> On Dec 13, 2022, at 8:39 AM, Cédric Le Goater <[email protected]> wrote:
>
> On 11/9/22 00:13, John Johnson wrote:
>>
>> +
>> + /* must send all valid FDs or all invalid FDs in single msg */
>
> why is that ?
>
This has to do with how VFIO sends FDs to the kernel. The
ioctl() i/f has an array of FDs, with -1 signifying an invalid one.
FDs can only be sent over a UNIX socket as a single array of them
(all must be valid, no -1 holes in the array).
In order to emulate the ioctl() use, we’d need to send an
ancillary array to map the ordinal index of irq_data to the ordinal
index of the FDs in the message. Since multi-FD sends are only done
at device set-up, it seemed simpler to just break them up.
JJ
