diff options
| author | Nishanth Aravamudan <naravamudan@nvidia.com> | 2025-02-07 14:56:00 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-10 14:41:37 +0200 |
| commit | 2738c01279606c751e7d11fa85f2d627c17d75aa (patch) | |
| tree | d9617e6e0b4a6420dbbfdfecf46fe8af761fce81 | |
| parent | c8983d4c06cc5322ded1cf16e89d662bbb022009 (diff) | |
PCI: Avoid reset when disabled via sysfs
[ Upstream commit 479380efe1625e251008d24b2810283db60d6fcd ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 db437572be47..e04f3290990b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5534,6 +5534,8 @@ 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; @@ -5610,6 +5612,8 @@ 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; |