[{"id":3680014,"web_url":"http://patchwork.ozlabs.org/comment/3680014/","msgid":"<35163ccd-a282-417c-865e-9cc111b70fa5@deltatee.com>","list_archive_url":null,"date":"2026-04-21T18:14:57","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":70191,"url":"http://patchwork.ozlabs.org/api/people/70191/","name":"Logan Gunthorpe","email":"logang@deltatee.com"},"content":"On 2026-04-21 11:43, Matt Evans wrote:\n> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> pdev->non_mappable_bars set.\n> \n> Consumers such as VFIO were previously able to map these for access by\n> the CPU or P2P. Update the comment on non_mappable_bars to show it\n> refers to any access, not just userspace CPU access.\n> \n> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> Signed-off-by: Matt Evans \n\nThis makes sense to me, thanks.\n\nReviewed-by: Logan Gunthorpe ","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=deltatee.com header.i=@deltatee.com header.a=rsa-sha256\n header.s=20200525 header.b=UDSWvqt7;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-52869-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=deltatee.com header.i=@deltatee.com\n header.b=\"UDSWvqt7\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=204.191.154.188","smtp.subspace.kernel.org;\n dmarc=pass (p=quarantine dis=none) header.from=deltatee.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=deltatee.com"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org [172.234.253.10])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0Vtb056lz1yGt\n\tfor ; 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s=20200525; h=Subject:In-Reply-To:From:References:Cc:To:\n\tMIME-Version:Date:Message-ID:content-disposition;\n\tbh=B8hFtIuFqE25OFd700xADDBrxfR+UtQr6/9m0uTtlDY=; b=UDSWvqt7qXPCMW0sHl5h2hYCS+\n\t3sxMQ51aoRE87mEiCrV7LttIHQQf7ueERg9Dv2TRv5RWjwHXaFtc9RRETL9iCbMC4d7Ax/aMjeUQw\n\tSiCriXSSQ0gB+s6RBUvk9aQsoaDXBouHW1dsN5++++yEsBisEA3WfQ2pD0ULwn8f4pOthlCzxb+Q3\n\tV2iyZo/3PCLG/28Z7Joq3BhrsR93j0rC6qKeJcj/6DssSww23I88wHyi54RbC/nlETWcogjpwczlz\n\tW8qQR2YgimemZ3g/1c4Af1Etu+kwY5JkWNTHCVGmdtlBVn3hMLy/SANWLqC0CEroWZtazlXJZtTW6\n\t+v5dqs2g==;","Message-ID":"<35163ccd-a282-417c-865e-9cc111b70fa5@deltatee.com>","Date":"Tue, 21 Apr 2026 12:14:57 -0600","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","To":"Matt Evans , Bjorn Helgaas ,\n Ankit Agrawal , Leon Romanovsky ,\n Alex Williamson , Niklas Schnelle ","Cc":"linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org","References":"<20260421174351.3897842-1-mattev@meta.com>","Content-Language":"en-CA","From":"Logan Gunthorpe ","In-Reply-To":"<20260421174351.3897842-1-mattev@meta.com>","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"7bit","X-SA-Exim-Connect-IP":"172.16.1.162","X-SA-Exim-Rcpt-To":"mattev@meta.com, bhelgaas@google.com, ankita@nvidia.com,\n leon@kernel.org, alex@shazbot.org, schnelle@linux.ibm.com,\n linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org","X-SA-Exim-Mail-From":"logang@deltatee.com","X-Spam-Level":"","Subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","X-SA-Exim-Version":"4.2.1 (built Sun, 23 Feb 2025 07:57:16 +0000)","X-SA-Exim-Scanned":"Yes (on ale.deltatee.com)"}},{"id":3680041,"web_url":"http://patchwork.ozlabs.org/comment/3680041/","msgid":"<20260421194954.GA28413@unreal>","list_archive_url":null,"date":"2026-04-21T19:49:54","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":68852,"url":"http://patchwork.ozlabs.org/api/people/68852/","name":"Leon Romanovsky","email":"leon@kernel.org"},"content":"On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:\n> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> pdev->non_mappable_bars set.\n> \n> Consumers such as VFIO were previously able to map these for access by\n> the CPU or P2P. Update the comment on non_mappable_bars to show it\n> refers to any access, not just userspace CPU access.