Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/1.1/patches/2221593/?format=api
{ "id": 2221593, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2221593/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260409215232.399350-1-decui@microsoft.com/", "project": { "id": 28, "url": "http://patchwork.ozlabs.org/api/1.1/projects/28/?format=api", "name": "Linux PCI development", "link_name": "linux-pci", "list_id": "linux-pci.vger.kernel.org", "list_email": "linux-pci@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null }, "msgid": "<20260409215232.399350-1-decui@microsoft.com>", "date": "2026-04-09T21:52:32", "name": "Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "474eda5b6735a5166280d3f3bf08581f61e3ddea", "submitter": { "id": 64601, "url": "http://patchwork.ozlabs.org/api/1.1/people/64601/?format=api", "name": "Dexuan Cui", "email": "decui@microsoft.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-pci/patch/20260409215232.399350-1-decui@microsoft.com/mbox/", "series": [ { "id": 499363, "url": "http://patchwork.ozlabs.org/api/1.1/series/499363/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/list/?series=499363", "date": "2026-04-09T21:52:32", "name": "Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/499363/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2221593/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2221593/checks/", "tags": {}, "headers": { "Return-Path": "\n <linux-pci+bounces-52234-incoming=patchwork.ozlabs.org@vger.kernel.org>", "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 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-52234-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)", "smtp.subspace.kernel.org;\n arc=none smtp.client-ip=13.77.154.182", "smtp.subspace.kernel.org;\n dmarc=pass (p=reject dis=none) header.from=microsoft.com", "smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=linux.microsoft.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 4fsDFk3Bszz1yCv\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 10 Apr 2026 07:53:14 +1000 (AEST)", "from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id 0ABFA302A1B9\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 9 Apr 2026 21:52:57 +0000 (UTC)", "from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 7591A35B653;\n\tThu, 9 Apr 2026 21:52:51 +0000 (UTC)", "from linux.microsoft.com (linux.microsoft.com [13.77.154.182])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 299CD37C0FE;\n\tThu, 9 Apr 2026 21:52:50 +0000 (UTC)", "by linux.microsoft.com (Postfix, from userid 1009)\n\tid EA39620B7129; Thu, 9 Apr 2026 14:52:49 -0700 (PDT)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775771571; cv=none;\n b=F5X9wga9rlBQCGFT2b+0NK89dKFaKMfnEyhYTA2A/l3OQk5pYJL7CM0HebYQuGJo38xQR5EcLLABMSPstnVfR0+rjD8Ah1c/Njjl9A2C6Z3Q2FJlLyUOWmeuhfLv/nIJNfrP5Ik6QDstpWOdPvtOBx19MZ0ncPcQ6vyT/Vp0CEI=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775771571; c=relaxed/simple;\n\tbh=tFfRzLm4MwVx6uT8622X3ap+XCSlK+8946afWlhqItQ=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=pT2AnsvUy5S3mACPF/Gun3qwheDcKdbMLJUtRTYrc7oz7brwB/yZ3o8gUCgDDr0zOeAKdHYwALNmb5KZK5/CRj1ygYG2nEd3hhFq6uXG2D9bm5kCe2duP5oYzjFckEWiX9si62L1buMOsqtoT8bxiD/Mz/rhoQgI4iMu8Sw7RDk=", "ARC-Authentication-Results": "i=1; smtp.subspace.kernel.org;\n dmarc=pass (p=reject dis=none) header.from=microsoft.com;\n spf=pass smtp.mailfrom=linux.microsoft.com;\n arc=none smtp.client-ip=13.77.154.182", "DKIM-Filter": "OpenDKIM Filter v2.11.0 linux.microsoft.com EA39620B7129", "From": "Dexuan Cui <decui@microsoft.com>", "To": "kys@microsoft.com,\n\thaiyangz@microsoft.com,\n\twei.liu@kernel.org,\n\tdecui@microsoft.com,\n\tlongli@microsoft.com,\n\tlpieralisi@kernel.org,\n\tkwilczynski@kernel.org,\n\tmani@kernel.org,\n\trobh@kernel.org,\n\tbhelgaas@google.com,\n\tlinux-hyperv@vger.kernel.org,\n\tlinux-pci@vger.kernel.org", "Cc": "linux-kernel@vger.kernel.org,\n\tMukesh Rathor <mrathor@linux.microsoft.com>", "Subject": "[PATCH] Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in\n pci-hyperv", "Date": "Thu, 9 Apr 2026 14:52:32 -0700", "Message-ID": "<20260409215232.399350-1-decui@microsoft.com>", "X-Mailer": "git-send-email 2.43.7", "Precedence": "bulk", "X-Mailing-List": "linux-pci@vger.kernel.org", "List-Id": "<linux-pci.vger.kernel.org>", "List-Subscribe": "<mailto:linux-pci+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:linux-pci+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit" }, "content": "With commit f84b21da3624 (\"PCI: hv: Don't load the driver for baremetal root partition\"),\nthe bare metal Linux root partition won't use the pci-hyperv driver, but\nwhen a Linux VM runs on the Linux root partition, pci-hyperv's module_init\nfunction init_hv_pci_drv() can still run, e.g. in the case of\nCONFIG_PCI_HYPERV=y, even if the VMBus driver is not used in such a VM\n(i.e. the hv_vmbus driver's init function returns -ENODEV due to\nvmbus_root_device being NULL).