From 9f47803503247c9ec414072c0724073a1c8c3433 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 26 Jul 2017 14:33:15 -0600 Subject: vfio/pci: Use pci_try_reset_function() on initial open Device lock bites again; if a device .remove() callback races a user calling ioctl(VFIO_GROUP_GET_DEVICE_FD), the unbind request will hold the device lock, but the user ioctl may have already taken a vfio_device reference. In the case of a PCI device, the initial open will attempt to reset the device, which again attempts to get the device lock, resulting in deadlock. Use the trylock PCI reset interface and return error on the open path if reset fails due to lock contention. Link: https://lkml.org/lkml/2017/7/25/381 Reported-by: Wen Congyang Signed-off-by: Alex Williamson --- drivers/vfio/pci/vfio_pci.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 063c1ce6fa42..f041b1a6cf66 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -226,7 +226,14 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) if (ret) return ret; - vdev->reset_works = (pci_reset_function(pdev) == 0); + /* If reset fails because of the device lock, fail this path entirely */ + ret = pci_try_reset_function(pdev); + if (ret == -EAGAIN) { + pci_disable_device(pdev); + return ret; + } + + vdev->reset_works = !ret; pci_save_state(pdev); vdev->pci_saved_state = pci_store_saved_state(pdev); if (!vdev->pci_saved_state) -- cgit v1.2.3 From 796b755066dd6254bfb6388fec901631e868d1c7 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 27 Jul 2017 10:39:33 -0600 Subject: vfio/pci: Fix handling of RC integrated endpoint PCIe capability size Root complex integrated endpoints do not have a link and therefore may use a smaller PCIe capability in config space than we expect when building our config map. Add a case for these to avoid reporting an erroneous overlap. Signed-off-by: Alex Williamson --- drivers/vfio/pci/vfio_pci_config.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c index 330a57024cbc..5628fe114347 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -839,7 +839,7 @@ static int vfio_exp_config_write(struct vfio_pci_device *vdev, int pos, /* Permissions for PCI Express capability */ static int __init init_pci_cap_exp_perm(struct perm_bits *perm) { - /* Alloc larger of two possible sizes */ + /* Alloc largest of possible sizes */ if (alloc_perm_bits(perm, PCI_CAP_EXP_ENDPOINT_SIZEOF_V2)) return -ENOMEM; @@ -1243,11 +1243,16 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos) vdev->extended_caps = (dword != 0); } - /* length based on version */ - if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) + /* length based on version and type */ + if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) { + if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END) + return 0xc; /* "All Devices" only, no link */ return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1; - else + } else { + if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END) + return 0x2c; /* No link */ return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2; + } case PCI_CAP_ID_HT: ret = pci_read_config_byte(pdev, pos + 3, &byte); if (ret) -- cgit v1.2.3