\n> \n> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n\nI don't object to the patch, but this Fixes line doesn't look correct.\nnon_mappable_bars applies only to s390, which doesn't support p2p. That\nwasn't prevented before 372d6d1b8ae3c refactoring too.\n\nThanks","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=JS8qELIw;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-52876-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"JS8qELIw\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0Y0P4RrVz1yGs\n\tfor ; Wed, 22 Apr 2026 05:52:05 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sea.lore.kernel.org (Postfix) with ESMTP id 3FED23035A9A\n\tfor ; Tue, 21 Apr 2026 19:50:01 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 64C0F3DCDA4;\n\tTue, 21 Apr 2026 19:50:00 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 41C03178372;\n\tTue, 21 Apr 2026 19:50:00 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id 2A31EC2BCB0;\n\tTue, 21 Apr 2026 19:49:58 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776801000; cv=none;\n b=bY8Jla9+D3jI87BjXyjDfgi2nzOj8Rr8V/B6DHS+ZvRoC0JtCZLu6Mye7NsngAzUV5X4TaOJMWpyRO6Fh7gjsAWKrbdBHYzTPF3NxciZaP86Z1Y3iDAxi4B8xs1CTek/rbjwxti5c6l92KU6m1uaNH1XLMt1lxqfTnkDsQpAgf8=","ARC-Message-Signature":"i=1; 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charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20260421174351.3897842-1-mattev@meta.com>"}},{"id":3680374,"web_url":"http://patchwork.ozlabs.org/comment/3680374/","msgid":"<8de7b03f58c53bf40933f1afa5833419a58cef7c.camel@linux.ibm.com>","list_archive_url":null,"date":"2026-04-22T09:19:52","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":78856,"url":"http://patchwork.ozlabs.org/api/people/78856/","name":"Niklas Schnelle","email":"schnelle@linux.ibm.com"},"content":"On Tue, 2026-04-21 at 10:43 -0700, Matt Evans wrote:\n> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> pdev->non_mappable_bars set.\n> \n> Consumers such as VFIO were previously able to map these for access by\n> the CPU or P2P. Update the comment on non_mappable_bars to show it\n> refers to any access, not just userspace CPU access.\n> \n> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> Signed-off-by: Matt Evans \n> ---\n> \n> This arises from Alex Williamson's suggestion to test\n> non_mappable_bars when getting the provider, with discussion here:\n> \n> https://lore.kernel.org/kvm/20260415181623.1021090-1-mattev@meta.com/\n> \n> The goal was to prevent a hole where VFIO could export DMABUFs for\n> BARs marked non-mappable, and to fix for all users of the provider\n> rather than just VFIO. Alex observed that non_mappable_bars should be\n> taken to mean BARs weren't usable by the CPU _or_ peers and,\n> considering that, its comment about userspace access wasn't quite\n> right.\n> \n> \n> drivers/pci/p2pdma.c | 3 ++-\n> include/linux/pci.h | 2 +-\n> 2 files changed, 3 insertions(+), 2 deletions(-)\n> \n> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c\n> index 7c898542af8d..4a783413f466 100644\n> --- a/drivers/pci/p2pdma.c\n> +++ b/drivers/pci/p2pdma.c\n> @@ -318,7 +318,8 @@ struct p2pdma_provider *pcim_p2pdma_provider(struct pci_dev *pdev, int bar)\n> {\n> \tstruct pci_p2pdma *p2p;\n> \n> -\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))\n> +\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM) ||\n> +\t pdev->non_mappable_bars)\n> \t\treturn NULL;\n> \n> \tp2p = rcu_dereference_protected(pdev->p2pdma, 1);\n> diff --git a/include/linux/pci.h b/include/linux/pci.h\n> index 2c4454583c11..1e6802017d6b 100644\n> --- a/include/linux/pci.h\n> +++ b/include/linux/pci.h\n> @@ -508,7 +508,7 @@ struct pci_dev {\n> \tunsigned int\tno_command_memory:1;\t/* No PCI_COMMAND_MEMORY */\n> \tunsigned int\trom_bar_overlap:1;\t/* ROM BAR disable broken */\n> \tunsigned int\trom_attr_enabled:1;\t/* Display of ROM attribute enabled? */\n> -\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped to