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The device cdev path doesn't have a secure way for it", >>> since it's still doable to achieve the same "secure" level in cdev path and the >>> group path is not that "secure" :) >> >> It is more that the group path had an API that allowed for multiple >> FDs without an actual need to ever use that. You can always make more >> FDs with dup. >> >> There is no reason for this functionality, we just have to keep it >> working as a matter of uABI compatability and we are being more strict >> in the new APIs. > Thanks for clarification. > Regarding to uABI compatability, even after being more strict and returning > error when opening the second FD in group path, the uABI compatability is still > maintained? e.g. > QEMU would correctly reports "Verify all devices in group xxx are bound to > vfio- or pci-stub and not already in use" in that case. > Given there's no actual users, could we also remove the support of multiple FDs > in group path to simplify code? QEMU is not the only user of vfio. DPDK or other applications may have usage for multi-fds. -- Regards, Yi Liu