068:4ff with SMTP id e9e14a558f8ab-425955c8eb5mr97782355ab.1.1759180672723; Mon, 29 Sep 2025 14:17:52 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFTF4nahZRRX2gicTqxhxWdWKeUzRDCgsQQuCRfxHGJ4HNrczL75firr5hrFe4LKeaKRuPCNA== X-Received: by 2002:a05:6e02:1523:b0:425:9068:4ff with SMTP id e9e14a558f8ab-425955c8eb5mr97782155ab.1.1759180672251; Mon, 29 Sep 2025 14:17:52 -0700 (PDT) Received: from redhat.com ([38.15.36.11]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-425c05476fasm62141985ab.43.2025.09.29.14.17.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Sep 2025 14:17:51 -0700 (PDT) Date: Mon, 29 Sep 2025 15:17:49 -0600 From: Alex Williamson To: Leon Romanovsky Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , Christian =?UTF-8?B?S8O2bmln?= , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: Re: [PATCH v4 10/10] vfio/pci: Add dma-buf export support for MMIO regions Message-ID: <20250929151749.2007b192.alex.williamson@redhat.com> In-Reply-To: <53f3ea1947919a5e657b4f83e74ca53aa45814d4.1759070796.git.leon@kernel.org> References: <53f3ea1947919a5e657b4f83e74ca53aa45814d4.1759070796.git.leon@kernel.org> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 28 Sep 2025 17:50:20 +0300 Leon Romanovsky wrote: > +static int validate_dmabuf_input(struct vfio_pci_core_device *vdev, > + struct vfio_device_feature_dma_buf *dma_buf, > + struct vfio_region_dma_range *dma_ranges, > + struct p2pdma_provider **provider) > +{ > + struct pci_dev *pdev = vdev->pdev; > + u32 bar = dma_buf->region_index; > + resource_size_t bar_size; > + u64 sum; > + int i; > + > + if (dma_buf->flags) > + return -EINVAL; > + /* > + * For PCI the region_index is the BAR number like everything else. > + */ > + if (bar >= VFIO_PCI_ROM_REGION_INDEX) > + return -ENODEV; > + > + *provider = pcim_p2pdma_provider(pdev, bar); > + if (!provider) This needs to be IS_ERR_OR_NULL() or the function needs to settle on a consistent error return value regardless of CONFIG_PCI_P2PDMA. > + return -EINVAL; > + > + bar_size = pci_resource_len(pdev, bar); We get to this feature via vfio_pci_core_ioctl_feature(), which is used by several variant drivers, some of which mangle the BAR size exposed to the user, ex. hisi_acc. I'm afraid this might actually be giving dmabuf access to a portion of the BAR that isn't exposed otherwise. > + for (i = 0; i < dma_buf->nr_ranges; i++) { > + u64 offset = dma_ranges[i].offset; > + u64 len = dma_ranges[i].length; > + > + if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len)) > + return -EINVAL; > + > + if (check_add_overflow(offset, len, &sum) || sum > bar_size) > + return -EINVAL; > + } > + > + return 0; > +} > + > +int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags, > + struct vfio_device_feature_dma_buf __user *arg, > + size_t argsz) > +{ > + struct vfio_device_feature_dma_buf get_dma_buf = {}; > + struct vfio_region_dma_range *dma_ranges; > + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); > + struct p2pdma_provider *provider; > + struct vfio_pci_dma_buf *priv; > + int ret; > + > + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET, > + sizeof(get_dma_buf)); > + if (ret != 1) > + return ret; > + > + if (copy_from_user(&get_dma_buf, arg, sizeof(get_dma_buf))) > + return -EFAULT; > + > + if (!get_dma_buf.nr_ranges) > + return -EINVAL; > + > + dma_ranges = memdup_array_user(&arg->dma_ranges, get_dma_buf.nr_ranges, > + sizeof(*dma_ranges)); > + if (IS_ERR(dma_ranges)) > + return PTR_ERR(dma_ranges); > + > + ret = validate_dmabuf_input(vdev, &get_dma_buf, dma_ranges, &provider); > + if (ret) > + return ret; goto err_free_ranges; Thanks, Alex