vfio-pci and pci-stub use new_id to bind devices. But one can add same IDs multiple times, for example: # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id -bash: echo: write error: No such device This doesn't cause user-visible broken behavior, but not user friendly. he has to remove same IDs same times to ensure it's completely gone. Changed to only allow one dynamic entry of the same kind, after fix: # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id -bash: echo: write error: File exists # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id -bash: echo: write error: No such device v3: add a separate patch to process dependency issue per Bjorn make commit log more clear per Bjorn v2: revert the export of pci_match_device() per Christoph combind PATCH1 and PATCH2 into one. v2 link:https://lkml.org/lkml/2020/10/25/347 Zhenzhong Duan (2): PCI: move pci_match_device() ahead of new_id_store() PCI: avoid duplicate IDs in dynamic IDs list drivers/pci/pci-driver.c | 146 +++++++++++++++++++++++------------------------ 1 file changed, 73 insertions(+), 73 deletions(-) -- 1.8.3.1 Zhenzhong Duan (2): PCI: move pci_match_device() ahead of new_id_store() PCI: avoid duplicate IDs in dynamic IDs list drivers/pci/pci-driver.c | 146 +++++++++++++++++++++++------------------------ 1 file changed, 73 insertions(+), 73 deletions(-) -- 1.8.3.1