user-space */\n> +\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped by CPU or peers */\n> \tpci_dev_flags_t dev_flags;\n> \tatomic_t\tenable_cnt;\t/* pci_enable_device has been called */\n> \n\nSorry for the late reply. For s390's ISM device this definitely makes\nsense. The BAR can indeed not be accessed by P2P and extending this\nseems reasonable to me. \n\nFeel free to add my:\n\nReviewed-by: Niklas Schnelle \n\nThanks,\nNiklas","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=aOXcjhxM;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-52932-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com\n header.b=\"aOXcjhxM\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=148.163.158.5","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=linux.ibm.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=linux.ibm.com"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0v5R5LGxz1yD5\n\tfor ; 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charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","Date":"Wed, 22 Apr 2026 11:19:52 +0200","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","User-Agent":"Evolution 3.58.3 (3.58.3-1.fc43) ","X-TM-AS-GCONF":"00","X-Proofpoint-Reinject":"loops=2 maxloops=12","X-Proofpoint-ORIG-GUID":"qAd29RjgHtMCGDtl7JMvERW9lwz0z0wL","X-Authority-Analysis":"v=2.4 cv=Ksp9H2WN c=1 sm=1 tr=0 ts=69e892f8 cx=c_pps\n a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17\n a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22\n a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8\n a=VabnemYjAAAA:8 a=VnNF1IyMAAAA:8 a=_dJdq47d6hiFVcz4INMA:9 a=QEXdDO2ut3YA:10\n a=gKebqoRLp9LExxC7YDUY:22","X-Proofpoint-GUID":"-eOgB84tUtr3Qt4eAXc8AFBJcS0Eet52","X-Proofpoint-Spam-Details-Enc":"AW1haW4tMjYwNDIyMDA4OCBTYWx0ZWRfXx6qdu6HwQBGf\n MHjmrxFLn4ma0AUNZSKBbyLPVxsanhuWlpqOKZFBV3V9ju5YApLCb86Qo500r3xFSjRhNWuU4ue\n UwwMdAaRdt3hCntwSSm6M5mC3VGAQ4IAranAQCpheTuxTW1S51KN7SnNfgeBHJOL4pWFsnt6BJM\n EVV/XXGRkSY5JxOg2wrI2mqorWlrIooqfWhSe7KksHBJWPUIur4ijoDF7dq+Ko5mT6dEdUh5Fe1\n fXGqjrA7FeELoVk0QJ5e3HK5fy0CXMQ6fMLgzQXMKkIpFK3/DZVrZ3WeX39mRsYts5JYPGvTTb/\n kIO9sR/aurbtb8i30DnBT1YgbJ0SgfgD1CHQ4tYLTRgwIsyTlMkgBWSrtFGubw6HBQT3UzrVRkV\n 8IMo2pZ15w1vNw8RbOhLKUDZv54Ba9dOwKI/R0VpumLQRdBVTZe9O6QhMaJxOZJauvQL4wmcvrO\n +Ajf62xo//Y/oaKt+Xw==","X-Proofpoint-Virus-Version":"vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-04-22_01,2026-04-21_02,2025-10-01_01","X-Proofpoint-Spam-Details":"rule=outbound_notspam policy=outbound score=0\n bulkscore=0 impostorscore=0 malwarescore=0 phishscore=0 priorityscore=1501\n lowpriorityscore=0 clxscore=1011 adultscore=0 suspectscore=0 spamscore=0\n classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0\n reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2604220088"}},{"id":3680650,"web_url":"http://patchwork.ozlabs.org/comment/3680650/","msgid":"","list_archive_url":null,"date":"2026-04-22T14:22:53","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":93208,"url":"http://patchwork.ozlabs.org/api/people/93208/","name":"Matt Evans","email":"mattev@meta.com"},"content":"Hi Leon,\n\nOn 21/04/2026 20:49, Leon Romanovsky wrote:\n> \n> On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:\n>> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n>> pdev->non_mappable_bars set.\n>>\n>> Consumers such as VFIO were previously able to map these for access by\n>> the CPU or P2P. Update the comment on non_mappable_bars to show it\n>> refers to any access, not just userspace CPU access.\n>>\n>> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> \n> I don't object to the patch, but this Fixes line doesn't look correct.\n> non_mappable_bars applies only to s390, which doesn't support p2p. That\n> wasn't prevented before 372d6d1b8ae3c refactoring too.\n\nThanks; I'd chosen that commit as it adds the function that the \nadditional test is being added to.