\n\nIn such a Linux VM, init_hv_pci_drv() runs with a side effect: the 3\nhvpci_block_ops callbacks are set to functions that depend on hv_vmbus.\n\nLater, when the MLX driver in such a VM invokes the callbacks, e.g. in\ndrivers/net/ethernet/mellanox/mlx5/core/lib/hv.c:\nmlx5_hv_register_invalidate(), hvpci_block_ops.reg_blk_invalidate() is\nhv_register_block_invalidate() rather than a NULL function pointer, and\nhv_register_block_invalidate() assumes that it can find a struct\nhv_pcibus_device from pdev->bus->sysdata, which is false in such a VM.\n\nConsequently, hv_register_block_invalidate() -> get_pcichild_wslot() ->\nspin_lock_irqsave() may hang since it can be accessing an invalid\nspinlock pointer.\n\nFix the issue by exporting hv_vmbus_exists() and using it in pci-hyperv:\n\n hv_root_partition() is true and hv_nested is false ==>\n\thv_vmbus_exists() is false.\n\n hv_root_partition() is true and hv_nested is true ==>\n\thv_vmbus_exists() is true.\n\n hv_root_partition() is false ==> hv_vmbus_exists() is true.\n\nWhile at it, rename vmbus_exists() to hv_vmbus_exists() to follow the\nconvention that all public functions have the hv_ prefix; also change\nthe return value's type from int to bool to make the code more readable;\nalso move the two pr_info() calls.\n\nReported-by: Mukesh Rathor <mrathor@linux.microsoft.com>\nSigned-off-by: Dexuan Cui <decui@microsoft.com>\n---\n drivers/hv/vmbus_drv.c | 20 ++++++++------------\n drivers/pci/controller/pci-hyperv.c | 2 +-\n include/linux/hyperv.h | 2 ++\n 3 files changed, 11 insertions(+), 13 deletions(-)", "diff": "diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c\nindex bc4fc1951ae1..2c8936efc8d1 100644\n--- a/drivers/hv/vmbus_drv.c\n+++ b/drivers/hv/vmbus_drv.c\n@@ -101,13 +101,11 @@ struct device *hv_get_vmbus_root_device(void)\n }\n EXPORT_SYMBOL_GPL(hv_get_vmbus_root_device);\n \n-static int vmbus_exists(void)\n+bool hv_vmbus_exists(void)\n {\n-\tif (vmbus_root_device == NULL)\n-\t\treturn -ENODEV;\n-\n-\treturn 0;\n+\treturn vmbus_root_device != NULL;\n }\n+EXPORT_SYMBOL_GPL(hv_vmbus_exists);\n \n static u8 channel_monitor_group(const struct vmbus_channel *channel)\n {\n@@ -1582,11 +1580,10 @@ int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, c\n {\n \tint ret;\n \n-\tpr_info(\"registering driver %s\\n\", hv_driver->name);\n+\tif (!hv_vmbus_exists())\n+\t\treturn -ENODEV;\n \n-\tret = vmbus_exists();\n-\tif (ret < 0)\n-\t\treturn ret;\n+\tpr_info(\"registering driver %s\\n\", hv_driver->name);\n \n \thv_driver->driver.name = hv_driver->name;\n \thv_driver->driver.owner = owner;\n@@ -1612,9 +1609,8 @@ EXPORT_SYMBOL_GPL(__vmbus_driver_register);\n */\n void vmbus_driver_unregister(struct hv_driver *hv_driver)\n {\n-\tpr_info(\"unregistering driver %s\\n\", hv_driver->name);\n-\n-\tif (!vmbus_exists()) {\n+\tif (hv_vmbus_exists()) {\n+\t\tpr_info(\"unregistering driver %s\\n\", hv_driver->name);\n \t\tdriver_unregister(&hv_driver->driver);\n \t\tvmbus_free_dynids(hv_driver);\n \t}\ndiff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c\nindex 2c7a406b4ba8..226b8bb802f3 100644\n--- a/drivers/pci/controller/pci-hyperv.c\n+++ b/drivers/pci/controller/pci-hyperv.c\n@@ -4166,7 +4166,7 @@ static int __init init_hv_pci_drv(void)\n \tif (!hv_is_hyperv_initialized())\n \t\treturn -ENODEV;\n \n-\tif (hv_root_partition() && !hv_nested)\n+\tif (!hv_vmbus_exists())\n \t\treturn -ENODEV;\n \n \tret = hv_pci_irqchip_init();\ndiff --git a/include/linux/hyperv.h b/include/linux/hyperv.h\nindex dfc516c1c719..5459e776ec17 100644\n--- a/include/linux/hyperv.h\n+++ b/include/linux/hyperv.h\n@@ -1304,6 +1304,8 @@ static inline void *hv_get_drvdata(struct hv_device *dev)\n \n struct device *hv_get_vmbus_root_device(void);\n \n+bool hv_vmbus_exists(void);\n+\n struct hv_ring_buffer_debug_info {\n \tu32 current_interrupt_mask;\n \tu32 current_read_index;\n", "prefixes": [] }