tmakatos
commented
2 weeks ago s/shadow io fd/shadow ioevent fd
Shadow ioeventfd is a mechanism to avoid the switch from KVM to QEMU when running nvmf/vfio-user in interrupt mode. This is achieved by KVM writing the doorbell value to shadow piece of memory and then kicking a separate ioeventfd that wakes up SPDK, so QEMU doesn't have to wake up at all.
- https://qemu.googlesource.com/libvfio-user/+/refs/heads/master/docs/ioregionfd.md
- https://lore.kernel.org/kvm/20221005211551.152216-1-thanos.makatos@nutanix.com/
[30min]