From 98b04dd0b4577894520493d96bc4623387767445 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 26 Oct 2022 02:11:21 -0400 Subject: [PATCH] PCI: Fix pci_device_is_present() for VFs by checking PF pci_device_is_present() previously didn't work for VFs because it reads the Vendor and Device ID, which are 0xffff for VFs, which looks like they aren't present. Check the PF instead. Wei Gong reported that if virtio I/O is in progress when the driver is unbound or "0" is written to /sys/.../sriov_numvfs, the virtio I/O operation hangs, which may result in output like this: task:bash state:D stack: 0 pid: 1773 ppid: 1241 flags:0x00004002 Call Trace: schedule+0x4f/0xc0 blk_mq_freeze_queue_wait+0x69/0xa0 blk_mq_freeze_queue+0x1b/0x20 blk_cleanup_queue+0x3d/0xd0 virtblk_remove+0x3c/0xb0 [virtio_blk] virtio_dev_remove+0x4b/0x80 ... device_unregister+0x1b/0x60 unregister_virtio_device+0x18/0x30 virtio_pci_remove+0x41/0x80 pci_device_remove+0x3e/0xb0 This happened because pci_device_is_present(VF) returned "false" in virtio_pci_remove(), so it called virtio_break_device(). The broken vq meant that vring_interrupt() skipped the vq.callback() that would have completed the virtio I/O operation via virtblk_done(). [bhelgaas: commit log, simplify to always use pci_physfn(), add stable tag] Link: https://lore.kernel.org/r/20221026060912.173250-1-mst@redhat.com Reported-by: Wei Gong Tested-by: Wei Gong Signed-off-by: Michael S. Tsirkin Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org --- drivers/pci/pci.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 9f3cc82..fba9548 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6447,6 +6447,8 @@ bool pci_device_is_present(struct pci_dev *pdev) { u32 v; + /* Check PF if pdev is a VF, since VF Vendor/Device IDs are 0xffff */ + pdev = pci_physfn(pdev); if (pci_dev_is_disconnected(pdev)) return false; return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0); -- 2.7.4