On Wed, Jun 12, 2024 at 03:45:48PM GMT, Frederic Griffoul [off-list ref] wrote:

To be honest my initial idea was to store an affinity mask per vfio group, which
can be done in the privileged process setting the vfio group/device owner, and
later apply the mask to each interrupt of each device in the group.

It would still require to fix the affinity of all the interrupts if
the vfio group affinity is
changed (or deliberately ignore this case). And it did not match
exactly my use case
where I need the process handling the interrupts to sometimes be able
to change them
but always within the cpuset. So I would still need the current patch,
in addition to
a new ioctl() to set the affinity mask of a vfio group.

It's not clear to me what is the relation between the process A calling
that ioctl() (and whose cpuset is used to check affinity for)
and a process B that ends up handling the IRQ.
At which place would process B be scheduled on IRQ's affinity CPUs?
(I'm not familiar with VFIO.)

Thanks,
Michal