\n\nAs an example consumer, vfio_pci_core_get_dmabuf_phys() added in \n5d74781ebc86 (\"vfio/pci: Add dma-buf export support for MMIO regions\") \ncould do an export when it shouldn't. (And with my other mmap series, a \nCPU could then access it, not even P2P.) I suppose this patch could \npoint to 5d74781ebc86 instead (which allows the naughty DMABUF export), \nbut I couldn't prove VFIO DMABUF export was the only thing using \npcim_p2pdma_provider() added in 372d6d1b8ae3c (especially as that \nsymbol's exported).\n\nIt still seems most watertight to treat this as a fix for anything \ncontaining 372d6d1b8ae3c, but if you feel it's not right what would be a \nbetter one?\n\nAlso, in the other thread (linked above) Alex made the point that whilst \n_today_ non_mappable_bars is only set by one s390 device, he expects \nfuture quirks or reasons to exclude mappings would also use \nnon_mappable_bars so we shouldn't consider it a s390-specific thing.\n\n\nCheers,\n\n\nMatt","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=meta.com header.i=@meta.com header.a=rsa-sha256\n header.s=s2048-2025-q2 header.b=NlYNgjcL;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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charset=UTF-8; format=flowed","Content-Transfer-Encoding":"7bit","X-Authority-Analysis":"v=2.4 cv=NInlPU6g c=1 sm=1 tr=0 ts=69e8d9c2 cx=c_pps\n a=wEP8DlPgTf/vqF+yE6f9lg==:117 a=2UbFsIa4v//lIgRL4kGwwA==:17\n a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22\n a=7x6HtfJdh03M6CCDgxCd:22 a=U_y8lYiYyhHBU5rMqhb2:22 a=A9ac8u1S9ebtMFDS4YIA:9\n a=QEXdDO2ut3YA:10 a=bBxd6f-gb0O0v-kibOvt:22","X-Proofpoint-GUID":"vk61F0ax3pCnbmfZa7oZTq8dywNpF-N-","X-Proofpoint-ORIG-GUID":"vk61F0ax3pCnbmfZa7oZTq8dywNpF-N-","X-Proofpoint-Spam-Details-Enc":"AW1haW4tMjYwNDIyMDEzOSBTYWx0ZWRfX5Cxi+gjyqnIa\n FN6xC0OVnlvzLyhcFXcTYgGVvw7zI1tIv7CyU/FOpEUQWHTQDGF1MXaWTV3lgRpRdMXttAteROo\n 52pMfZkUYGFJAIxMjZtADEQpQ7cpClNbl/07op74Z2wyhCViLOeOVp1eEH7GV15ut7KPDcuRhnK\n FL1iCRB93zguU097gigYlVWAHPv6WM3zB6MovSgUA5kVLrjHvBeg2NuIndmGvv/WbiDYgwYmLsv\n Dd4vg7T1lo7gvtOzbQRO4KZMfk3IJ58vdjBpxvG4A/bY/FCuAUc+UXSAKkzTZoUSuOsJu8WAEkC\n N7NcYnNsCmTxIAk2W67FqBuO45/3OTwbGbq6WLUUzo2GgSuJ/EaWgjiUKEHQwi2WoTlCEKZGHrI\n eC/Hu4AsPifexVL313+7PrGhxGnYJHLtqqf0A3Tw8hyLwfi0OW6yYLTtPbFbzJMJmuBJUyok1h6\n VnaloN5kfGc7OoUBCWg==","X-Proofpoint-Virus-Version":"vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-04-22_01,2026-04-21_02,2025-10-01_01"}},{"id":3680663,"web_url":"http://patchwork.ozlabs.org/comment/3680663/","msgid":"<20260422090146.6faf00f8@shazbot.org>","list_archive_url":null,"date":"2026-04-22T15:01:46","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":91887,"url":"http://patchwork.ozlabs.org/api/people/91887/","name":"Alex Williamson","email":"alex@shazbot.org"},"content":"On Tue, 21 Apr 2026 10:43:51 -0700\nMatt Evans wrote:\n\n> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> pdev->non_mappable_bars set.\n> \n> Consumers such as VFIO were previously able to map these for access by\n> the CPU or P2P. Update the comment on non_mappable_bars to show it\n> refers to any access, not just userspace CPU access.\n> \n> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> Signed-off-by: Matt Evans \n> ---\n> \n> This arises from Alex Williamson's suggestion to test\n> non_mappable_bars when getting the provider, with discussion here:\n> \n> https://lore.kernel.org/kvm/20260415181623.1021090-1-mattev@meta.com/\n> \n> The goal was to prevent a hole where VFIO could export DMABUFs for\n> BARs marked non-mappable, and to fix for all users of the provider\n> rather than just VFIO. Alex observed that non_mappable_bars should be\n> taken to mean BARs weren't usable by the CPU _or_ peers and,\n> considering that, its comment about userspace access wasn't quite\n> right.