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Thu, 20 Apr 2023 02:41:22 +0000 From: Dexuan Cui To: bhelgaas@google.com, davem@davemloft.net, decui@microsoft.com, edumazet@google.com, haiyangz@microsoft.com, jakeo@microsoft.com, kuba@kernel.org, kw@linux.com, kys@microsoft.com, leon@kernel.org, linux-pci@vger.kernel.org, lpieralisi@kernel.org, mikelley@microsoft.com, pabeni@redhat.com, robh@kernel.org, saeedm@nvidia.com, wei.liu@kernel.org, longli@microsoft.com, boqun.feng@gmail.com, ssengar@microsoft.com, helgaas@kernel.org Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, josete@microsoft.com, stable@vger.kernel.org Subject: [PATCH v3 5/6] PCI: hv: Add a per-bus mutex state_lock Date: Wed, 19 Apr 2023 19:40:36 -0700 Message-Id: <20230420024037.5921-6-decui@microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230420024037.5921-1-decui@microsoft.com> References: <20230420024037.5921-1-decui@microsoft.com> X-ClientProxiedBy: MW4P221CA0023.NAMP221.PROD.OUTLOOK.COM (2603:10b6:303:8b::28) To BL0PR2101MB1092.namprd21.prod.outlook.com (2603:10b6:207:30::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL0PR2101MB1092:EE_|SJ1PR21MB3411:EE_ X-MS-Office365-Filtering-Correlation-Id: 7f688bc2-30d8-4e33-8055-08db4148ba71 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 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 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7f688bc2-30d8-4e33-8055-08db4148ba71 X-MS-Exchange-CrossTenant-AuthSource: BL0PR2101MB1092.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Apr 2023 02:41:22.6300 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 2MKZy7yplie3QwkYdBy3LSJ1ALN5r0U6A0MYGeR/wH3bg6PZNEKO1z8yCW76TMrz4/hFai+fwmolc80iUax2nQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ1PR21MB3411 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In the case of fast device addition/removal, it's possible that hv_eject_device_work() can start to run before create_root_hv_pci_bus() starts to run; as a result, the pci_get_domain_bus_and_slot() in hv_eject_device_work() can return a 'pdev' of NULL, and hv_eject_device_work() can remove the 'hpdev', and immediately send a message PCI_EJECTION_COMPLETE to the host, and the host immediately unassigns the PCI device from the guest; meanwhile, create_root_hv_pci_bus() and the PCI device driver can be probing the dead PCI device and reporting timeout errors. Fix the issue by adding a per-bus mutex 'state_lock' and grabbing the mutex before powering on the PCI bus in hv_pci_enter_d0(): when hv_eject_device_work() starts to run, it's able to find the 'pdev' and call pci_stop_and_remove_bus_device(pdev): if the PCI device driver has loaded, the PCI device driver's probe() function is already called in create_root_hv_pci_bus() -> pci_bus_add_devices(), and now hv_eject_device_work() -> pci_stop_and_remove_bus_device() is able to call the PCI device driver's remove() function and remove the device reliably; if the PCI device driver hasn't loaded yet, the function call hv_eject_device_work() -> pci_stop_and_remove_bus_device() is able to remove the PCI device reliably and the PCI device driver's probe() function won't be called; if the PCI device driver's probe() is already running (e.g., systemd-udev is loading the PCI device driver), it must be holding the per-device lock, and after the probe() finishes and releases the lock, hv_eject_device_work() -> pci_stop_and_remove_bus_device() is able to proceed to remove the device reliably. Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Cc: stable@vger.kernel.org Acked-by: Lorenzo Pieralisi --- v2: Removed the "debug code". Fixed the "goto out" in hv_pci_resume() [Michael Kelley] Added Cc:stable v3: Added Michael's Reviewed-by. drivers/pci/controller/pci-hyperv.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 48feab095a144..3ae2f99dea8c2 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -489,7 +489,10 @@ struct hv_pcibus_device { struct fwnode_handle *fwnode; /* Protocol version negotiated with the host */ enum pci_protocol_version_t protocol_version; + + struct mutex state_lock; enum hv_pcibus_state state; + struct hv_device *hdev; resource_size_t low_mmio_space; resource_size_t high_mmio_space; @@ -2512,6 +2515,8 @@ static void pci_devices_present_work(struct work_struct *work) if (!dr) return; + mutex_lock(&hbus->state_lock); + /* First, mark all existing children as reported missing. */ spin_lock_irqsave(&hbus->device_list_lock, flags); list_for_each_entry(hpdev, &hbus->children, list_entry) { @@ -2593,6 +2598,8 @@ static void pci_devices_present_work(struct work_struct *work) break; } + mutex_unlock(&hbus->state_lock); + kfree(dr); } @@ -2741,6 +2748,8 @@ static void hv_eject_device_work(struct work_struct *work) hpdev = container_of(work, struct hv_pci_dev, wrk); hbus = hpdev->hbus; + mutex_lock(&hbus->state_lock); + /* * Ejection can come before or after the PCI bus has been set up, so * attempt to find it and tear down the bus state, if it exists. This @@ -2777,6 +2786,8 @@ static void hv_eject_device_work(struct work_struct *work) put_pcichild(hpdev); put_pcichild(hpdev); /* hpdev has been freed. Do not use it any more. */ + + mutex_unlock(&hbus->state_lock); } /** @@ -3562,6 +3573,7 @@ static int hv_pci_probe(struct hv_device *hdev, return -ENOMEM; hbus->bridge = bridge; + mutex_init(&hbus->state_lock); hbus->state = hv_pcibus_init; hbus->wslot_res_allocated = -1; @@ -3670,9 +3682,11 @@ static int hv_pci_probe(struct hv_device *hdev, if (ret) goto free_irq_domain; + mutex_lock(&hbus->state_lock); + ret = hv_pci_enter_d0(hdev); if (ret) - goto free_irq_domain; + goto release_state_lock; ret = hv_pci_allocate_bridge_windows(hbus); if (ret) @@ -3690,12 +3704,15 @@ static int hv_pci_probe(struct hv_device *hdev, if (ret) goto free_windows; + mutex_unlock(&hbus->state_lock); return 0; free_windows: hv_pci_free_bridge_windows(hbus); exit_d0: (void) hv_pci_bus_exit(hdev, true); +release_state_lock: + mutex_unlock(&hbus->state_lock); free_irq_domain: irq_domain_remove(hbus->irq_domain); free_fwnode: @@ -3945,20 +3962,26 @@ static int hv_pci_resume(struct hv_device *hdev) if (ret) goto out; + mutex_lock(&hbus->state_lock); + ret = hv_pci_enter_d0(hdev); if (ret) - goto out; + goto release_state_lock; ret = hv_send_resources_allocated(hdev); if (ret) - goto out; + goto release_state_lock; prepopulate_bars(hbus); hv_pci_restore_msi_state(hbus); hbus->state = hv_pcibus_installed; + mutex_unlock(&hbus->state_lock); return 0; + +release_state_lock: + mutex_unlock(&hbus->state_lock); out: vmbus_close(hdev->channel); return ret;