diff options
| author | Nishanth Aravamudan <naravamudan@nvidia.com> | 2025-02-07 14:56:00 -0600 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2025-03-04 17:23:21 -0600 |
| commit | 479380efe1625e251008d24b2810283db60d6fcd (patch) | |
| tree | 5e73c9e0c1530db5ef9ce7922157e3808fc90f5f /drivers/pci/pci.c | |
| parent | 800ce277f419a9b142a9ca0ec5a054225c5ff05b (diff) | |
PCI: Avoid reset when disabled via sysfs
After d88f521da3ef ("PCI: Allow userspace to query and set device reset
mechanism"), userspace can disable reset of specific PCI devices by writing
an empty string to the sysfs reset_method file.
However, pci_slot_resettable() does not check pci_reset_supported(), which
means that pci_reset_function() will still reset the device even if
userspace has disabled all the reset methods.
I was able to reproduce this issue with a vfio device passed to a qemu
guest, where I had disabled PCI reset via sysfs.
Add an explicit check of pci_reset_supported() in both
pci_slot_resettable() and pci_bus_resettable() to ensure both the reset
status and reset execution are bypassed if an administrator disables it for
a device.
Link: https://lore.kernel.org/r/20250207205600.1846178-1-naravamudan@nvidia.com
Fixes: d88f521da3ef ("PCI: Allow userspace to query and set device reset mechanism")
Signed-off-by: Nishanth Aravamudan <naravamudan@nvidia.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: Amey Narkhede <ameynarkhede03@gmail.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Yishai Hadas <yishaih@nvidia.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 3d13bb8e5c53..c6c25b910bde 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5410,6 +5410,8 @@ static bool pci_bus_resettable(struct pci_bus *bus) return false; list_for_each_entry(dev, &bus->devices, bus_list) { + if (!pci_reset_supported(dev)) + return false; if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resettable(dev->subordinate))) return false; @@ -5486,6 +5488,8 @@ static bool pci_slot_resettable(struct pci_slot *slot) list_for_each_entry(dev, &slot->bus->devices, bus_list) { if (!dev->slot || dev->slot != slot) continue; + if (!pci_reset_supported(dev)) + return false; if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resettable(dev->subordinate))) return false; |