\n> \n> \n> drivers/pci/p2pdma.c | 3 ++-\n> include/linux/pci.h | 2 +-\n> 2 files changed, 3 insertions(+), 2 deletions(-)\n> \n> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c\n> index 7c898542af8d..4a783413f466 100644\n> --- a/drivers/pci/p2pdma.c\n> +++ b/drivers/pci/p2pdma.c\n> @@ -318,7 +318,8 @@ struct p2pdma_provider *pcim_p2pdma_provider(struct pci_dev *pdev, int bar)\n> {\n> \tstruct pci_p2pdma *p2p;\n> \n> -\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))\n> +\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM) ||\n> +\t pdev->non_mappable_bars)\n> \t\treturn NULL;\n> \n> \tp2p = rcu_dereference_protected(pdev->p2pdma, 1);\n> diff --git a/include/linux/pci.h b/include/linux/pci.h\n> index 2c4454583c11..1e6802017d6b 100644\n> --- a/include/linux/pci.h\n> +++ b/include/linux/pci.h\n> @@ -508,7 +508,7 @@ struct pci_dev {\n> \tunsigned int\tno_command_memory:1;\t/* No PCI_COMMAND_MEMORY */\n> \tunsigned int\trom_bar_overlap:1;\t/* ROM BAR disable broken */\n> \tunsigned int\trom_attr_enabled:1;\t/* Display of ROM attribute enabled? */\n> -\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped to user-space */\n> +\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped by CPU or peers */\n> \tpci_dev_flags_t dev_flags;\n> \tatomic_t\tenable_cnt;\t/* pci_enable_device has been called */\n> \n\nShould pcim_p2pdma_init() separately test pdev->non_mappable_bars\nbefore the rcu-deref/kzalloc of the pci_p2pdma object and return\n-EOPNOTSUPP?\n\nThat then invokes the same error paths we'd see if we simply don't have\np2pdma in the kernel and handles the pci_p2pdma_add_resource() path\nautomatically as well.\n\nThis pcim_p2pdma_provider() test is really then just suppressing the\nWARN_ON that we'd otherwise see by not finding the p2p object on the\ndevice. Thanks,\n\nAlex","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=shazbot.org header.i=@shazbot.org header.a=rsa-sha256\n header.s=fm1 header.b=Wa+WHRfs;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=messagingengine.com header.i=@messagingengine.com\n header.a=rsa-sha256 header.s=fm2 header.b=eCbT5UeV;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=linux-pci+bounces-52983-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=shazbot.org header.i=@shazbot.org\n header.b=\"Wa+WHRfs\";\n\tdkim=pass (2048-bit key) header.d=messagingengine.com\n header.i=@messagingengine.com header.b=\"eCbT5UeV\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=103.168.172.152","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=shazbot.org","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=shazbot.org"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g12WX0jngz1y2d\n\tfor ; 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x86_64-pc-linux-gnu)","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain; charset=US-ASCII","Content-Transfer-Encoding":"7bit"}},{"id":3680670,"web_url":"http://patchwork.ozlabs.org/comment/3680670/","msgid":"<20260422151906.GB28413@unreal>","list_archive_url":null,"date":"2026-04-22T15:19:06","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":68852,"url":"http://patchwork.ozlabs.org/api/people/68852/","name":"Leon Romanovsky","email":"leon@kernel.org"},"content":"On Wed, Apr 22, 2026 at 03:22:53PM +0100, Matt Evans wrote:\n> Hi Leon,\n> \n> On 21/04/2026 20:49, Leon Romanovsky wrote:\n> > \n> > On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:\n> > > Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> > > pdev->non_mappable_bars set.\n> > > \n> > > Consumers such as VFIO were previously able to map these for access by\n> > > the CPU or P2P. Update the comment on non_mappable_bars to show it\n> > > refers to any access, not just userspace CPU access.\n> > > \n> > > Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> > \n> > I don't object to the patch, but this Fixes line doesn't look correct.\n> > non_mappable_bars applies only to s390, which doesn't support p2p. That\n> > wasn't prevented before 372d6d1b8ae3c refactoring too.