From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 5C4282DA768 for ; Mon, 13 Oct 2025 05:32:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760333567; cv=none; b=jOAvrvC8tTyJBEhAYuvviUEfG8s3dgRyqtBZJVugNpzJL8XHpyFZTk1ewuwGvVnYWbHkOIQVFIyOTCdg054aBTLsufKYWfIyvmsfroFuWLKVh5LvsoShU/PAVw4EiBX9gMFT99a8R4uqmjNZXDZrP/fYl9e0ujZmipHurwpKXbk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760333567; c=relaxed/simple; bh=JTNhu/382e4Fm08mYKQv1wixPN/gikMoRMPBc7fyVZg=; h=From:Subject:Date:Message-ID:MIME-Version:Content-Type:To:CC; b=E+bMrdYru+QtFUwrXHImbtmGalPaAgEmTb6vaRyWHeAINy/ArpuYL9NzmlBT+qzbWP0eh3v93fDtcIFvn4EGTWZstkVQhHyE00eUPtdJMMZxQnsDMPFi6ghAUaWpt3PEzJW7vkdcS+ZbWUK8qkaDQVVktlVVKCdm0/zqigdd8tY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=fb.com header.i=@fb.com header.b=pmL3teoT; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fb.com header.i=@fb.com header.b="pmL3teoT" Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 59D3DWhn536898 for ; Sun, 12 Oct 2025 22:32:45 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=cc :content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=s2048-2025-q2; bh=xL6Ske1sMSqh8onRsi PctKwfCuLmMf34qkpKo1FjMFg=; b=pmL3teoTQIcRkE410EWfsa4N9b0DrZGyRR LEsRD/9gFg1kfXnjGHB+Z3n2xh4FGVqAGrirh4khCCVy9VQRWYJoSs2/6QQBe2oL 7mX22JmROHh37YCdIi6iE6B6BHKcKNJ7FYtbXojVLKfJRfJ9flnG2q8yj5a9ti8v ewGRyhQZH4AgYqi7qQH3pbB1rh0D353Swl/b/55yp5Liz9FBTm/7KG5fuE8mcVfI +V91LzjbidOsOsUPm7a65vNANDKql98joLEo7ddWiYQFmtB17qRYl/zPC6e6Bd5c AEe7MLZ7N/jvfqKgHLAzp3Y7YI6WWwxfy/e1UwGJUkEWeje/L5bw== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 49rsb6gdyw-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sun, 12 Oct 2025 22:32:45 -0700 (PDT) Received: from twshared30833.05.prn5.facebook.com (2620:10d:c0a8:1b::30) by mail.thefacebook.com (2620:10d:c0a9:6f::8fd4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.20; Mon, 13 Oct 2025 05:32:43 +0000 Received: by devgpu015.cco6.facebook.com (Postfix, from userid 199522) id 9CECB102FE45; Sun, 12 Oct 2025 22:32:30 -0700 (PDT) From: Alex Mastro Subject: [PATCH v4 0/3] vfio: handle DMA map/unmap up to the addressable limit Date: Sun, 12 Oct 2025 22:32:23 -0700 Message-ID: <20251012-fix-unmap-v4-0-9eefc90ed14c@fb.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAOeO7GgC/23MvQ7CIBSG4VtpmMXwVyhO3odxoHCwDLYNKNE0v XdpB4OJ4wfneReUIAZI6NQsKEIOKUxjGeLQIDuY8QY4uLIRI6ylhLTYhxd+jnczY8s9h04503u Dyv0coXzurcu17CGkxxTfezrT7fVfJVNMsZSdUpyBEwLOvj/a6Y62RGY1UzVjmGDV6t5Cr5Vmv 4xXjJKa8cI4kVYx4aTW3Zet6/oB4dbi5Q0BAAA= To: Alex Williamson CC: Jason Gunthorpe , Alejandro Jimenez , , , Alex Mastro X-Mailer: b4 0.13.0 X-FB-Internal: Safe X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDEzMDAyNiBTYWx0ZWRfX3z272fsNA5mj a5hUOmVdw3zf/hYdBAFcU4QZW782dUjQ3OkrpHPY7sEjgdWCVoHflN/Er+Uqp5F3zDbQrDFw0Bd bXZHqGDEgsKqPldmQQ/hDNUXZIYTxcM8/6aKNY4xqtY3BZFm2FjpXly4TEDewLc7gzn5TaJPBTh bhBNSgvLNeC2pSAMxT8P+hEcCjH9zznj+F/FTPW7BQ3YqyncjU/NjJ0YhxueLI5N1/G3BEBzHbC dOmMXuV9srcqcB/k+k/xPKcI1Fypw29+6GfE2Q9+5bEmT2icOqATh9qKYssJZ1KcPynGKTEu2tu 9RrmFhd0mj7VIq297acaYhsKrjsdvlLN5VATL8XSfFvOKFmlUuykbjmG4XFHmyYAe8Mb7VvF67B cm5uItrBjHRI33EmyFGM0De4lrfgKQ== X-Proofpoint-ORIG-GUID: fvtHFCarfVDL0Ycaesb8dMTsERVqQSXM X-Authority-Analysis: v=2.4 cv=BarVE7t2 c=1 sm=1 tr=0 ts=68ec8efd cx=c_pps a=MfjaFnPeirRr97d5FC5oHw==:117 a=MfjaFnPeirRr97d5FC5oHw==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VwQbUJbxAAAA:8 a=yPCof4ZbAAAA:8 a=FOH2dFAWAAAA:8 a=LN3npHLcb8nXURrLiNkA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: fvtHFCarfVDL0Ycaesb8dMTsERVqQSXM X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-13_02,2025-10-06_01,2025-03-28_01 