From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) (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 020323FD129; Thu, 30 Apr 2026 10:04:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.153.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777543448; cv=none; b=bohKtb9Sss8sLla9LfRe8Xg3JF2IzRQVSYwI8NK0gj7XkwlXedDjik5NCRWNBqcxa/PFaxoBK8D9Yp+hCpYG7Fg1KwjCb2CnavEnBuCpcvleJxmOpfBbGcbXOVu7OS2tdxUZTgeMolfmlYei52C90WxbbooeYwbAStXiQulZETM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777543448; c=relaxed/simple; bh=oP1sNw3lOw6zB5Y/XHldmRoMKbeGbgHUXpQzx4+4Mq4=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=J2LVIKtuAoEOrADuQYWuyJ25PK+ikHehuWnVGfhiQJh0Tl1MlL60WFDydX5OFtfyJ/BBBc0CLpAjTQi1GzF6oii7on8OifwL57yQLqTUxiABSlRkfMZVxPyVf2X7zn5DXv0RUVhjP1bzrez0w+nQAmMJYxcCZ+xxkcyHuhfgdjA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=kH3hSo2u; arc=none smtp.client-ip=67.231.153.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.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=meta.com header.i=@meta.com header.b="kH3hSo2u" Received: from pps.filterd (m0528006.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 63U6NV2Z3593963; Thu, 30 Apr 2026 03:03:49 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=s2048-2025-q2; bh=GjFDQPDXNHcpO5qiMh fQwTAt8BEUXKtlfSQH1GN4nOc=; b=kH3hSo2un8OHXX2nUVQZOxKZtnf7GjZs0w 4sspuH+9gpgZfi6CL/J1b9bd7MxdCFwGXtRiZaMvC8bqGNZwAFF3qNckFd7rpWUg CrHrtjdbeuEvwwW2waMA2OCbhJhziU5dgsXqQG0RCb0Y4FT1vcbKG5CoAYCtfO7m CSWLS/kNlfm50v8GOEZ/7NnKm07+DA1wuSQU8L1fA68y0/HDmLioWs3Ify2iZDIb RAgmBn2ErBXpOPJWd3Hejd78cK/4fh64ROpM7jFnkE0NOogzP0WPjeGLHTcAQQ8u RijYRXf3UpZkRe5LdVXVPRXwcd1ITL28AU10d6eQ1z1UabMofz1g== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4dse8nd67e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Thu, 30 Apr 2026 03:03:49 -0700 (PDT) Received: from localhost (2620:10d:c0a8:1b::8e35) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.37; Thu, 30 Apr 2026 10:03:48 +0000 From: Matt Evans To: Alex Williamson , Kevin Tian , Jason Gunthorpe , Ankit Agrawal , Alistair Popple , Leon Romanovsky , Kees Cook , Shameer Kolothum , Yishai Hadas CC: Alexey Kardashevskiy , Eric Auger , Peter Xu , Vivek Kasireddy , Zhi Wang , , , Subject: [PATCH v3 0/3] vfio/pci: Request resources and map BARs at enable time Date: Thu, 30 Apr 2026 03:03:19 -0700 Message-ID: <20260430100340.2787446-1-mattev@meta.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: Ou6f_EeCtD1iu2B9KAFMNHRqQoh9NRWO X-Authority-Analysis: v=2.4 cv=XLQAjwhE c=1 sm=1 tr=0 ts=69f32905 cx=c_pps a=MfjaFnPeirRr97d5FC5oHw==:117 a=MfjaFnPeirRr97d5FC5oHw==:17 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=7x6HtfJdh03M6CCDgxCd:22 a=kkcUborcUVj0H7zxAXTl:22 a=VwQbUJbxAAAA:8 a=VabnemYjAAAA:8 a=18-LhrYFQHd_5z6HW7oA:9 a=gKebqoRLp9LExxC7YDUY:22 X-Proofpoint-ORIG-GUID: Ou6f_EeCtD1iu2B9KAFMNHRqQoh9NRWO X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDMwMDEwMCBTYWx0ZWRfXz1bTEZeDZ7UD cT5EUaGv6PQDJBywzI7qOIfiXCTFS8zlBccn8VG93IqRTqn1S2Uygh8tIpAwqt6tr5qZNYMjpHR uZka/lGhis8/3IVvFhD65i7DqghznnQTJzAOR91XEvbqq1AX44SYcpMZu2AblIXVG2DgcBzinwh rAPvJGXAZB3xxf3R86OKobWP3XUzjZ9l06rm/UE9wVsiiEg6q6zMEH0lYvR8qruvcfAg0v9mQlT iv0gVPBwOZJOmlaBHBERp/8GYWqsERMhQX79SKb6Y257vlq+TKDbo4s1o6XgW20KkXKm2m+gQ9k ueuf8KNq+Lzxb5o1B+s+Ea5QHdsbqsxISpjk0U/OB+DjUEARw4zaok1Ml94gJg8Mou77jBQPkXN GB+k/M2oZhDK4nQIhGGBvpaC7b/zY5Me5KrRWsLPxEcecSz6Tod2sbrfu6dWCOt+jxwL9WT+HW6 mgamtLYa0sm9dSU9BjQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-30_03,2026-04-28_01,2025-10-01_01 Hi, These patches fix a potential