\n> \n> Thanks; I'd chosen that commit as it adds the function that the additional\n> test is being added to.\n\nCan I suggest slightly different solution?\nIf CONFIG_..._S390 is set, we will unset CONFIG_PCI_P2PDMA and pcim_p2pdma_provider()\nwill be compiled to return NULL, without changing non_mappable_bars\ndescription.\n\nThanks","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=jk2yVjzd;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-52984-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"jk2yVjzd\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g130v3ydYz1yD5\n\tfor ; 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charset=us-ascii","Content-Disposition":"inline","In-Reply-To":""}},{"id":3681515,"web_url":"http://patchwork.ozlabs.org/comment/3681515/","msgid":"<9803c500aead703be8ebbae9d8514d1359784e20.camel@linux.ibm.com>","list_archive_url":null,"date":"2026-04-23T14:55:29","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":78856,"url":"http://patchwork.ozlabs.org/api/people/78856/","name":"Niklas Schnelle","email":"schnelle@linux.ibm.com"},"content":"On Wed, 2026-04-22 at 18:19 +0300, Leon Romanovsky wrote:\n> On Wed, Apr 22, 2026 at 03:22:53PM +0100, Matt Evans wrote:\n> > Hi Leon,\n> > \n> > On 21/04/2026 20:49, Leon Romanovsky wrote:\n> > > \n> > > On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:\n> > > > Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n> > > > pdev->non_mappable_bars set.\n> > > > \n> > > > Consumers such as VFIO were previously able to map these for access by\n> > > > the CPU or P2P. Update the comment on non_mappable_bars to show it\n> > > > refers to any access, not just userspace CPU access.\n> > > > \n> > > > Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n> > > \n> > > I don't object to the patch, but this Fixes line doesn't look correct.\n> > > non_mappable_bars applies only to s390, which doesn't support p2p. That\n> > > wasn't prevented before 372d6d1b8ae3c refactoring too.\n> > \n> > Thanks; I'd chosen that commit as it adds the function that the additional\n> > test is being added to.\n> \n> Can I suggest slightly different solution?\n> If CONFIG_..._S390 is set, we will unset CONFIG_PCI_P2PDMA and pcim_p2pdma_provider()\n> will be compiled to return NULL, without changing non_mappable_bars\n> description.\n> \n> Thanks\n\nHi Leon,\n\nI'm not sure this is an ideal solution for the longer term. While ISM\ndefinitely can't do P2P and is more akin to an emulated PCI device in\nits actual implementation, other PCI devices on the platform such as\nConnectX family NICs, NVMes and the IBM Spyre Accelerator are much more\nrun off the mill. \n\nSo, I'd prefer not to create restrictions unnecessarily. Now there are\nother unusual properties like the fact that all OSs on s390 run\nvirtualized with PCI functions passed-through by a machine level\nhypervisor. That and firmware also control root ports and PCIe\nswitches. Still, I don't believe there is anything fundamentally\npreventing P2P to work in the future. While we could then take this\nrestriction out again, I'd prefer not to introduce it in the first\nplace unless we have to.\n\nThanks,\nNiklas Schnelle","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=e4t3imk/;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=linux-pci+bounces-53047-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com\n header.b=\"e4t3imk/\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=148.163.156.1","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=linux.ibm.