This patch series aims to fix vfio_iommu_type.c to support VFIO_IOMMU_MAP_DMA and VFIO_IOMMU_UNMAP_DMA operations targeting IOVA ranges which lie against the addressable limit. i.e. ranges where iova_start + iova_size would overflow to exactly zero. Today, the VFIO UAPI has an inconsistency: The VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE capability of VFIO_IOMMU_GET_INFO reports that ranges up to the end of the address space are available for use, but are not really due to bugs in handling boundary conditions. For example: vfio_find_dma_first_node is called to find the first dma node to unmap given an unmap range of [iova..iova+size). The check at the end of the function intends to test if the dma result lies beyond the end of the unmap range. The condition is incorrectly satisfied when iova+size overflows to zero, causing the function to return NULL. The same issue happens inside vfio_dma_do_unmap's while loop. This bug was also reported by Alejandro Jimenez in [1][2]. Of primary concern are locations in the current code which perform comparisons against (iova + size) expressions, where overflow to zero is possible. The initial list of candidate locations to audit was taken from the following: $ rg 'iova.*\+.*size' -n drivers/vfio/vfio_iommu_type1.c | rg -v '\- 1' 173: else if (start >= dma->iova + dma->size) 192: if (start < dma->iova + dma->size) { 216: if (new->iova + new->size <= dma->iova) 1060: dma_addr_t iova = dma->iova, end = dma->iova + dma->size; 1233: if (dma && dma->iova + dma->size != iova + size) 1380: if (dma && dma->iova + dma->size != iova + size) 1501: ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, 1504: vfio_unpin_pages_remote(dma, iova + dma->size, pfn, 1721: while (iova < dma->iova + dma->size) { 1743: i = iova + size; 1744: while (i < dma->iova + dma->size && 1754: size_t n = dma->iova + dma->size - iova; 1785: iova += size; 1810: while (iova < dma->iova + dma->size) { 1823: i = iova + size; 1824: while (i < dma->iova + dma->size && 2919: if (range.iova + range.size < range.iova) This series spend the first couple commits making mechanical preparations before the fix lands in the last commit. [1] https://lore.kernel.org/qemu-devel/20250919213515.917111-1-alejandro.j.jimenez@oracle.com/ [2] https://lore.kernel.org/all/68e18f2c-79ad-45ec-99b9-99ff68ba5438@oracle.com/ Signed-off-by: Alex Mastro --- Changes in v4: - Fix type assigned to iova_end - Clarify overflow checking, add checks to vfio_iommu_type1_dirty_pages - Consider npage==0 an error for vfio_iommu_type1_pin_pages - Link to v3: https://lore.kernel.org/r/20251010-fix-unmap-v3-0-306c724d6998@fb.com Changes in v3: - Fix handling of unmap_all in vfio_dma_do_unmap - Fix !range.size to return -EINVAL for VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP - Dedup !range.size checking - Return -EOVERFLOW on check_*_overflow - Link to v2: https://lore.kernel.org/r/20251007-fix-unmap-v2-0-759bceb9792e@fb.com Changes in v2: - Change to patch series rather than single commit - Expand scope to fix more than just the unmap discovery path - Link to v1: https://lore.kernel.org/r/20251005-fix-unmap-v1-1-6687732ed44e@fb.com --- Alex Mastro (3): vfio/type1: sanitize for overflow using check_*_overflow vfio/type1: move iova increment to unmap_unpin_* caller vfio/type1: handle DMA map/unmap up to the addressable limit drivers/vfio/vfio_iommu_type1.c | 173 +++++++++++++++++++++++++--------------- 1 file changed, 110 insertions(+), 63 deletions(-) --- base-commit: 407aa63018d15c35a34938633868e61174d2ef6e change-id: 20251005-fix-unmap-c3f3e87dabfa Best regards, -- Alex Mastro