race for concurrent calls to vfio_pci_core_setup_barmap(), and a DMABUF missing check for resource before the export. Discussion on a previous series (different, replaced by this one) is here: https://lore.kernel.org/kvm/20260415181423.1008458-1-mattev@meta.com Responses in that thread indicated there wasn't a strong historical reason to require the mapping to be performed on-demand at BAR reference time. It's much simpler to move this earlier, to vfio_pci_core_enable(), and that then avoids having to deal with concurrent requests later. The first patch requests PCI resources and pci_iomap() of the BARs from vfio_pci_core_enable(), moving this out of vfio_pci_core_setup_barmap(). Some callers rely on vfio_pci_core_setup_barmap() for its ioremap() effect, and other callers use it for its resource-acquiring effect. The function turns into a cheap error check that both these actions have occurred and keeps the same error behaviour. The second patch refactors that function plus the various vdev->barmap[] accesses into vfio_pci_core_get_iomap() which returns either a pointer to the mapping or an ERR_PTR() describing why it doesn't exist. This is used by callers that need the mapping, but also by other callers to check that the resource/mapping step was successful. NOTE: This removes the EXPORT_SYMBOL_GPL(vfio_pci_core_setup_barmap). It does not re-add an export for vfio_pci_core_get_iomap() yet. (I wanted to check the preference/policy here.) The third patch adds the resource check to VFIO DMABUF export, which was previously able to export an unrequested resource. Although patch 1 at first appears to fix this by requesting resources at enable time, code using the BAR still needs to check the resource really was acquired. === Changes === v3: - Remove the separate tracking of the BAR mapping versus the acquiring its resource. Errors from failing iomap vs resource reservation are ERR_PTR()-elcoded into barmap[bar]. - Remove the separate test helper, and add vfio_pci_core_get_iomap(). This gets the iomap base or is used check for error/failure to acquire the resource. Added comments at call sites explaining whether they want to just ensure the resource is reserved versus actually use the mapping. v2: https://lore.kernel.org/kvm/20260423182517.2286030-1-mattev@meta.com/ - Don't fail if resources can't be requested or iomapped, even for valid BARs, as this would change the userspace-observable error behaviour. Specifically, if there was an issue with one particular BAR which happened to never be used, then userspace would never encounter an error for it. Track iomap and resource-acquisition status per BAR. - Break out the checks for resource success from those for iomap success, in the form of the two new helpers. - Third patch to add the check to VFIO DMABUF export, because init-time requests can now fail. v1: https://lore.kernel.org/kvm/20260421174143.3883579-1-mattev@meta.com/ Matt Evans (3): vfio/pci: Set up bar resources and maps in vfio_pci_core_enable() vfio/pci: Replace vfio_pci_core_setup_barmap() with vfio_pci_core_get_iomap() vfio/pci: Check BAR resources before exporting a DMABUF drivers/vfio/pci/nvgrace-gpu/main.c | 17 ++++++----- drivers/vfio/pci/vfio_pci_core.c | 44 +++++++++++++++++++++++++---- drivers/vfio/pci/vfio_pci_dmabuf.c | 6 ++-- drivers/vfio/pci/vfio_pci_rdwr.c | 42 ++++++--------------------- drivers/vfio/pci/virtio/legacy_io.c | 13 ++++----- include/linux/vfio_pci_core.h | 19 ++++++++++++- 6 files changed, 84 insertions(+), 57 deletions(-) -- 2.47.3