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=linux.ibm.com"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g1fN64mSTz1yD5\n\tfor ; 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charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","Date":"Thu, 23 Apr 2026 16:55:29 +0200","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","User-Agent":"Evolution 3.58.3 (3.58.3-1.fc43) ","X-TM-AS-GCONF":"00","X-Proofpoint-Reinject":"loops=2 maxloops=12","X-Proofpoint-GUID":"0cmBSsbFJcSNz14z4SlFVe-xcpTlEpuH","X-Proofpoint-Spam-Details-Enc":"AW1haW4tMjYwNDIzMDE0OCBTYWx0ZWRfX/Vt1JU5GYUs4\n j2gM4cZwvoLJDdh8jGjpN1+6l27twLpWwWqVCcYVf+LFo3kNSotfL+BMy6qmSnSeRE34+aeEkSn\n hrw71TvQL5c71y75Xd+qdHqAx3uKDRvcCZq3tIjpmWc9nv+BNZSIdMvFAZZM7WSJjjELPlo23/Z\n aXMzTEh3SUyWSTLWAz6jClqX+Ptc5mp2xt4aJiAcfiDg+poZ02ipfs91Qo6LBvwRFXuF7R6XNhs\n CjIr2XgO1cdIw2ZbWb2SV7/eSpmhNlpeJUU78cQzLK2WcpAm7eFnin7XY9Lxh/k/JmwaojStX2u\n iKMMbWNlsUyh/WUkKzQ8oKa9gMkJsOpV6Ykhtwpm137ODm/8aqbm4eFxjlG5zw+HB8t2tAxY7IV\n kJZ6GHAqXh9KhmDuBwgSt969eMdHgUXNpiYCA1iv5qE2eBRMATSqqxgrpXLIC3/D1VQ39ieonEo\n dpveVva1A/ZVPrNZ5Fg==","X-Authority-Analysis":"v=2.4 cv=C8LZDwP+ c=1 sm=1 tr=0 ts=69ea3322 cx=c_pps\n a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17\n a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22\n a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=LQvJE2i9nHpm6XaOmtEA:9\n a=QEXdDO2ut3YA:10","X-Proofpoint-ORIG-GUID":"ye574-iU3Iev19Ib485Mt-TFCoNQW-5B","X-Proofpoint-Virus-Version":"vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-04-23_03,2026-04-21_02,2025-10-01_01","X-Proofpoint-Spam-Details":"rule=outbound_notspam policy=outbound score=0\n adultscore=0 suspectscore=0 priorityscore=1501 malwarescore=0\n lowpriorityscore=0 clxscore=1015 bulkscore=0 impostorscore=0 spamscore=0\n phishscore=0 classifier=typeunknown authscore=0 authtc= authcc=\n route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000\n definitions=main-2604230148"}},{"id":3681545,"web_url":"http://patchwork.ozlabs.org/comment/3681545/","msgid":"<46ba7198-c5fd-44ca-9b35-b9970f400fdd@meta.com>","list_archive_url":null,"date":"2026-04-23T15:48:56","subject":"Re: [PATCH] PCI/P2PDMA: Avoid returning a provider for\n non_mappable_bars","submitter":{"id":93208,"url":"http://patchwork.ozlabs.org/api/people/93208/","name":"Matt Evans","email":"mattev@meta.com"},"content":"Hi Leon,\n\nOn 22/04/2026 16:19, Leon Romanovsky wrote:\n> \n> On Wed, Apr 22, 2026 at 03:22:53PM +0100, Matt Evans wrote:\n>> Hi Leon,\n>>\n>> On 21/04/2026 20:49, Leon Romanovsky wrote:\n>>>\n>>> On Tue, Apr 21, 2026 at 10:43:51AM -0700, Matt Evans wrote:\n>>>> Extend pcim_p2pdma_provider()'s checks to exclude functions that have\n>>>> pdev->non_mappable_bars set.\n>>>>\n>>>> Consumers such as VFIO were previously able to map these for access by\n>>>> the CPU or P2P. Update the comment on non_mappable_bars to show it\n>>>> refers to any access, not just userspace CPU access.\n>>>>\n>>>> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n>>>\n>>> I don't object to the patch, but this Fixes line doesn't look correct.\n>>> non_mappable_bars applies only to s390, which doesn't support p2p. That\n>>> wasn't prevented before 372d6d1b8ae3c refactoring too.\n>>\n>> Thanks; I'd chosen that commit as it adds the function that the additional\n>> test is being added to.\n> \n> Can I suggest slightly different solution?\n> If CONFIG_..._S390 is set, we will unset CONFIG_PCI_P2PDMA and pcim_p2pdma_provider()\n> will be compiled to return NULL, without changing non_mappable_bars\n> description.\n\nWhere we got to in\n\n https://lore.kernel.org/kvm/20260415181623.1021090-1-mattev@meta.com/\n\nwas that non_mappable_bars could be used in future for non-s390 quirks, \ni.e. s390 is the current (but potentially not only) user. Secondly, it \nisn't a P2P-specific issue because in\n\n https://lore.kernel.org/kvm/20260416131815.2729131-1-mattev@meta.com/\n\nI'm aiming to add mmap() support to VFIO DMABUFs, which (without a fix \nlike this) would allow CPU access too.\n\n\nThanks,\n\n\nMatt","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=meta.com header.i=@meta.com header.a=rsa-sha256\n header.s=s2048-2025-q2 header.b=NxYyTXuo;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-53051-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com\n header.b=\"NxYyTXuo\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=67.231.153.30","smtp.subspace.kernel.org;\n dmarc=pass (p=reject dis=none) header.from=meta.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=meta.com"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g1gXV4gSnz1y2d\n\tfor ; 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Update the comment on non_mappable_bars to show it\n>> refers to any access, not just userspace CPU access.\n>>\n>> Fixes: 372d6d1b8ae3c (\"PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation\")\n>> Signed-off-by: Matt Evans \n>> ---\n>>\n>> This arises from Alex Williamson's suggestion to test\n>> non_mappable_bars when getting the provider, with discussion here:\n>>\n>> https://lore.kernel.org/kvm/20260415181623.1021090-1-mattev@meta.com/\n>>\n>> The goal was to prevent a hole where VFIO could export DMABUFs for\n>> BARs marked non-mappable, and to fix for all users of the provider\n>> rather than just VFIO. Alex observed that non_mappable_bars should be\n>> taken to mean BARs weren't usable by the CPU _or_ peers and,\n>> considering that, its comment about userspace access wasn't quite\n>> right.\n>>\n>>\n>> drivers/pci/p2pdma.c | 3 ++-\n>> include/linux/pci.h | 2 +-\n>> 2 files changed, 3 insertions(+), 2 deletions(-)\n>>\n>> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c\n>> index 7c898542af8d..4a783413f466 100644\n>> --- a/drivers/pci/p2pdma.c\n>> +++ b/drivers/pci/p2pdma.c\n>> @@ -318,7 +318,8 @@ struct p2pdma_provider *pcim_p2pdma_provider(struct pci_dev *pdev, int bar)\n>> {\n>> \tstruct pci_p2pdma *p2p;\n>> \n>> -\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))\n>> +\tif (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM) ||\n>> +\t pdev->non_mappable_bars)\n>> \t\treturn NULL;\n>> \n>> \tp2p = rcu_dereference_protected(pdev->p2pdma, 1);\n>> diff --git a/include/linux/pci.h b/include/linux/pci.h\n>> index 2c4454583c11..1e6802017d6b 100644\n>> --- a/include/linux/pci.h\n>> +++ b/include/linux/pci.h\n>> @@ -508,7 +508,7 @@ struct pci_dev {\n>> \tunsigned int\tno_command_memory:1;\t/* No PCI_COMMAND_MEMORY */\n>> \tunsigned int\trom_bar_overlap:1;\t/* ROM BAR disable broken */\n>> \tunsigned int\trom_attr_enabled:1;\t/* Display of ROM attribute enabled? */\n>> -\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped to user-space */\n>> +\tunsigned int\tnon_mappable_bars:1;\t/* BARs can't be mapped by CPU or peers */\n>> \tpci_dev_flags_t dev_flags;\n>> \tatomic_t\tenable_cnt;\t/* pci_enable_device has been called */\n>> \n> \n> Should pcim_p2pdma_init() separately test pdev->non_mappable_bars\n> before the rcu-deref/kzalloc of the pci_p2pdma object and return\n> -EOPNOTSUPP?\n> \n> That then invokes the same error paths we'd see if we simply don't have\n> p2pdma in the kernel and handles the pci_p2pdma_add_resource() path\n> automatically as well.\n> \n> This pcim_p2pdma_provider() test is really then just suppressing the\n> WARN_ON that we'd otherwise see by not finding the p2p object on the\n> device. Thanks,\n\nThat makes sense, yes, it'll avoid the WARN that'd otherwise occur in \npci_p2pdma_add_resource().\n\nI'll do a v2 adding this check to pcim_p2pdma_init() as well. Hopefully \nLogan & Niklas's R-B will still apply.\n\n\nThanks,\n\n\nMatt","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=meta.com header.i=@meta.com header.a=rsa-sha256\n header.s=s2048-2025-q2 header.b=ibVHogOP;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-pci+bounces-53055-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com\n header.b=\"ibVHogOP\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=67.231.153.30","smtp.subspace.kernel.org;\n dmarc=pass (p=reject dis=none) header.from=meta.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=meta.com"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g1j3H6rrnz1yCv\n\tfor ; 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